Heading 1 - Hampshire County Council

Heading 1 - Hampshire County Council
HCC Property Services.
Engineering Services Unit
Standard specification for materials,
workmanship and installation of electrical
services Parts B.
October 2011
Document:
Standard specification for materials, workmanship
and installation of electrical services installations
Parts B.
HCC Property Services Reference:
F7111/sp/rc Version 1.0 (B)
Author:
Name: Steve Perry
Position: Principal Electrical Engineer.
Date:
October 2011
Document Checked and Approved:
Name: Andy Howard
Position: Engineering Team Leader
Signed:
Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Contents
B1
Materials .........................................................................................................................................................................................7
B1.1
Steel and PVC conduit systems ..........................................................................................................................7
B1.1.1
General ..........................................................................................................................................7
B1.1.2.
Installation.....................................................................................................................................7
B1.2
Flexible conduit ...........................................................................................................................................................9
B1.3
Cable trunking .......................................................................................................................................................... 10
B1.3.1
General ....................................................................................................................................... 10
B1.3.2
Installation.................................................................................................................................. 10
B1.3.3.
Ceiling and overhead trunking .......................................................................................... 12
B1.3.4.
Lighting trunking ...................................................................................................................... 12
B1.3.5
Floor trunking ........................................................................................................................... 12
B1.4
Bench and skirting trunking ................................................................................................................................ 12
B1.5
Rising busbar trunking .......................................................................................................................................... 13
B1.6
Cable tray, cable-basket and cable ladder .................................................................................................. 13
B1.7
Colour coding and identification of conduits/trunking and conductors ............................................. 14
B1.7.1
General ....................................................................................................................................... 14
B1.7.2
Identification of conductors ................................................................................................. 15
B1.8
Service ducts, trenches & tunnels ................................................................................................................... 16
B1.8.1
General ....................................................................................................................................... 16
B1.9
Catenary wire support ........................................................................................................................................... 19
B1.10 Cables concealed within wall ............................................................................................................................. 19
B1.11 PVC covered single core cables ...................................................................................................................... 20
B1.12 PVC covered single core cable installation ................................................................................................. 20
B1.13 PVC insulated and sheathed cables ............................................................................................................... 20
B1.14 Installation of PVC insulated and sheathed cables .................................................................................. 21
B1.15 MICC cables ............................................................................................................................................................. 22
B1.15.1
General ....................................................................................................................................... 22
B1.15.2
Installation.................................................................................................................................. 22
B1.16 Fire resistant cables............................................................................................................................................... 23
B1.16.1
General ....................................................................................................................................... 23
B1.16.2
Installation.................................................................................................................................. 23
B1.17 Flexible cables ......................................................................................................................................................... 24
B1.18 XLPE and PVC armoured cables..................................................................................................................... 24
B1.18.1
General ....................................................................................................................................... 24
B1.18.2
Installation.................................................................................................................................. 24
B1.18.3
Terminations ............................................................................................................................. 26
B1.19 Fabricated switchboards ...................................................................................................................................... 27
B1.20 Cubicle switchboards and panel boards ....................................................................................................... 28
B1.21 Busbar chambers .................................................................................................................................................... 29
B1.22 Distribution boards ................................................................................................................................................. 29
B1.23 Moulded case circuit breakers .......................................................................................................................... 30
B1.24 Miniature circuit breakers .................................................................................................................................... 30
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Fuses ........................................................................................................................................................................... 31
Fuse switches ........................................................................................................................................................... 31
Contactors.................................................................................................................................................................. 32
Motor starters ........................................................................................................................................................... 32
Control panels .......................................................................................................................................................... 33
Lighting switches ..................................................................................................................................................... 33
Ceiling lighting switches ....................................................................................................................................... 34
Ampere socket outlets .......................................................................................................................................... 34
Fused connection units ........................................................................................................................................ 34
Cooker control unit ................................................................................................................................................. 35
Shaving outlets ........................................................................................................................................................ 35
Accessory boxes ..................................................................................................................................................... 36
Ceiling accessories ................................................................................................................................................ 36
Lamps .......................................................................................................................................................................... 37
Electromagnetic compatibility ............................................................................................................................ 37
END OF SECTION B1 ................................................................................................................................... 38
Installations ................................................................................................................................................................................ 39
B2.1
Lighting circuits ........................................................................................................................................................ 39
B2.2
Erection of luminaires ........................................................................................................................................... 39
B2.2.1
General ....................................................................................................................................... 39
B.2.2.2
Fixing of luminaires ................................................................................................................ 40
B.2.2.3
Final connections to luminaires ........................................................................................ 41
B2.3
Emergency lighting ................................................................................................................................................. 42
B2.3.1
General ....................................................................................................................................... 42
B.2.3.2.
Self-contained luminaires .................................................................................................... 42
B2.3.4
Central battery systems ....................................................................................................... 42
B2.4
External lighting ....................................................................................................................................................... 43
B2.5
General purpose ring circuits ............................................................................................................................. 43
B2.5.1
CDT workshops/technology and science rooms ....................................................... 44
B2.5.2
Science Classrooms ............................................................................................................. 45
B2.5.3
Food technology classrooms ............................................................................................. 46
B2.6
Kilns .............................................................................................................................................................................. 46
B2.7
Fixed equipment ...................................................................................................................................................... 47
B2.8
Mechanical plant services installation ............................................................................................................ 47
B2.9
Fan coil units ............................................................................................................................................................. 48
B2.10 Electric water heaters ........................................................................................................................................... 49
B2.11 Electric shower heaters ........................................................................................................................................ 49
B2.12 Cooker Circuits ........................................................................................................................................................ 50
B2.13 Electric hand driers ................................................................................................................................................ 50
B2.14 Electric heaters ........................................................................................................................................................ 50
B2.15 Air conditioning units ............................................................................................................................................. 51
B2.16 Ventilation fan installation ................................................................................................................................... 51
B.2.16.1
General ....................................................................................................................................... 51
B2.16.2
Window mounted .................................................................................................................... 51
B1.25
B1.26
B1.27
B1.28
B1.29
B1.30
B1.31
B1.32
B1.33
B1.34
B1.35
B1.36
B1.37
B1.38
B1.39
B2
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
B.2.16.3
Wall mounted ........................................................................................................................... 52
B.2.16.4
Toilet units ................................................................................................................................. 52
B2.16.5
Roof mounted........................................................................................................................... 52
B.2.16.6
Industrial type ........................................................................................................................... 52
B2.17 Call systems .............................................................................................................................................................. 52
B2.18 Door entry systems ................................................................................................................................................ 53
B2.19 Personal attack systems ...................................................................................................................................... 53
B2.20 Television aerial system ....................................................................................................................................... 53
B.2.20.1
General ....................................................................................................................................... 53
B.2.20.2
Television distribution conduits ......................................................................................... 54
B2.21 Telephone system .................................................................................................................................................. 54
B.2.21.1
General ....................................................................................................................................... 54
B.2.21.2
Telephone system conduits ............................................................................................... 54
B.2.21.3
Call routing apparatus .......................................................................................................... 54
B.2.21.4
Cables containing flammable materials ........................................................................ 55
B2.21.5
Maintenance ............................................................................................................................. 55
B.2.21.6.
Line standards ......................................................................................................................... 55
B2.22 IT services installation .......................................................................................................................................... 56
B2.22.1
General ....................................................................................................................................... 56
B.2.22.2
Cabling standards .................................................................................................................. 57
B2.22.3
Testing and certification ....................................................................................................... 57
B2.22.4 Interactive whiteboard ........................................................................................................................................... 57
B2.23 Fire alarm system ................................................................................................................................................... 57
B.2.23.1.
General ....................................................................................................................................... 57
B2.23.2
Residential Premises ............................................................................................................ 58
B2.23.4
Schools ....................................................................................................................................... 59
B.2.23.5
Offices, Museums, Libraries etc ....................................................................................... 63
B.2.23.6
Ancillary devices ..................................................................................................................... 63
B2.23.7
Central Monitoring Link ........................................................................................................ 63
B2.23.8
Installation.................................................................................................................................. 64
B2.23.9
Zoned alarms/staged evacuation..................................................................................... 64
B2.24 Lift services installation ........................................................................................................................................ 64
B2.24.1
General ....................................................................................................................................... 64
B2.24.2
Electrical supply ...................................................................................................................... 65
B2.24.3
Secondary supplies ............................................................................................................... 65
B2.24.4
Communication........................................................................................................................ 66
B2.24.5
Lift car sizes .............................................................................................................................. 66
B2.24.6
Lift call controls ........................................................................................................................ 66
B2.24.7
Floor call buttons .................................................................................................................... 67
Reference/Notes ............................................................................................................................................... 67
B2.24.8
Lift safety systems.................................................................................................................. 67
B2.24.9
Signage ....................................................................................................................................... 68
B2.24.10
Lift shaft ...................................................................................................................................... 68
B2.25 Refuge call systems............................................................................................................................................... 68
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
B2.26
B2.27
B2.28
B2.29
Lightning protection installation ........................................................................................................................ 69
Intruder alarm ........................................................................................................................................................... 69
CCTV ........................................................................................................................................................................... 70
Sustainable energy systems .............................................................................................................................. 70
B2.29.1.
General ....................................................................................................................................... 70
B2.29.2
Access to equipment ............................................................................................................. 70
B2.29.3
Isolation and earthing of a sustainable energy system .......................................... 70
B.2.29.4
Synchronisation with the buildings main electrical supply .................................... 71
B2.29.5
Induced voltages and electro-magnetic interference (EMI) .................................. 71
B.2.29.6
Metering of sustainable energy systems ...................................................................... 71
B.2.29.7
Documentation and certification ....................................................................................... 71
B.2.29.8
Annual maintenance ............................................................................................................. 72
END OF SECTION B2 ................................................................................................................................... 72
.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
B1 Materials
B1.1
Steel and PVC conduit systems
B1.1.1
General
Conduit systems enclosing single core cables shall form a continuous enclosure providing mechanical
protection, and be of sufficient size to accommodate the cable in accordance with the BS7671 and any
subsequent amendments.
The type of conduit to be used shall be as detailed in the Particular Specification Part C and will be either:i)
Heavy gauge steel, welded, screwed, conduit to BS 4568 Part 1, black enamel for internal use,
galvanised for external use or where exposed to moisture.
ii)
Heavy gauge, high impact UPVC conduit to BS 4607, 4678 and BS EN50086-2-1.
No conduit smaller than 20mm shall be used, and where conduits are installed for the use of other services they
shall be complete with a draw wire.
Manufactured „Bend‟, „Elbow‟ or „Tee‟ fittings shall not be used except with the express permission of the
Engineer.
Conduit boxes for steel systems shall be of malleable iron or pressed steel, enamel or galvanised finish
manufactured in accordance with BS EN50086-1.
Conduit boxes for PVC systems shall be manufactured in accordance with BS 4607 Part 1.
Conduit boxes that do not serve as outlets, shall be fitted with lids secured with brass round head screws. All
lighting points shall terminate in a 50mm BESA malleable, iron or heat resisting heavy gauge PVC conduit box.
Fittings and boxes shall be enamelled, galvanised or PVC to match the respective types of conduit.
B1.1.2.
Installation
Conduits shall be laid in straight or symmetrical lines. Careful consideration being taken, to ensure that the
most appropriate and logical routes are used in conjunction with other services.
Conduits shall not touch any other pipes and in all cases shall be at least 150mm from heating pipes, gas pipes
and other sources of radiant heat and shall be mounted below rather than above such pipes.
Inspection bends, elbows or tees shall not be used in any part of the installation. Where necessary, use shall
be made of circular conduit boxes.
Steel conduit bends or sets shall be made cold, using a bending machine without altering the section of the
conduit. The inner radius of any bend shall not be less than 2.5 times the outside diameter of the conduit.
All steel conduit is to be so threaded that ends of the tubes butt close together in couplings and sockets without
any excess thread showing. The ends shall be filed square and reamered with a purpose made reamer to
remove all burrs.
Where steel conduits enter distribution boards, accessory boxes, or any equipment without threaded entries,
connection shall be made by means of threaded couplers and smooth bore, brass hexagonal headed male
bushes, which shall be tightened with a spanner.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Saddles for steel conduits shall be spaced at not more than:
1800mm
1200mm
600mm
300mm
Vertically
Horizontally
From an accessory
From one side of a bend or set
Saddles shall be of the spacer bar type to match the finish of the conduit being fixed to the bar using round
headed non ferrous screws.
Steel conduits and accessories shall be protected from the weather both during storage and during erection.
Care shall be taken to ensure that conduits installed during the progress of the building works are protected
from damage by other trades, and to prevent conduit threads being damaged and building materials entering
conduits, boxes etc.
Care shall be taken to avoid damaging the protecting enamel or galvanising when screwing and bending.
Damaged enamel or galvanising and running threads shall be coated with a matching paint finish immediately
after erection.
Short lengths of steel conduit provided to sleeve sheathed cables through walls shall be fitted with brass female
ring bushes.
PVC conduit bends or sets shall be made according to the manufacturers recommendations.
Bending springs obtained from the manufacturer of the conduit appropriate to the size and grade of the conduit
shall be used for making all sets and bends in conduit without corrugation. Bends in conduit larger than 25mm
or in cold weather shall be made using both spring and bending machine. If heat treatment is used to assist
bending, under no circumstances shall the heat source be applied direct to the conduit.
Adequate allowance shall be made for longitudinal expansion and contraction of surface PVC conduit. Saddles
shall be of a size such that the conduit will slide freely within the saddle on expansion and expansion couplers
installed in straight runs of conduit at a maximum of 4 metre intervals.
Joints between conduit, coupler and PVC conduit accessories, shall be made with a PVC solvent adhesive,
providing a watertight seal as approved by the manufacturer. Where expansion couplers are installed, the
coupler shall be permanently bonded to one conduit end, and the other conduit end allowed to move freely
within the coupler, either by use of an adhesive that remains flexible or silicon grease.
Where conduits enter distribution boards, busbar chambers and accessories a manufactured adaptor shall be
used.
Saddles for PVC conduits shall be spaced at not more than:
1200mm
900mm
400mm
150mm
Vertically
Horizontally
From an accessory
Either side of a bend or a set in the conduit.
Where possible all conduits shall be concealed in the building fabric. Consideration shall be given to the
amount of chasing that may be required when planning routes, to try and keep this to a minimum.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Conduits installed in floor screeds or wall chases shall be firmly fixed in position with crampets or saddles.
Chases in walls shall be deep enough to ensure that the conduit is covered by the full thickness of the render
and plaster.
Conduits laid in the floor slab or in reinforced concrete walls, columns etc; shall be fastened to the reinforcement
or formwork by the Contractor, who shall be responsible for ensuring that conduit and boxes are not displaced
before and during the pouring operation. Unless otherwise specified conduits in these situations shall be
galvanised steel.
Conduits installed in wood joisted floor and ceilings shall be run parallel and at right angles to the joists,
securely fixed at not more than 1500mm spacing.
Where it is necessary to drill or slot joists the approval of the Contract Administrator shall be obtained before the
drilling or slotting is carried out.
Where PVC conduits are installed either surface across ceilings or above suspended ceilings, the conduits
shall be securely fixed by means of metal fixings every 1.5m in addition to the spacings and requirements of
BS7671, to prevent cables falling in the event of fire situation.
Generally, where conduits are to be installed from point to point in a straight run without bends, draw-in boxes
shall be provided in every 10m of conduit run, but where conduits are run from point to point with not more than
two right-angle bends, draw-in boxes shall be provided at intervals not more than 8m.
Draw in box positions shall be agreed with the Contract Administrator before installation, being located so that
they are readily accessible after building completion.
Conduits for lighting circuits shall be installed as a loop-in system using back entry BESA conduit boxes. The
conduit box shall be installed flush with the underside of the ceiling. Extension rings shall be used to extend
conduit boxes where necessary.
All boxes shall be securely fixed to the structure by at least two screws passing through the base of the box,
boxes installed externally, or in damp situations shall have heavy pattern lid with gasket.
Conduits, conduit boxes etc, installed during the progress of the building works shall be protected from damage
by other trades, and to prevent the ingress of wet or dry building materials. The Contractor will be held entirely
responsible for any additional costs resulting from the blockage of boxes or conduits.
All surface installed conduits shall be installed to suit as far as practicable the architectural features. Conduits
shall be installed in vertical and horizontal directions except where it is desirable to follow the line of a
constructional feature.
No wiring shall be drawn into the conduit system until after it has been fully erected. Steel conduit shall be
electrically continuous through out its length, and each section of conduit shall be tested for continuity. A
separate circuit protective conductor, of minimum size 1.5mm² with green insulation, shall be installed in all PVC
conduits.
Steel conduits and accessories shall be protected from the weather both during storage and erection.
B1.2
Flexible conduit
Flexible conduit shall be of the overlapping helically wound flexible steel type with PVC outer cover
manufactured in accordance with BS 731, unless otherwise specified within the particular specification part C.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
The flexible conduit shall be fitted with heavy duty couplers and connections with male threads to BS 4568.
They shall include a special bush to protect cables when drawn in.
The internal bore of conduit and all fittings shall be free from burrs and defects.
Flexible conduit connectors to equipment shall be kept as short as possible but installed and supported to
ensure there is no strain on couplings or conduit.
An insulated circuit protective conductor of minimum size 2.5mm 2 shall be run in the flexible conduit and
connected to the earth terminal of the fixed conduit system and supplied equipment.
B1.3
Cable trunking
B1.3.1
General
Trunking systems enclosing cables shall form a continuous enclosure providing mechanical protection, and be
of sufficient size to accommodate the cables in accordance with the BS 7671 (IEE Regulations).
The type of trunking to be used shall be as detailed in the Particular Specification Part C and will be either:i)
Heavy gauge galvanised sheet steel to BS 4678 Part 1: Steel Surface Trunking
ii)
Heavy gauge high impact, rigid self extinguishing UPVC to B4678: Part 4: Cable Trunking made of
insulating material.
The lid to steel trunking shall be fixed by means of an internal clamping member, secured by large headed
turnbuckles, in such manner that cable will not become pinched or trapped. Fixing by means of tapped screws
to the flange of the trunking will not be accepted.
Lids to the UPVC trunking shall be of the type that snap positively into position with no exposed fixings, and
shall require the removal of lids to fittings, before one end of the trunking lid can be accessed for removal.
Trunking shall be supplied with all necessary angle, tee and four way junction pieces, coupling pieces and
blanking off plates as supplied by the trunking manufacturer. Where partitioned trunking is used the partitioning
shall be maintained at intersections and angle pieces. The finish of fittings shall match that of the particular
trunking which is being used.
External copper earth links shall be provided on the side of each length of steel trunking to maintain electrical
continuity.
B1.3.2
Installation
Care shall be taken to ensure that trunking runs are fully planned, in consideration of building features and other
services before work is commenced.
The Contractor shall ensure that all trunking is fixed plumb in either vertical or horizontal directions, except
where it is desirable to follow the line of a constructional feature.
The cable trunking shall be fixed at intervals not exceeding those specified by the manufacturer and indicated in
the BS7671 (IEE Regulations). The method of fixing shall depend upon the nature of the surface to which it is
secured.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Where the cable trunking is fixed vertically for a distance of more than 3 metres the Contractor shall supply and
install purpose made pin racks to support the cable. In cable trunking having a dimension of 100mm and above
in any direction, spacing pins shall be fixed by the Contractor to ensure neat cable runs to facilitate the tracing of
circuits.
Fire barriers shall be supplied and installed in all vertically installed trunking at all floor levels or 5 m centres
whichever is the lesser.
Non-metallic trunking shall not be used to pass cables through fire barrier walls or floors. Steel trunking shall be
inserted in the non-metallic trunking run, being installed to 300mm clear of both sides of the barrier.
Conduit entries into trunking shall be by coupler and male, bush, plain holes or grommetted holes will not be
allowed.
Cables leaving trunking shall do so through holes or slots bushed to prevent abrasion of the sheathing.
A pattress of suitable non-combustible material shall be fitted between the flange of the trunking and a cable
entry to metal cased equipment. The slot in the pattress, which shall have bevelled edges, shall be smaller that
that in the equipment to prevent chafing the cables.
Holes made in trunking shall be neatly made and uniform, shall be filed or reamered to remove ragged, burred
or sharp edges.
Whenever practicable, the trunking manufacturers standard fittings shall be used, special fittings that have to be
fabricated shall be properly made, fastening by self tap screws will not be allowed. After fabrication special
fittings for metal trunking shall be painted or galvanised to the same standard as the manufactured trunking.
The Contractors attention is drawn to the need for expansion allowances at 3 metres intervals in UPVC trunking.
The size of any trunking shall be such that it will accommodate the cables to be installed and make 25%
allowance for future cables from spare fuseways etc. The size of the trunking shall make due allowance for the
reduced section at flyovers of multi-compartment trunking. Circuit protective conductors shall be included in the
calculation to ascertain the minimum trunking size.
The lids (covers) of the trunking shall be securely fixed along the entire length of the run. Trunking lid cut to
length shall be provided with additional fixings within 150mm of the end of the lid.
Except where it is necessary at a change of direction the trunking lid shall not be weakened by cutting or
reducing the return edge.
The lids of trunking at the point of passing through walls or partitions that will be in position at the time of
practical completion shall be separate and not extend more than 300mm from that wall or partition.
Inverted trunking shall be provided with cable retaining straps.
Trunking and accessories shall be protected from the weather both during storage and installation.
Care shall be taken to ensure that trunking installed during the progress of the building works is protected from
damage by other trades and that building materials do not enter trunking and the accessories.
Care shall be taken to avoid damaging finished, surfaces, protecting enamel or galvanising. Any damage that
does occur to steel trunking shall be coated with a matching paint finish enamel immediately after erection.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Self finished surfaces shall be protected from damage during the installation period and carefully cleaned on
completion of the contract by the Contractor.
B1.3.3.
Ceiling and overhead trunking
Ceiling and overhead trunking shall be installed to levels and grid datum provided at regular intervals by the
Main Contractor. Where trunking is to be incorporated in the ceiling, the Contractor shall work in close cooperation with the ceiling erector and other trades also incorporating their service in or above the ceiling.
Where PVC trunking, mini trunking, or lighting trunking with PVC lids are installed either surface across ceiling
or above suspended ceilings, the cables shall be securely fixed by metal cable retainer every 1.5m securely
fixed to the building fabric in addition to the requirements of BS7671 to prevent cables falling in the event of fire
situations.
B1.3.4.
Lighting trunking
Lighting Trunking shall be complete with suspension stirrups - luminaire suspensions, and cover strip. Trunking
suspensions shall be at centres not more than required by the Particular Specification Part C and/or the
manufacturers recommendation.
Where PVC trunking, mini trunking, or lighting trunking with PVC lids are installed either surface across ceiling
or above suspended ceilings, the cables shall be securely fixed by metal cable retainer every 1.5m securely
fixed to the building fabric in addition to the requirements of BS7671 to prevent cables falling in the event of fire
situations.
B1.3.5
Floor trunking
Floor trunking shall be installed to levels provided at regular distances by the Main Contractor. The floor
trunking shall be installed in the manner described in the Particular Specification Part C.
The Contractor shall work in close co-operation with the Main Contractor and ensure that the trunking is
securely fixed to the floor slab and will not dislodge during the floor laying operation. The Contractor will be
responsible for the accuracy in level (to the datum provided) of the trunking, its access and service outlet,
boxes, etc.
B1.4
Bench and skirting trunking
Bench and skirting trunking shall be of the type and pattern as described in the Particular Specification Part C.
Generally this type of trunking shall be compartmented for the installation of and segregation of different
electrical and communications wiring systems.
The requirements for fittings, fixings and installation as Clause B1.3. shall equally apply to this type of trunking.
When fixing skirting trunking to the wall prior to a floor finish or covering being fitted, sufficient clearance spaces
below the trunking shall be allowed for the floor covering to be fitted underneath. When the floor covering is
already in position the trunking should be mounted flush with the covering.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Bench trunking unless specifically required, shall not have its fixings direct into the bench or worktop, but shall
be fixed independently into the wall or partition.
B1.5
Rising busbar trunking
Rising busbar trunking shall be manufactured from sheet steel in accordance with BSEN60439-1: Low voltage
switchgear assemblies and BS5486 Part 2: Requirements for busbar and partially type-tested assemblies and
BS5486 Part 2: Requirements for busbar trunking systems and shall be stove enamelled or galvanised as
specified.
Each length of trunking shall be complete with all mechanical and electrical connections fixing brackets and
coupling bolts.
The busbar riser covers shall be fixed with screws at each side of the busbar section. At each distribution board
take-off position for each floor there shall be a fused tap-off unit.
Busbars shall be copper, suitable for the current rating and fault rating specified. High grade insulating panels
shall be spaced at frequent intervals to support the busbars and withstand the stresses set up under short circuit
conditions. The neutral conductor shall be of the same cross sectional area as the phase conductors and under
no circumstances must the conductors be reduced at take off points.
At the bottom of the riser, a set of thrust blocks shall be incorporated to secure and support the busbar
conductors. Provision shall be made for expansion of the busbars.
Where trunking rises vertically through floors it shall be fitted with internal fire barriers in accordance with
BS7671 (IEE Regulations).
A heavy gauge sheet steel cable entry unit shall be fitted to the bottom of each riser complete with removable
cover to suit the type of cable specified.
B1.6
Cable tray, cable-basket and cable ladder
The cable tray shall be perforated, complete with couplings, preformed sets, bends, brackets and spacers.
Cable tray shall be of the type and pattern as specified in Part C Particular Specification.
Cable basket shall be manufactured in pre-galvanised steel with zinc coating as detailed in Part C Particular
Specification.
With the agreement of the Engineer, cable tray/cable basket not otherwise specified may be installed by the
Contractor without additional cost to facilitate the installation of the cables that are part of the Contract.
All cable tray/cable basket used shall be of sufficient gauge to ensure that it is rigid when erected, will not easily
deform and will not spring from its original shape.
Fixings and supports to the cable tray/cable basket shall be in accordance with the manufacturers
recommendations. Care shall be taken to ensure that the routes are fully planned in consideration of building
features and other services before work is commenced.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Bends and sets shall, wherever possible, be provided as a standard item by the Manufacturer of the cable
tray/cable basket and shall have the same finish. Special fittings that have to be fabricated shall be properly
made, fastening by self tap screws will not be allowed. After fabrication special fittings shall be painted or
galvanised to the same standard as the manufactured cable tray/cable basket. When it is necessary to cut
cable tray/cable basket to length, the cut shall be made to avoid perforations, the ends removed of all sharp
edges or burrs and be painted with rust inhibiting paint.
Cable tray/cable basket together with its fixings installed in external or damp situations shall be hot dip
galvanised, PVC dipped or of UPVC construction.
Cable tray/cable basket in dry situations may be sheridized or zinc plated.
Where cable trays/cable baskets rise vertically through floors, or run horizontally through fire partitions, the
contractor is to provide the necessary fire barriers in accordance with BS 7671 (IEE Regulations).
Cables shall be fixed with proprietary saddles, clips or cable ties.
All electrical services contained on inverted cable trays, cable basket, cable ladder, catenary wire or clipped
direct to the underside of ceilings and soffits shall be affixed to the aforementioned containment with metallic
cable ties or metallic proprietary clips every 1.5m in addition to the fixing requirements of BS7671 to prevent
cables falling in the event of fire.
Care shall be taken to avoid damaging finished surfaces. Any minor damage that does occur shall be suitably
coated immediately after erection. Lengths of tray/basket which sustain damage which is more than minor shall
be replaced. The Engineer shall be informed of any damage that is sustained and the instructions on the
remedial action to be taken shall be final.
Lengths of cable tray shall be coupled by mushroom headed bolts, nuts and shake proof washers. The head of
the bolt shall be fitted on the side of the Cable Tray on which the cables are fixed. Lengths of cable basket shall
be coupled in accordance with manufacturer‟s requirements and fixings.
Precautions must be taken to ensure that electrolytic action caused by dissimilar metals coming into contact is
avoided.
Care must be taken to ensure that earth continuity is maintained throughout the system; earth straps shall be
fitted at each joint on the outer face where the strap can be readily examined.
Cable tray/cable basket and accessories shall be protected from the weather both during storage and
installation.
Care shall be taken to ensure that cable tray/cable basket installed during the progress of the building works is
protected from damage by other trades.
B1.7
Colour coding and identification of conduits/trunking and
conductors
B1.7.1
General
Where colour coding and identification of conduits/trunking is required by the particular specification, this shall
be in accordance with regulations 514 of BS7671 (IEE Regulations) Identification of pipelines and services.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
B1.7.2
Identification of conductors
In order to harmonise cable colours, an alpha-numeric identification system for fixed electrical wiring, in line with
BS7671:2008 Appendix 7 shall be adopted; the contractor shall supply and install using the following core
identification system.
The principle to be adopted by the contractor is that cable cores should be identifiable at their termination, by
either:


Colour or
Numbering/lettering
Where colour is used to comply with the method of identification, the table below gives the colour options.
Table 7 – example of conductor marking at the interface for additions and alterations to an installation identified
with the old cable colours
Old conductor
New Conductor
Function
Colour
Marking
Colour
Marking
(1)
Phase 1 of AC
Red
L1
Browm
L1
(1)
Phase 2 of AC
Yellow
L2
Black
L2
(1)
Phase 3 of AC
Blue
L3
Grey
L3
Neutral of AC
Black
N
Blue
N
Protective conductor
Green & yellow
Green & yellow
(1)
Three single-core cables with insulation of the same colour may be used if the identified at the terminations.
Table 7 – Cable to BS 6004 (flat cable with bare cpc)
Cable type
Old core colours
Single-core + bare cpc
Red or black
Two-core + bare cpc
Red, black
Alt. two –core + bare cpc
Red, rad
Three-core + bare cpc
Red, yellow, blue
New core colours
Brown or blue
Brown, blue
Brown, brown
Brown, black, grey
Table 7 – Standard 600/1000V armoured cable BS6346, BS5467 or BS6724
Cable type
Old core colours
New core colours
Single-core
Red or black
Brown or blue
Two-core
Red, black
Brown, blue
Three-core
Red, yellow, blue
Brown, black, grey
Four-core
Red, yellow, blue, black
Brown, black, grey, blue
Five-core
Red, yellow, blue, black, greenBrown, black, grey, blue, greenand-yellow
and-yellow
Table 7 – Flexible cable to BS6500
Cable type
Two-core
Three-core
Four-core
Old core colours
New core colours
Brown, blue
Brown, blue, green-and-yellow
Black, blue, brown, green and
yellow
No change
No change
Brown, black, grey, green-andyellow
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Table 7 – Flexible cable to BS6500
Five-core
Black, blue, brown, black, greenand-yellow
Brown, black, grey, blue, greenand-yellow
Table 7 – Example of conductor marking at the interface of additions and alterations to DC installation identified
with the old cable colours
Old conductor
New conductor
Function
Colour
Marking
Marking
Colour
Two-wire unearthed DC power circuit
Positive of two-wire circuit
Red
L+
L+
Brown
Negative of two-wire circuit
Black
LLGrey
Two-wire earthed DC power circuit
Positive (of negative earthed) circuit
Negative (of negative earthed) circuit
Positive (of positive earthed) circuit
Negative (of positive earthed) circuit
Red
Black
Black
Blue
L+
M
M
L-
L+
M
M
L-
Brown
Blue
Blue
Grey
Three-wire DC power circuit
Outer positive of two-wire circuit
derived from three-wire system
Red
L+
L+
Brown
Red
Red
Black
Blue
LL+
M
L-
LL+
M
L-
Grey
Brown
Blue
Grey
Outer negative of two-wire circuit
derived from three-wire system
Positive of three-wire circuit
Mid-wire of three-wire circuit
Negative of three-wire circuit
Identification by numbering or lettering
Where conductors are numbered, to satisfy other part of BS7671, a suitable wiring diagram or equivalent will be
supplied by the Contractor indicating the use of the numbers.
Alterations, additions and refurbishments
Subject to the availability of cable types, an extension (alteration/addition) shall be identified using either
identification method. After 1 April 2006 all new installations shall be to the harmonised colour or
lettering/numbering in accordance with Amendment No 2, BS7671.
Where pre-harmonised and harmonised cables are used in the same installation the following label shall be
applied by the contractor at the relevant distribution boards or items of switchgear as appropriate.
Caution
This installation has wiring colours to two versions of BS7671. Great care should be taken before undertaking
extension, alteration or repair that all conductors are correctly identified.
B1.8
Service ducts, trenches & tunnels
B1.8.1
General
Duct, trench or tunnel accommodation shall make possible the planned site services to be installed with
adequate clearances and also include space for possible future requirements.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
As far as is practicable, ducts or trenches for the accommodation of electrical cables will not be used by other
services. Where it is necessary to accommodate electrical cables with other services there should be adequate
route separation between those services & electrical cables or conduits. The electrical cables shall be installed
in the supper space of a trench or tunnel to minimise the possibility of damage from water. HV cables must not
be routed in enclosed areas close to flammable gas or oxygen pipework.
When sizing ducts, trenches or tunnels, maintenance access shall be considered.
Provision of an electrical supply for SELV lighting at manholes or access tunnel entrances and connection of
portable ventilation is required.
Where HV cables are installed, they shall be identified with „DANGER‟ ……… volts‟ notices provide at points
where access to HV cables can be obtained. Exposed cable installation must always be protected from
mechanical damage by barriers, covers or space.
Lift shafts shall not be utilised for the accommodation any other services which are not part of the lift installation.
Construction
Floor for trenches etc shall be constructed of concrete & have a slight fall & a shallow drainage channel with
drainage points at suitable intervals. The sides and top covers shall be constructed of concrete. Vertical cable
ducts or flumes will be installed with fire barriers at each floor.
Access openings shall be large enough to enable standard 3M lengths of conduit to be installed and removed
without bending and shall be kept clear of conduits/cables.
External cable routes
The contractor shall b e responsible for the correct measurement on site of the cable lengths required, and they
shall be installed in one continuous length without any through joints.
Where cables are laid in the ground the Contractor shall ensure that trenches, pits and ducts are to his
satisfaction before cables are laid.
Care shall be taken when excavating the trench to avoid damage to other services. Reference shall be made to
site drawings showing services to ascertain the possible locations of other services. Should any damage occur,
the Engineer shall be informed immediately.
Other services and cables that are uncovered shall be adequately supported and protected.
Cables buried in the ground shall be laid in properly excavated trenches 600mm deep. The trenches shall be
evenly graded, clear of loose stones and coved with a 75mm layer of sand or sifted soil. The cables shall be
carefully laid in the trench being spaced apart where there is more than one and a 75mm layer of sand sifted
soil placed over the cables before the trench is back filled.
All buried cable routes shall be provided with heavy gauge plastic warning tapes 250mm above each cable
running the full length of the cable route and shall be supplied by the Contractor. The tapes shall be red for HV
and yellow for LV and not less than 150mm wide and 0.1mm thick bearing the legend „Electric Cable Below‟ in
black letters. Such tapes shall be of a PVC material resistant to the acids/alkalis that may be encountered in the
ground on site.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Where cables are laid in open ground, they shall be located by indestructible cable markers placed not more
than 25M apart and at a point where the cable changes direction. Cable markers shall be attached to
permanent walls in positions to be agreed to indicate where cables enter/leave a building. All markers shall give
adequate information to locate the cable. All cable markers shall be supplied and installed by the Contractor.
On main cable routes where additional cables may subsequently be required, spare cable ducts or trench space
shall be provided. Access holes shall be provided for entry into cable tunnels or ducts.
Cable ducts shall be used for all points where cables enter buildings, they shall be installed using easy bends
finishing flush with the finished floor level. The entry points into buildings are to be sealed by caulking and
finished with a 1:3 cement/sand mix after cable laying to prevent the passage of moisture or vermin. Care
should be taken when drawing in cables to ensure that undue stress or strain is not placed on the cable.
Cable ducts shall also be used where the cable routes pass under roads or other permanent made-up surface
(hard dig). Where the cable routes pass under roads the ducts shall be encased in concrete to prevent fracture
by traffic. In the ducting network draw-pits/access holes shall be installed at every change of direction and
every 50M. A spare capacity of 25% shall be allowed for future requirements.
Cable ducts shall be a minimum of 100mm diameter and made in rigid PVC tube and:
a)
The buried ducts bending radius may be formed by interconnecting angled socket couplings to obtain
the required angle of curvature;
b)
Each tube shall have a plain spigot at one end and a sealing socket in the other end for making a
watertight push fit;
c)
Access-holes/draw pits shall have drainage and be of a adequate dimensions for cable pulling;
d)
The clearway and alignment of the cable ducts shall be proved to the Engineer by pulling through an
approved test piece prior to the enclosing concrete has hardened;
e)
The load bearing cable ducts shall be immersed in concrete of depth/width to provide a minimum cover
of 150mm above and below and 100mm on each side of the sockets. The ducts must be secured to
prevent floatation during the pouring of the concrete;
f)
PVC tube must be stored horizontally and out of direct sunlight;
g)
The recommended minimum buried depths for external cable installations are:
i
ii
Low voltage cables – 0.6M;
High voltage cable - 0.8M.
All trenching, reinstatement, supply of sand, ducts and installation of ducts will be carried out by the Main
Contractor unless otherwise specified in Part C Particular Specification.
Cable plan
A plan print drawing depicting accurately the position of all the external cable runs, ducts and trenches together
with all the external drainage facilities, incoming gas mains and incoming water main shall be supplied upon
completion of the works for submission into the O&M manuals.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
B1.9
Catenary wire support
Catenary wire and its fixings shall be manufactured in stainless steel. The catenary wire shall be of minimum 16
SWG. The catenary wire and its relevant fixings shall be adequately sized to accommodate 125% of the load of
the cable and its fixings to the catenary wire. All catenary wires will be suitable earthed. Cables shall be
secured to catenary wire using fixing method described in clause B1.6.
The maximum lengths of span and minimum installation heights above the ground for overhead wiring between
buildings etc. using catenary wires shall be as follows:
Cables sheathed with plastics or having oil-resisting and flame retardant (hofr) sheath, supported by a catenary
wire has no limit to length of span, but a minimum of 5.8M height in positions accessible to traffic and at road
crossings. Where installed in positions inaccessible to vehicular traffic the minimum height is 3.5M.
Overhead cables incorporating a catenary wire has a limit to length of span between supports as recommended
by the manufacturer, and a minimum of 5.8M height in positions accessible to traffic and at road crossings.
Where installed in positions inaccessible to vehicular traffic the minimum height is 3.5M.
B1.10
Cables concealed within wall
Cable concealed within walls and patent hollow partitions shall be installed using one of the following methods:
Compliance with Regulations 522.6.6 of BS7671 2008 within all HCC Properties.
All cable concealed within a wall or partition at a depth less than 50mm shall be protected by:
1
Enclosing the cables within an earthed metallic conduit to BS EN 61386
This method shall be the preferred installation method, however if this cannot be achieved then the following
alternative methods can be employed:
2
Utilise a cable incorporating an earthed metallic covering which complies with BS5467, BS6346,
BS6724, BS7846, BS EN 60702-1 or BS8436. Where these cables are used on lighting circuit switch
drops the cable shall be taken back to the ceiling rose/Klik connector, no additional junction boxes will
be acceptable.
Where these cables are used for circuits other than switch drops the cable shall emanate from the
source of the circuit, no junction boxes will be permitted. If this installation method is used all cable
shall be installed within plastic conduit within walls/partitions to ease the rewiring of the circuit.
3
If it is not practical to achieve either of the methods above the cable shall be installed surface within
trunking/conduit.
If its not possible to achieve methods 1-3 above then the cable shall be protects by means of an RCD
with a rating not exceeding 30mA. To avoid the possibility of nuisance tripping, the use of RCD;s on
lighting circuits should be avoided as far as is practically possible.
All socket outlets, with the exception of those serving fridge freezers, data cabinets, telephone equipment, fire
and intruder alarm systems or any other specialist equipment, shall be clearly labelled to identify which
equipment they are dedicated to supply. Where no RCD protection is afforded then one of the above cable
installation methods shall be utilised.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
The conduit shall project into the floor or ceiling space when accommodating cables from that space.
B1.11
PVC covered single core cables
PVC insulated cables shall be high conductivity copper wire insulated with polyvinyl chloride compound
600/1000V grade ref 6491HB (OHLS). They shall be by an approved BASEC manufacturer and shall comply
with BS 6004 - 1969 Table 5.
Heat resisting copper conductors 600/1000V grade are to be used where called for in of the specification and
drawings.
Cables shall be coloured in accordance with regulation 514 and Tables 51 of BS7671 (IEE Regulations).
Cables of less than cross sectional area 1.5mm² shall not be used and conductors shall be stranded.
B1.12
PVC covered single core cable installation
All single core cables, with the exception of protective conductors or double insulated meter tails shall be
protected throughout their entire length by conduit, trunking boxes or switchgear enclosures.
Cables shall not be drawn into any section of a conduit, trunking or ducting system until that section of the
system is complete.
All cables of a circuit shall be drawn into the same conduit or trunking system simultaneously neatly without
kinks, bends, twists or crossovers.
When cables are installed in trunking, ducting or floor ducting, all cables comprising one circuit shall be bound
together, and clearly identified.
The number of cables installed in any trunking or conduit shall not exceed the recommendations detailed in the
IEE Regulations, and the voltage drop shall not exceed the limits specified in clause 525 of BS7671 (IEE
Regulations).
Wiring shall be carried out as the „looping in and out‟ system and not more than three cables shall be connected
to any one termination point.
All cables shall be threaded or drawn into conduits without undue tension or strain, and shall be easily
withdrawn. Cable drums shall be supported on a tripod when wiring, to avoid damage to cables. Damaged
cables will be rejected and shall be replaced at the Contractors own expense.
The Contractor shall ensure cables are adequately protected from damage by other trades during installation.
B1.13
PVC insulated and sheathed cables
PVC insulated and sheathed cable shall be high conductivity copper wires insulated with polyvinyl chloride
compound. The cores shall be laid flat and sheathed with polyvinyl chloride compound, and shall be of the
600/1000 volt grade Ref 6242B and 6243HB (OHLS) and comply with BS 6004 and be an approved BASEC
Manufacturer.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Cables with conductors of less than 1.5mm² shall not be used. Cables above 2.5mm² shall have stranded
conductors.
All PVC insulated and sheathed cables shall include a Circuit Protective conductor.
Cables shall be coloured in accordance with regulation 514 and table 51 of BS7671 (IEE Regulations), and the
CPC provided with a green/yellow sleeve when terminated.
PVC insulated and sheathed cables shall be used on single phase circuits only.
B1.14
Installation of PVC insulated and sheathed cables
The route and location of cables shall be carefully chosen to avoid the cables being in contact with heating
pipes, and thermal insulation particularly expanded Polystyrene which may cause migration of the PVC
plasticiser in the cable.
Care shall also be taken to protect cable sheaths from the solvents of preservatives and other treatments newly
applied to timber.
Cables installed in roofs, ceilings and floor spaces shall run parallel or at right angles to the joists and shall be
fixed using plastic wiring clips with hardened steel pins.
Where cables are installed in wooden floor structures, they shall be run in such a position that they are not liable
to damage by contact with the floor or fixings. Where a cable traverses wooden joists it shall run in holes drilled
in the joist which are a minimum of 50 mm from the top or bottom of the joist. Alternatively the cable shall be
protected by enclosure in steel conduit, securely fixed and bushed.
Cables on fair faced walls, unless specified otherwise in Part C Particular Specification, shall be enclosed in
heavy gauge high impact PVC conduit or in trunking. The conduit or trunking shall project into the floor or
ceiling space when accommodating cables from that space.
Cable or group of cables installed on centenary wire shall be neatly bunched and secured to the catenary with
PVC metallic cable ties at intervals not exceeding 450 mm. PVC tape will not be acceptable.
Cables installed on cable tray/basket shall be neatly installed to avoid cables tangling. Cables shall be securely
fixed to the tray/basket by means of patent cable ties. Cable basket/tray passing through fire walls/floors shall
be suitably fire stopped.
Where conduit take offs are required, these shall be carried out using cable basket/tray manufactures purpose
made adaptors.
No joints will be permitted in any cable run, junction boxes will not be used in any lighting or power circuit. All
cable interconnections shall be carried out in socket outlets, ceiling roses and other accessories.
Where cable pass through walls, floors, steelwork, etc., they shall be protected by steel or plastic conduit
adequately bushed at each end. Galvanised steel conduit/trunking shall be used when passing through fire
walls/floors and shall be suitably fire stopped.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
B1.15
MICC cables
B1.15.1
General
Mineral insulated copper covered cables shall be manufactured to BS 6207-1. They shall be light duty 600V
class or heavy duty 1000V class as indicated in the specification or drawing and be by an approved BASEC
manufacturer.
Where required in the Particular Specification Part C or drawings MICC cables shall be supplied with an overall
orange PVC sheath. For fire alarm installations the sheath shall be red. Where PVC sheathed MICC cables
are installed all terminations shall be provided with a PVC shroud unless otherwise specified.
All MICC cables shall terminate in an approved type of cold screw on pot seal and connection to switchgear,
conduit fittings and accessories shall be made with a ring type compression gland. Pot only seals where
particularly specified or with the approval of the Engineer shall be of the type with an earth tail.
Cable tails shall be insulated with sleeving of the neoprene type the sleeving shall be secured and sealed into
the pot type seal. Sleeving shall be coloured in accordance with BS7671 (IEE Regulation) Table 51.
Each length of cable shall be tested after the seals have been fitted. Insulation resistances below infinity will not
be accepted.
MICC cables shall be terminated and installed strictly in accordance with the manufacturers recommendations,
BS6207-2 Fittings for mineral insulated cable, and only by electricians experienced in this type of cable
installation. Only the tools supplied by the cable manufacturer for the necessary cutting and making of cable
ends shall be used.
B1.15.2
Installation
The cables shall be run in a neat and workmanlike manner, and as far as is practical, in straight or symmetrical
lines. Individual runs shall be carefully chosen to avoid other services. Surface runs on walls shall be horizontal
and vertical, sited close into building features to aid concealment and render possible additional protection.
In MICC cable installations, care shall be taken to avoid electrolytic action between dissimilar metals damaging
the sheath of the metal cable. Bushes, saddles, glands and non-ferrous conduit fittings shall be of the same
material, or if any alloy, be of the same base metal as the cable sheath.
All cable runs, unless specific permission is given, shall be continuous throughout. No joints will be allowed.
The cable shall not touch any pipes and shall in all cases be at least 50 mm from heating pipes. No cable bend
shall have an internal radius of less than twice the overall diameter of the respective cable. Saddles shall be of
the same material as the cable sheath and fixed by non-ferrous screws and spaced at distances of not more
than spacing laid down in Table 11A of the IEE Regulations. The Contractor shall make certain that all MICC
glands are stamped with the correct reference number to denote the size of cable and the number of cores.
The Contractor shall supply all cable glands required for the connection of MICC cable to equipment, regardless
of the suppliers of that equipment.
MICC cables shall not be run within floor screeds, except with the express approval of the Engineer. Where
approval is given, they shall be installed within a PVC conduit a minimum 25 mm diameter.
Where cables are installed in roof and floor voids they shall be run and protected in the same manner as
described for PVC/PVC cables under clause B1.13.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
When several cables are run together multiple saddles shall be used.
Cable tray shall be used to support cables where multiple runs occur in plant rooms, roof and floor spaces,
ducts and crawl ways. Galvanised cable trays shall not be used for cables having bare copper sheaths.
MICC cables installed externally, or in damp situations, shall have a PVC over sheath. MICC cables concealed
within walls or partitions shall be installed within heavy gauge UPVC conduit.
Suitable protection shall be provided where cables are installed externally below 2 metres in height or in areas
subject to a high risk of mechanical damage. MICC cables shall not be installed directly into the ground.
B1.16
Fire resistant cables
B1.16.1
General
Fire resistant cable 300/500 V class shall be installed principally for Fire Alarm, and Emergency Lighting
installations, unless otherwise specified.
The cable shall comprise copper conductors insulated with silicone rubber, tinned copper circuit protective
conductor, aluminium foil screen and thermoplastic outer sheath.
Cable shall be designed to meet the following standards:BS5839 - Pt 1 (latest edition) - Fire detection and alarm systems in buildings
BS5266 - Pt 1 (latest edition) - Codes of practice for emergency lighting
BSEN1838 - (latest edition)
BS6387 - Performance requirements for cables required to maintain circuit integrity under fire conditions
BS4066-1 - Tests on electrical cables under fire conditions
B1.16.2
Installation
The cables shall be run in a neat and workmanlike manner, and as far as is practical, in straight or symmetrical
lines.
Care shall be taken when terminating the cables, to ensure that the silicone rubber insulation is not damaged,
and the manufacturers recommendations are followed. When necessary ferrules shall be fitted and the cables
must be terminated using PVC compression glands of same colour of cable.
Cables shall be fixed using PVC coated saddles of same colour as cable secured with non ferrous screws. The
distance between fixing saddles shall not be greater than laid down in BS7671 (IEE Regulations). Cable bend
shall have a minimum radius of six times the cable diameter.
No joints will be permitted in a cable run all interconnections shall be made at switchgear, lighting or accessory
positions.
Cables shall not be run in floor screeds without the express permission of the Engineer. Where this permission
is given the cable shall first be enclosed within high impact heavy gauge UPVC conduit.
Where the cables are run in floor and roof voids, the same care and protection required in clause B1.13 shall
apply.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
B1.17
Flexible cables
Flexible cables for lighting installations shall be manufactured in accordance with BSS 6500 by an approved
BASEC manufacturer. No flexible cable less than 0.75mm² shall be used. Flexes for plain pendants up to 200w
shall be 0.75mm² PVC insulated with an overall circular white PVC sheath heat resisting to BS 6500 table Ref:
7.1.
The maximum weight of luminaire which may be supported by the flexible cable of not less than 0.75mm² is 3 kg
in accordance with BS7671(IEE Regulations) Table 4H3A.
No flexible cable shall be run where it is concealed. Flexible cables installed where they are subject to heat and
in enclosed fittings shall be of the BSS 6500 table reference 8.2.
Flexible cables for portable appliances exceeding 200 watt load shall be 2 or 3 core as required and not less
than 32/0.20 mm² vulcanised rubber insulated TRS or PCP sheathed. Cables shall comply with BS6500 table
reference 5.4.
Flexible cables shall be coloured in accordance with BS7671 (IEE Regulations).
Connections between flexible and hard conductors shall be single or multi-way heat resisting pinch screw type
conductors.
The Contractor shall ensure that the current rating of the cable is such, that it will be fully protected by local
fusing or the final sub-circuit fuse or MCB.
B1.18
XLPE and PVC armoured cables
B1.18.1
General
XLPE and PVC insulated cables shall be 600/1000 volt grade to BS 5467 for XLPE and BS 6346 for PVC as
produced by a BASEC manufacturer.
Cables shall have a neutral conductor of the same cross sectional area as the phase conductor and shall be
one of the following as specified in the Particular Specification Part C and the Contract Drawings.
i)
Copper conductors of high conductivity wire, insulated with either polyvinyl chloride (PVC) or cross
linked polyethylene (XLPE).
The conductors shall be laid up and sheathed with PVC tape to provide a bedding. The armour shall consist of
a single layer of galvanised steel wire or tape and the cable sheathed overall with PVC.
ii)
Solid aluminium shaped conductors, insulated with either PVC or XLPE, laid up and sheathed with PVC
tape or extrusion to provide a bedding. The armour shall consist of a concentric layer of hard drawn
aluminium strips or single layer of galvanised steel wire. The cable shall be sheathed overall with PVC.
iii)
Where single core armoured cables are used, the armouring shall be manufactured from aluminium.
B1.18.2
Installation
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
i)
Cables in ground
Cable routes shall be as shown on the drawings and the Contractor shall base his tender on the information
provided. He shall however make allowance for changes in level and deviations required by following the
building profile.
The contractor shall be responsible for the correct measurement on site of the cable lengths required, and they
shall be installed in one continuous length without any through joints.
Where cables are laid in the ground the Contractor shall ensure that trenches, pits and ducts are in accordance
with Clause B1.8 and to the contractor‟s/engineer‟s satisfaction before cables are laid.
Care shall be taken when excavating the trench to avoid damage to other services. Reference shall be made to
site drawings showing services to ascertain the possible locations of other services. Should any damage occur,
the Engineer shall be informed immediately.
Other services and cables that are uncovered shall be adequately supported and protected.
Cables buried in the ground shall be laid in properly excavated trenches 600mm deep. The trenches shall be
evenly graded, clear of loose stones and covered with a 75mm layer of sand. The cables shall be carefully laid
in the trench being spaced apart where there is more than one and a 75mm layer of sand placed over the
cables before the trench is back filled.
A heavy gauge yellow plastic warning tape shall be placed 250mm above each cable running the full length of
the cable route and shall be provided by the Contractor.
Where cables are laid in open ground, they shall be located by indestructible cable markers placed not more
than 25mm apart and at a point where the cable changes direction. Cable markers shall be attached to
permanent walls in positions to be agreed to indicate where cables enter/leave a building. All markers shall give
adequate information to locate the cable. All cable markers shall be supplied and installed by the Contractor.
Cables crossing under concrete, asphalt or tarmacadam roadways, footpaths or made up areas shall be
enclosed in approved ducts not less than 100mm in diameter.
Entries into buildings shall be by ducts not less than 100mm with easy bends terminating flush with the finished
floor level at an agreed position in the building. After the cable has been drawn into the duct, the duct shall be
sealed within a suitable material which can be removed. Care shall be taken when drawing in cables to ensure
that undue stress or strain is not placed on the cable.
All trenching, reinstatement, supply of sand, ducts and installation of ducts will be carried out by the Main
Contractor unless otherwise specified in Part C Particular Specification.
The exact location of underground, ducted or concealed cables shall be carefully recorded at the time of
installation. The precise route shall be indicated clearly on the record drawings which shall include dimensions
from permanent features of each changes of direction and depth of services.
ii)
Cables within buildings
The route of cables through buildings shall be considered carefully, to ensure that there is no conflict with other
services.
Cables run in ducts accommodating heating pipes shall be run in the lower part.
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Part B: Materials and workmanship
Section B1: Materials
Where other services are crossed, they shall be run below rather than above the other services and, if by
reason of layout, they do run above heating pipes etc., they shall be supported by cable hangers the complete
length of the traverse.
No cable shall be drawn through continuous ducts for a greater length than 50 metres. Suitable pits for drawing
in must be provided and at all changes of direction.
Cables passing through walls, partitions, floors, and ceilings shall do so in a manner that is to the approval of
the Contract Administrator.
Holes shall be carefully formed, and sleeved to prevent abrasion to the cable. Care shall be taken to ensure
that the cable is supported either side of the wall/partition and that no load is imposed by the cable passing
through. After the cable is installed, the hole shall be made good with a material that is not corrosive to the
armouring or the sheath of the cable.
Holes for cables passing through part of the structure that are barriers separating fire compartments shall be
formed with particular care, ensuring that the holes are not larger than is necessary to allow the cable to be
installed and the hole made good by packing with non-combustible non-corrosive intumescent material.
Where cables are installed through accessible ceiling, roof and floor voids, the cables shall have durable, heavy
gauge PVC cable markers attached at 2 metre centres throughout the length of run. The markers shall denote
the function of the cable ie. Lighting and power sub-main and the equipment served ie Disboard 'A' 3phase, being written on the markers with an indelible pen.
Cable tray/basket or rack shall be provided for the support cables as specified in Part C Particular Specification
and on the contract drawings.
If the tray/basket or rack does directly support the cables they may be retained in position by nylon cable ties.
If the tray/basket or rack does not directly support the cables, the cables shall be fixed by cleats completely
surrounding the cable, bolted to the cable tray or rack.
Cables fixed directly to walls etc. shall be supported by cleats which completely surround the cable and are
fixed' to the wall by bolts or screws into patent wall plugs at spacings not exceeding those laid down in table
11A of the IEE Regulations.
Any bends in cables shall have a radius of not less than that recommended in table 522-08-03 of BS7671 (IEE
Regulations) and the cable manufacturer‟s recommendations.
B1.18.3
Terminations
Each armoured cable shall be dressed carefully into position and then terminated in a compression type gland
comprising a main body with a tapered cone, an armour clamping ring earth tag and a gland nut. Cables
terminating in exposed outdoor locations shall be additionally fitted with a compression outer sealing ring. The
glands shall be complete with a backnut and correctly fitted gland shroud.
Where necessary or as specified, cable extension boxes shall be fitted to switchgear, to allow adequate space
for the dressing and termination of larger cable conductors.
Stranded copper conductors taken direct into tunnel terminations, shall be made up to ensure that they fill the
bore of the terminal before the terminal screws are tightened.
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Part B: Materials and workmanship
Section B1: Materials
Larger conductors, shall be terminated using soldered or crimped lugs, for bolting on to switchgear terminals.
Solid sector shaped aluminium conductors shall be swaged circular with a suitable compression tool/die and
fitted with a split brass sleeve where they are to be terminated direct into tunnel type terminations.
Where aluminium conductors are to be terminated onto studs, busbars or bolt type terminals then either
compression or solder type terminations shall be used.
In removing the insulation of the cable cores; only sufficient insulation shall be removed to enable the bare core
to enter the terminal or socket; bare cores shall not project beyond a tunnel terminal or socket.
Tee and through joints will only be allowed if specified or called for on the drawings. Where joints are required
they shall be made using a two section plastic shell, mechanical compression type connectors, armour bonds,
clips, seals and a two part encapsulating resin compound. The jointing kits shall be of the type approved by the
manufacturer of the cable.
The instructions provided by the manufacturer of the jointing materials for the preparation, making and
completing the joint shall be closely followed.
Care shall be taken to ensure that the resistance of any joint or connection is kept to a minimum, but particular
attention shall be given to aluminium cored cables to ensure that the resistance of the joint will not increase due
to oxidisation or by electrolysis.
B1.19
Fabricated switchboards
Main and sub-main switchboards which are to be site fabricated, shall comprise factory made and tested
equipment of the same manufacture, generally arranged and of the overall dimensions as specified and as
shown on the drawings. All site fabricated equipment shall be tested and certified by the equipment
manufacturer.
All equipment shall be mounted on steel or angle iron, bolted and welded together to form a framework to
adequately support all components of the switchboard.
The framework shall be securely fixed to the wall as clause A1.26 and where necessary extended down to the
floor to support the downward thrust.
Switches, switch fuses, fused switches, busbar chambers, distribution boards etc., shall be metal clad and
together with HRC fuses, MCCB's, MCB‟s be of the type and ratings as detailed on the drawings and Part C
Particular Specification.
Busbar chambers shall be totally enclosed, and as far as is practical, be the same width as the switchboard
frame. The busbars shall be copper and fitted with two spare clamps on each bar for the connection of future
equipment.
Holes cut in busbar chambers or trunking shall be neatly made and uniform and shall be filed or reamered to
remove ragged, burred or sharp edges. The holes shall be large enough to easily accommodate the number of
cables passing through, and shall be grommetted to prevent abrasion.
The switchboard shall be complete with all necessary copper cable inter-connections. Interconnections
between busbars and switchgear shall be sufficient to carry the maximum current rating of the switchgear being
connected.
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Part B: Materials and workmanship
Section B1: Materials
Interconnecting cables shall be made off onto the busbars either by Patent clamps of the same manufacture as
the busbar, or by sweated or crimped lugs, bolted to the busbar by steel nuts, bolts and locking washers.
Phase connections shall be made in accordance with the diagram of connections shown on the schematic
drawing.
The framework of the panel on completion, before mounting the components, shall be thoroughly brushed and
cleaned, to remove rust, and a primer, colour undercoat, and a finish coat shall be applied.
All fixing bolts shall be mild steel, and shall be provided with washers, anti-vibration spring washers and nuts.
Each component of the panels shall be labelled in accordance with the requirements of Clause No. A2.4. The
busbar chamber shall be provided with a label engraved with 50mm red lettering reading:
DANGER 400 VOLTS
All items of equipment shall be bonded to the framework and to an earth bar in accordance with clause A2.2.
Equipment shall be mounted at a height on the panel such that cables can be properly terminated, and
subsequently withdrawn and replaced without removing the equipment. Unless approval is given by the
Engineer, no operating handle or push button shall be less than 450mm or more than 2000mm above finished
floor level. Padlocks for operating handles shall be provided where called for in Part C Particular Specification.
Provision shall be made for the accommodation of the electrical supply company‟s metering equipment, time
switches and contactors on switchboards at the incoming supply. The Contractor shall liaise with the electrical
supply company to ensure that space is provided in positions on the panel suitable for the metering equipment.
Switchboards on which the electrical supply company‟s equipment is to be accommodated shall be provided
with suitable tails for connection by the electrical supply company. Proposals for the layout, and overall
dimensions of the switchboards fabricated on site shall be submitted to the Engineer and approval received
before construction is started.
B1.20
Cubicle switchboards and panel boards
Cubicle type main and sub-main panel boards, shall be of the manufacture as specified in Part C Particular
specification, and shall be manufactured in accordance with
BS EN60439-1, IEC60439. Cubicle switchboards shall comply with the requirements of Form 4b Type 2 and
panel board shall comply with the requirement of Form 3b Type 2 as a minimum.
Moulded case circuit breakers and HRC fuse switches to be incorporated into the board, shall be of the type and
ratings as indicated in the specification and on the drawings, and shall comply with BS EN60947-2 and BS
EN60947-3 respectively.
The board shall incorporate busbars of hard drawn high conductivity copper, housed in a separate
compartment. All phase busbars including the neutral shall be fully rated throughout the length of the assembly.
A copper HDHC earth busbar shall run the length of the assembly and the main structure together with all
devices shall be bonded by copper tape or cables to the earth busbar. Segregation shall be provided between
devices, and where constructed on a modular basis shall be arranged so that devices can be interchangeable.
The panel shall incorporate all necessary cable wiring ways with cable tray, top and bottom removable gland
plates, and gasketted doors with key locking.
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Part B: Materials and workmanship
Section B1: Materials
The board shall be finished with stove enamel or epoxy powder paint to the required colour. All devices shall be
labelled in accordance with this specification, and warning labels shall be fitted to all covers and doors to comply
with BS7671 (IEE Regulations) and Health and Safety at Work Act.
Phase connections shall be made in accordance with the diagram of connections shown on the schematic
drawing, and shall incorporate spare ways for 25% future extension or as indicated on the drawings. Cubicle
switchboards shall be arranged for floor mounting and panel boards for wall mounting. Both to be securely
bolted in position relative to any ducts or cable trenches that have been provided. Fixings shall be carried out
using expanding bolts in accordance with clause A1.26. Care shall be taken to ensure that cabling access is
arranged for either front or rear, as appropriate to the type of equipment and installation. Suitable access shall
be maintained for future cabling and maintenance.
The metering strategy for outgoing circuits shall be as described in the supplementary specification.
B1.21
Busbar chambers
Busbar chambers shall be constructed of sheet metal and shall contain hard drawn high conductivity copper
busbars mounted on good quality insulators. The busbar chamber shall be of a clean line design with external
protrusions eliminated as far as possible. The unit shall have busbars of the sizes or rating shown on the
drawing. The busbar chambers shall comply with the requirements of the BS 159 and BS60439-1.
Cable interconnections to the bars shall be made with the manufacturers approved mechanical clamp cable
sockets. The cable sockets shall be of the heavy duty brass pattern. All connections shall be secured with
brass bolts, washers, anti vibration spring washers and nuts.
Slots and holes cut in the busbar chamber housing shall be of an adequate size to prevent undue bunching of
the cables. Smooth bore brass bushes for holes or smooth insulating boards for slots shall be installed to
protect cable insulation. All holes and slots shall be free from burrs and rough edges. Loose fit plastic section
beading fitted around holes and slots will not be accepted.
Holes for cable gland connection shall be of the correct size for the gland and free from burrs. Holes to
accommodate single core cables shall be slotted between holes to prevent the presence of Eddie currents.
The inside of busbar chambers shall be thoroughly clean of all rubbish and swarf before energising.
All exposed metalwork is to be efficiently earthed.
Where busbar chambers form part of a main or sub-main switch panel they shall be mounted on a slotted steel
or angle iron frame adequately supported off the wall or floor.
B1.22
Distribution boards
Distribution equipment shall be steel cased enclosing all busbars, terminals, MCB‟s and HRC fuse carriers.
Each board shall be either S.P.N, TP & N and of the size as indicated on the drawings. (25% spare capacity as
a minimum shall be allowed for all distribution boards).
Boards shall be complete with integral isolator, hinged lockable access door to the overload devices, flush or
surface mounting as required. Consumer units may have all insulated cases where specified.
Distribution equipment shall comply with the following British Standards:
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
HRC Fuseboards
MCB Distribution Boards
MCB/HRC Consumer Units
-
BS 5486 Part 11
BS 5486 Part 12
BS 5486 Part 13
Earth and neutral bars shall have a terminal for each circuit way. All neutral and earth connections shall be
made in the same order as the outgoing ways. Numbered marker tags shall be attached to each circuit
conductor (including neutral and CPC) corresponding to the outgoing way number to aid future identification and
maintenance.
Distribution Boards shall be fitted with an MCCB, MCB or a fuse carrier, holder and HRC fuse of the rating and
having the number of poles indicated in the schedule. Blanking pieces manufactured by the maker of the board
shall be fitted to ways not fitted with MCCB‟s or MCB‟s. Where distributing boards are to be surface mounted
on a flush installation, the conduits shall enter appropriately sized flush mounted adaptable boxes, over which
the distribution boards shall be mounted and through which the cables shall be brought. Cable entries and slots
in the rear of the distribution board shall be bushed to prevent abrasion of the cables. A spare conduit shall be
installed from the adaptable box to the ceiling for future use.
Distribution Boards shall be sited in the locations shown on the drawings and erected in the precise position
given on site by the Engineer. Distribution Boards not incorporated on switchboards shall be mounted no higher
than 2000mm measured from finished floor level to the underside of the Board.
Each Single Phase way on the Distribution Board shall be clearly numbered. The numbering of the way on the
Distribution Schedule shall correspond to the allocated number of the phaseway on the Distribution Board.
Every distribution board shall be fitted with an engraved ivorine label denoting its designation.
B1.23
Moulded case circuit breakers
Moulded case circuit breakers shall be manufactured in compliance with BS EN60947-2 with frame sizes and
short circuit capacity ratings in accordance with Part C Particular Specification and the schematic drawings.
Circuit breakers shall have an over centre trip free toggle action operating mechanism, with a quick make, quick
break action and positive hand indication. A heavy duty cross bar shall link across all poles to ensure common
tripping.
The trip unit shall contain thermal and magnetic trip elements on each pole, and assume a centre position when
the circuit breaker is tripped. The handle shall not allow false indication, and shall comply with BS EN60947-3
for contact separation and use as a means of isolation.
Resetting shall be by moving the handle to 'Off' and back to the 'On' position again.
For circuit breaker of frame ratings greater than 400 amps, a push button shall be provided on the front, for
mechanically tripping the circuit breaker.
B1.24
Miniature circuit breakers
Miniature circuit breakers shall be manufactured in accordance with BS EN60898. They shall be of the
thermal/magnetic current limiting type, providing both overcurrent and short circuit protection.
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Part B: Materials and workmanship
Section B1: Materials
Miniature circuit breakers shall be type B unless otherwise stated in the Particular Specification Part C and on
the drawings, with an interrupting capacity of at least 9000 amps at 230/400 volts calibrated at an ambient
temperature of 40°C.
When a short circuit or overload occurs the breaker handle shall move to the 'Off' position, automatically reset,
but requiring the handle to be moved to the 'On' position before the circuit can be restored. The handle shall be
of the trip free type so that if the device is closed onto a fault, tripping will occur irrespective of the position in
which the handle is held.
There shall be positive indication that the contacts have separated for the purposes of isolation, as paragraph
537.2.2.6 of BS7671 (IEE wiring regulations) and BSEN60947-3. A semi conductor device shall not be used as
an isolating device.
Where additional protection is required against 'Direct' and 'Indirect Contact', residual current devices which
comply with BSEN61008-1 shall be provided. These shall take the form of combined over current/residual
current protection devices (RCBO) with a rated residual tripping current as the Particular Specification Part C
and as indicated on the drawings.
Where necessary, suitably rated back-up fuses or moulded case circuit breakers shall be installed to protect
miniature circuit breakers where the prospective fault level is higher than the maximum breaking capacity of the
breaker.
B1.25
Fuses
All fuses shall comply with the relevant British Standard Specifications and shall be supplied to suit the ratings
and class of circuit protected.
Only fully enclosed cartridge type fuses shall be used not rewireable type. Where specified for use in
distribution boards and switchfuses, high rupturing capacity (HRC) fuses to BSEN60269-1 and BSEN60269-2,
ASTA certified shall be installed.
Circuits requiring motor protection, shall be fitted with high rupturing capacity motor type fuses, which are
specifically designed to cope with the associated high starting currents.
Fuse bases and carriers shall be fully shrouded to prevent accidental contact with live parts and be fully
distinguishable by approved colourings.
Fuses shall have their rating inscribed on the fuse carrier or label, and be mounted in their carrier so that the
current rating is clearly visible. All fuses shall be distinguished by appropriate colourings.
Fuses for incorporation into 13A plug tops, connection units etc, shall comply with the requirements of BS 1362.
B1.26
Fuse switches
Fuse switches shall comply with BSEN60947-3, quick make/break switch mechanisms of the spring loaded
type, such that the speed of operation cannot be controlled by the operator.
Clear indication of the status of the switch, shall be provided by an „On/Off‟ flag indicator positively linked to the
fuse carriage.
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Part B: Materials and workmanship
Section B1: Materials
It shall not be possible to open the door of the fuse-switch when in the „On‟ position, unless the interlock is
intentionally defeated. Doors shall be gasketted to prevent the ingress of dust.
All live parts and terminals shall be fully shrouded to prevent accidental contact. Access to fuse links shall not
be possible unless they are de-energised.
Contacts shall be silver plated and the fuse carriage removable for renewal or maintenance. Where the fuseswitch is to be used as an isolator fuses shall be removed and replaced with solid copper links.
Pad locking facilities shall be provided for locking the handle in the „off‟ position, where called for in the
Supplementary Specification or the drawings.
B1.27
Contactors
All contactors shall be made in accordance with BSEN60947-4-1 for uninterrupted rating, mechanical duty Class
I and making and breaking capacity category A4 or D4 for AC and DC circuits respectively, with fused coil
circuits. Unless otherwise specified, contactors shall have integral rectifiers fitted to the coil circuit to operate
the coil on rectified alternating current. All coil circuits shall be sub-fused and shall be supplied with the coil
voltage as specified.
All contactors shall be supplied for the current rating specified. The Contractor should note that for inductive
loads appropriate rated contactors shall be used.
Where applicable, contactors shall be fitted with arc shield and magnetic blow outs.
Contacts shall be easily renewable and of the self-cleaning type. The design shall be such as to prevent
welding-in.
B1.28
Motor starters
Direct on line motor starters shall incorporate an air break type magnetically operated contactor to connect the
motor to the mains supply. Starters shall be provided with thermally operated adjustable trips in each phase.
Starters to be fitted on machines shall be provided with an on/off push button, under voltage trips, and where
specified indicator lights.
Starters to be included in heating and ventilation systems shall have on/off push buttons or arranged for pilot
wire control as detailed on the drawings. Starters for pilot wire control shall be without no volt trip and fitted with
manual reset over-load.
Star-delta starters shall be of the air break automatic type incorporating magnetically operated contactors to
change motor connection from star to delta by means of a time delay mechanism, adjustable between 3 and 20
seconds. Thermally operated adjustable trips shall be installed in each phase.
All starters shall be supplied in sheet metal or other type enclosures with IP ratings and cable entries of the type
as specified.
All thermal overloads shall be of a rating to match the motor current and shall be adjusted to trip on 130% of full
load motor current.
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Part B: Materials and workmanship
Section B1: Materials
All starter for loads exceeding 5KW shall incorporate soft starting to reduce large starting currents.
B1.29
Control panels
Control panels for items of mechanical equipment shall be constructed in accordance with BSEN60439-1.
Control panels for installation within the areas having corrosive atmosphere shall be of a finish guaranteed
impervious to the corrosive atmosphere.
The necessary items of isolating, starting and control gear shall be mounted within the panels. The panel shall
be arranged for front opening.
The panel shall incorporate main isolator interlocked with the front opening door. The isolator shall be of the
type to prevent operation when the door is in the open position.
No item of control gear except stop/start buttons, selector or isolating switches and indicator lamps shall be
mounted directly on the opening cover. Starter and contactor mechanisms shall be mounted within the casing.
All timers, speed controllers, etc., which require access for adjustment by unskilled personnel, shall either
extend through the opening cover or have over-ride facilities mounted on the front cover.
Internal control circuit wiring shall be grouped together in a wiring harness, with all conductors labelled and
coded to match the manufacturers wiring diagram.
All circuits shall be protected against overload and short circuit by means of fuses or circuit breakers mounted
within the panel.
A fixed din type rail shall be provided for the termination of all outgoing circuit wiring. The terminal rail shall be
located so as to ensure easy access and ample wiring space.
All controls and indicator lamps on the front cover shall be clearly labelled as to their function with screw fixed
engraved ivorine labels.
The panel shall be constructed in sheet steel or other type of enclosure, with IP ratings and cable entries as
specified. Control panels shall be tested and certified by the equipment manufacturer.
B1.30
Lighting switches
Local lighting switches for the control of lighting circuits, shall comply with BS60669-1. Switches shall be one
way, intermediate or two way as required, either single units or ganged together on a common plate as
indicated on the drawings.
Switches for concealed installations, shall be mounted on flush steel boxes with adjustable accessory fixing or
fast fix boxes for installation within plasterboard/partition walls with flush overlapping cover plates.
Switches for surface locations shall either be all metalclad pattern/insulated pattern, mounted on surface steel
boxes or surface UPVC boxes, to suit the accessory finish and particular cable installation. Location of lighting
switches shall be in accordance with L2 of the building regulations.
Where required to be mounted externally or in moist atmospheres, they shall be weatherproof type, insulated
impact resistant type with neoprene seals to aluminium, to a minimum of IP54 rating.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Plate switches shall comprise 10A white moulded insulated pattern for flush mounting.
Grid switches shall comprise insulated 'rocker' type switches, 20A pattern mounted in steel adjustable grids,
with cover plates of the type and finish as specified. Grids shall have an earth terminal for connection of a flying
earth lead to the earth terminal within the accessory box.
For multi-gang units where different switches are connected to two or more different phases, each switch shall
be insulated from all other switches be means of an approved insulating material and dividing phase barriers.
A sheet of insulating materials shall also be installed beneath the switch plate coloured red, fixed by means of a
separate set of screws and labelled:
DANGER 400V
Switches shall be of the type that do not need to be derated when used with fluorescent or inductive loads.
B1.31
Ceiling lighting switches
Ceiling switches shall be of the surface pattern suitable for fixing directly on a standard 50 mm B.E.S.A. conduit
box, or surface mounting pattress as determined by the installation. Where such switches are fixed to flush
boxes, suitable plastic break rings shall be interposed between switch and supporting box and the ceiling. The
switches shall be supplied complete with pull cords, the length of which shall be adjusted on site to suit the
siting of the switch. The ceiling switch shall incorporate a visible indicator to identify that the switch is in „on‟
position.
Ceiling switches shall comply with BSEN60669-1.
Switches shall be one way, two way as indicated on the drawings, either 10A, 16A, 32A or 45A depending on
the load.
B1.32
Ampere socket outlets
All 13A sockets outlets shall be switched unless otherwise specified and comply with BS 1363-2. Socket outlets
shall be either 1 gang or 2 gang as indicated on the drawings.
Socket outlets for concealed installations shall be mounted on flush steel boxes with adjustable accessory fixing
lugs and flush overlapping cover plates.
Socket outlets for surface locations shall either be all metalclad pattern insulated pattern, mounted on surface
steel boxes or surface UPVC boxes, to suit the accessory finish and particular cable installation.
The earthing terminal of every socket shall be connected to the earth terminal of the socket outlet box using an
earth fly lead having a minimum cross sectional area of 2.5mm².
Socket outlets on circuits containing electronic equipment with an earth leakage exceeding 10mA shall have
dual earth terminals to comply with BS7671 regulation 543.7.
B1.33
Fused connection units
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Fused connection units shall be of 13 amp rating, combining a D.P. switch, single pole fuse in a captive holder,
neon indicator light with flex outlet where called for in the Particular Specification Part C.
Connection unit shall comply with BS 5733, BS1362-4 and be fitted with ASTA certified fuses to BS1362.
The finish of fused connection units, shall match that of any other accessories specified for the same area.
Generally connection units shall be flush pattern with overlapping plates mounted on steel accessory boxes.
Where surface fixed, they shall be of all metalclad pattern or insulated pattern on steel or UPVC boxes as called
for in the specification.
The earthing terminal of the fused connection unit, shall be connected to the earth terminal of the accessory
box, with a 2.5mm² green/yellow bonding fly lead.
Connection units shall be fitted with fuses appropriate to the appliance being supplied and the currents rating of
the interconnecting flexible cord.
B1.34
Cooker control unit
Cooker control units shall comprise a 45A DP switch with pilot light, and shall be mounted in an all insulated or
metal front plate. The front plate shall be engraved:
COOKER
The cooker control unit shall comply with BS 4177.
For flush installations the unit shall be mounted in a steel accessory box set flush in the wall. For surface
installations the unit shall be mounted in a surface all insulated box or steel box with edges of the box flush with
the unit front plate and of a matching finish.
Reference shall be made to the Schedule of Nominated Manufacturers and or the specification to determine if
all insulated or metal units shall be used in a particular installation.
For all cooker control units, supply and install a connector box positioned adjacent to the cooker terminals at
450 mm above FFL. Wiring between the control unit and connector box shall be carried out with 10mm² PVC
cable enclosed in conduit.
The connector box to BS 5733 shall comprise a flush mounted steel accessory box containing a 3 way 45A
terminal block suitably shrouded. The box to be fitted with a cable grip and overlapping all insulated front plate
with provision for cable exit to cooker.
B1.35
Shaving outlets
Where shaving outlets are to be installed in bathrooms they shall comply with BSEN61558-2-1 and incorporate
a high vacuum varnish impregnated double wound transformer to provide an earth free supply at mains
frequency.
The outlets shall be fitted with a self resetting thermal trip fitted in the primary circuit. The outlet shall be
provided with a shuttered socket outlet suitable to accommodate shaver plugs to British, American, Continental
and Australian Standards.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Where shaving outlets are to be installed in areas other than bathrooms, they shall comply with the BS 4573
and contain a socket outlet of the pattern detailed above, and shall be fitted with a thermal cutout to limit the
output to 200 mA and be provided with fuse protection.
The outlets shall be single voltage 240 v output.
Where indicated on the drawings and/or Schedule of Nominated Manufacturers, the shaving outlets shall be
incorporated in lighting fittings.
All shaving outlets shall be of the all insulated pattern finished white, front plate engraved:
SHAVER ONLY
Where installed as part of a flush installation, they shall be mounted in a steel accessory box set flush in the
wall.
B1.36
Accessory boxes
Boxes installed for the mounting of accessories shall be surface or flush steel or UPVC as required. Flush
boxes shall have adjustable accessory fixing lugs.
Boxes recessed in walls, ceilings and floors shall be installed to ensure that the face of the box is flush with the
wall/ceiling/floor finish so that the inside of the accessory face plate abutts with the face of the box. If necessary
box extensions shall be used.
Care shall be taken to ensure that boxes are installed so that the vertical sides of the boxes are perpendicular.
Unused entries in flush boxes shall be blanked off before installation to prevent the ingress of plaster and
building material.
Blanked off entries will not be allowed in surface boxes.
Surface metal boxes shall not have knockouts.
Each box shall have a minimum of two round head screw fixings.
Boxes shall be of a sufficient depth to ensure that cables are not cramped when the accessory is fitted in
position.
All accessory boxes shall be fitted with brass earth terminals.
Accessory plates shall not be installed until decorations in any location are complete.
B1.37
Ceiling accessories
Pendant lighting points shall comprise, either a two terminal and earth, or two terminal, loop-in terminal and
earth ceiling rose. Circular heat resisting PVC flexible cord and heat resistant lampholder.
Ceiling roses shall comply to BS 67 and lampholders to BSEN61184 T2 rated with an efficient cord grip.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Plug-in ceiling roses shall comprise a ceiling socket base with two terminals, loop-in terminal and earth. A
ceiling plug fitted with three terminals, cord grip and cover. The maximum weight that can be supported by
these roses is 5kg. However loads imposed on flexible cords must not exceed those stated in
Luminaries that are in excess of 5kg, should be supported independently of the flexible cord by means of ceiling
hook and straining wire or as recommended by the fitting manufacturer.
Batten holders should be of the heat resistant type, two terminal with loop-in and earth, complete with Home
Office Shield all in compliance with BSEN61184 T2 rated.
All ceiling accessories and flexible cords shall be finished white, unless otherwise specified.
B1.38
Lamps
The Contractor shall ensure that lamps and tubes are supplied to all luminaries as detailed on the drawings and
the Particular Specification Part C.
Care shall be taken to ensure that lamps and tubes are compatible with the luminaire into which they are to be
fitted, and do not exceed the maximum recommended wattage.
Fluorescent tubular and compact type lamps shall comply with BS 1853-2. Tubular lamps shall be 16mm
diameter T5 energy saving type unless otherwise specified. If colour is not indicated in the drawings or
specification they shall be white with a colour temperature of 4000k.
High pressure mercury vapour lamps shall comply
Low pressure sodium vapour lamps shall comply
High pressure sodium vapour lamps shall comply
with BS EN62035
with BS EN62035
with BS EN62035
Low voltage tungsten halogen lamps with internal reflector, shall be either of the sealed type with front glass or if
open fronted be housed in luminaries with a safety front glass.
General purpose tungsten filament lamps GLS shall have coiled coil filaments and comply with BS EN60064.
The number of different lamp tyres shall be kept to a minimum to ease future maintenance.
B1.39
Electromagnetic compatibility
Segregation Details for Power and Signal Cables
Without divider or
non-metallic divider
(1)
Aluminium
divider
Steel divider
Unscreened power cable and IT cable
200m
100mm
50mm
Unscreened power cable and screened IT cable
50mm
20mm
5mm
Screened power cable and unscreened IT cable
30mm
10mm
2mm
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B1: Materials
Screened power cable and screened IT cable (2)
0
0
0
Note 1: It is assumed that in case of a metallic divider, the design of the CMS will achieve a screening
attenuation related to the material used for the divider.
Note 2:
The screened IT cables shall comply with EN 50288 series.
END OF SECTION B1
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
B2 Installations
B2.1
Lighting circuits
The Contractor shall supply and install all wiring from distribution boards to lighting points and switches all as
indicated on the drawings. Methods of installation and types of wiring to be used shall be as detailed in the
Particular Specification Part C.
Wiring is to be carried out as a loop in system. Circuits are to be looped at ceiling points and switch positions
and except where specified, no joint will be permitted in the run of any conductor. The circuits will be run and
arranged as shown on the drawings.
All cables shall have a minimum cross sectional area of 1.5mm² 600 volt grade, with not more than 3 conductors
being bunched at each terminal.
Wiring shall terminate at lighting points in a manner as detailed in the Supplementary Specification and set out
on the drawings.
At every lighting point, an earthing terminal shall be provided. A 1.5mm² green/yellow earth lead shall be
installed from the ceiling point to any luminaire which contains extraneous conductive parts.
As a general rule not more than 10 luminaires shall be connected to one lighting circuit.
The use of automatic lighting controls shall be used to aid compliance with Part L2 of the building regulation.
This shall consist of presence detection to toilet, corridor, circulation areas incorporating adjustable time and
lighting levels settings in accordance with Part C of the Particular Specification. Where applicable the use of
absence detection (incorporating daylight linking with adjustable time lighting level setting where there is
sufficient natural daylight) operated by a monitory switch in accordance with Part C of the specification shall be
utilised. Local means of isolation shall be afforded to the automatic lights controls for ease of maintenance.
This should consist of a H/L key switch located in the area that the automatic light controls are installed. The
isolating key switch shall be suitably labelled to identify its use.
B2.2
Erection of luminaires
B2.2.1
General
The Contractor shall supply and install all luminaires and lamps as detailed in the Particular Specification Part C
and indicated on the drawings, provide all necessary flexible cords, break joint rings, connectors, fixings screws
and additional material to leave the luminaires in full working order. Luminaire, shall be installed in accordance
with BS7671 regulation 559.
Unless otherwise specified within the Particular Specification Part C, all luminaires shall be high frequency.
The Contractor shall obtain the approval of the Engineer before ordering the luminaires.
Connectors for use in terminating hard wiring and final connections to luminaires, shall be of the fixed base type,
with brass tunnel type clamp and brass threaded clamp screws. The brass terminal shall either be enclosed in
porcelain or high grade self extinguishing plastic suitable for operating temperatures of 120ºC. The moulding
shall surround all conductive parts in accordance with BS EN61032.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
B.2.2.2
Fixing of luminaires
Luminaires shall be fixed or suspended at the heights given in the Particular Specification Part C or as indicated
on the drawings. The precise position shall be agreed on site, to suit the building symmetry or ceiling layout.
Luminaires, lighting track and tubular type systems shall be securely fixed to support the total weight and the
strains imposed when maintenance, fitting of new lamps, adjustments to track luminaires and other such
operations are carried out, by both skilled and unskilled personal.
Linear fluorescent luminaires shall be supported and fixed in a minimum of 2 places located at either end, and
modular fluorescent luminaires in a minimum of 4 places located to the corners.
Tubular type lighting systems shall be fixed and supported using the manufacturers own patent connectors,
brackets adjustable wire and pendant rod type suspension in accordance with the manufacturers
recommendations.
Luminaires and lighting systems suspended from the floor or roof slab soffit shall be suspended by the luminaire
manufacturer‟s suspension kit, after levelling and alignment with the ceiling, shall be cut to length and not
project into the fitting more than is necessary.
Support for luminaries shall be derived from the structural elements of the building using approved fixing
methods and in no circumstances shall the weight of luminaries be imposed directly on ceilings (this does not
apply to surface or fully recessed luminaries where manufacturing purpose made fixing kit and installation
method is used).
Where semi or fully recessed luminaries are cut into ceiling tiles as suitable pattress shall be installed behind
the tile to support the luminaire. The pattress shall be the same size as the ceiling tile.
Remote battery packs and control gear shall be securely fixed within ceiling voids using manufacturers fixing
kits. Under no circumstances are remote control gear to be left loose on ceiling tiles.
All luminaries shall be left in a clean dust free condition and anti-static cleaner shall be used where appropriate
on plastic materials.
The Contractor shall be responsible for all breakages prior to handover and shall provide and install all
replacements at his own expense. The permanent lighting installation shall only be used as working lighting
with written permission of the Engineer, and if such permission is given, it shall be on the understanding that all
lamps are replaced with new prior to handover.
Generally luminaries shall be low energy linear or compact fluorescent type except where specifically detailed
otherwise. No tungsten light sources shall be employed (with the exception of LV diachronic luminaries used for
display areas only). All luminaries shall comply with BS4533 103.2 BSEN 60598 2-7.
Care shall be taken to ensure that ceiling panels and grids are not damaged or soiled when luminaires or
lighting systems are erected.
Provision shall be made for adjusting the height of luminaires and lighting systems suspended from the soffit of
a floor, roof or canopy and mounted in or on a suspended ceiling.
The contractor shall co-ordinate his work with the Main Contractor and/or other trades, to ensure suitable
access in the ceiling space and to the ceiling to erect the luminaries.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
B.2.2.3
Final connections to luminaires
Surface mounted fluorescent lamp luminaires mounted direct to conduit boxes, shall have the circuit wiring
taken direct into the terminal block mounted within the luminaire, so routing conductors to avoid passing
luminaire control gear.
Surface mounted tungsten lamp luminaires mounted direct to conduit boxes, shall have the circuit wiring
terminated into a fixed base connector within the circuit box. Final connection to the luminaire shall be by
means of silicon rubber glass braided flexible cable.
Low voltage luminaires shall be connected and terminated in accordance with the manufacturers
recommendations. Circuit wiring shall be terminated into a luminaire type plug and socket arrangement, with a
flexible heat resisting cord connection to the transformer. The plug and socket shall be arranged to be
accessible when the luminaire is removed, so that the transformer can be unplugged for future maintenance or
repair. Final connection between terminal block and transformer shall be carried out using the manufacturer
supplied cable tails or wiring harness when group supplied from a single transformer.
Luminaires mounted on or recessed into suspended type ceiling systems, shall have the circuit wiring
terminated adjacent to the luminaries in a soffit, slab or roof mounted conduit box with a plug-in ceiling rose.
Final connection shall be by means of flexible cord.
Luminaires recessed into ceilings that do not have removable panels adjacent shall have the plug-in ceiling rose
so sited, and the flexible cord of sufficient length to be accessible from the recess for the luminaire when it is
taken down.
Final connections to lighting track recessed in, or mounted on, suspended ceilings that are accessible by the
removal of an adjacent ceiling panel shall be connected by flexible cable from a fixed base connector in a
conduit box, fixed to the soffit, slab on roof.
Final connections to lighting track mounted surface on suspended ceilings that are inaccessible, shall be
connected by flexible cable from a fixed base connector in a flush ceiling box directly above the track connector.
Surface wiring connections to lighting track shall be by conduit or glanded cable entry into the connection box of
the track.
Suspended type lighting systems shall have the circuit wiring terminated by one of the methods previously
described, but final connection from ceiling to the connection point within the system, shall comprise either a
wired pendant rod or spiral extending flexible cable.
Wall mounted luminaires shall either be mounted on or over conduit boxes with fixed base connectors, or where
specified shall be supplied complete with 3 pin lighting plug, allowing them to be fixed direct onto patent type
lighting sockets.
Through wiring of luminaire shall only be permitted if the luminaire is designed for through wiring. Cables for
through wiring shall be selected in accordance with the intended temperature of the luminiare.
The general lighting installation shall not be used for construction lighting without the written permission of the
Engineer. If permission is granted the contractor shall allow to re-lamp all luminaries used for construction with
new lamps at their cost. If general lighting is used for construction work lighting the emergency batteries (where
fitted) should be disconnected if the lighting circuits are to be turned off for periods longer than one hour.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
B2.3
Emergency lighting
B2.3.1
General
The Contractor shall allow to supply and install emergency lighting system complete with all luminaires, lamps
and batteries in accordance with the drawings and Particular Specification Part C.
Self test emergency luminaires shall be provided with a means of logging test information and alerting any
fault/lamp failure at a central point. All self test luminaries shall be connected to the central monitoring unit by
means of a bus/communication cable in accordance with the emergency luminiare manufacturers requirement.
Care shall be taken to avoid causing nuisance/disruption to building occupants during the luminairs self test
operation. Stand alone self test emergency luminaires shall not be used.
Emergency lighting systems shall be designed and installed in accordance with Code of Practice BS 5266 Pt 1
and BSEN 1838:1999, luminaires manufactured in accordance with BS EN60598-1 and ICEL 1001 certified.
Illuminated exit signs shall comply with BS 5499-1, -2, -3, -4 and ICEL 1004. Guide to the use of Emergency
Lighting Modification Units shall be consulted where it is intended to convert new or existing mains voltage
luminaires to emergency use.
B.2.3.2.
Self-contained luminaires
Luminaires shall comprise an automatic charging system coupled to re-chargeable sealed cells of the nicked
cadmium type. All cells used shall be of the high temperature type, suitable for continuous use in accordance
with BSEN 60589-2-22. Following a complete discharge, the charging circuit shall be capable of restoring the
batteries to a fully charged state in 24 hours. Charging circuits shall incorporate deep discharge protection.
Self contained luminaires, shall be provided with a permanent mains connection from the same circuit as the
general lighting to that area. The mains supply and continuity of the battery charging circuit, shall be monitored
by a light emitting diode, indicating that conditions are healthy. Upon a mains failure the luminaires shall
automatically illuminate, for a period of not less than 3 hours.
Wiring to luminaires shall be the same as that specified for the general lighting circuits. Luminaires shall be
non-maintained. sustained or maintained as indicated on the drawings.
Remote battery packs and control gear shall be securely fixed within ceiling voids using manufacturers fixing
kits under no circumstances are remote control gear to be left loose within ceiling voids.
Key operated DP switches connected to the live and neutral supplies to emergency luminaires, shall be
provided by the Contractor for testing purposes. These switches shall be located on the nearest wall preferably
ganged with a „normal‟ lighting switch, or as indicated on the drawings. Front plates of switches shall be
engraved adjacent to the appropriate switch(es) EL Test.
B2.3.4
Central battery systems
This type of system shall comprise a set of batteries, either floor or wall mounting depending on size and
capacity, supplying slave luminaires in the positions as indicated on the drawings.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
The central battery unit shall comprise a sheet steel enclosure, with shelves that are acid resistant for vented
type cells, fully automatic floating battery charger, deep discharge and low voltage disconnection circuits for
battery protection, depending on which types are specified. Changeover contactor, mains on/off switch, mains
healthy lamp, maintained on/off switch, maintained indicating lamps and other instrumentation/alarm circuits as
specified in the Particular Specification Part C.
The battery system shall be complete with maintenance/operational notes, hydrometer if appropriate and all
associated tools and equipment.
On larger systems in addition to normal mains failure operation, sub-circuit monitoring shall be provided for
individual circuit or fuse failure. This shall be carried out either by means of relays sited in the Central Battery
Cubicle, or in control boxes adjacent to the distribution boards containing the lighting circuits it is desired to
monitor. In this way any number of circuits can be individually monitored and a circuit failure will energise the
emergency lighting system.
Wiring to slave luminaires shall be segregated from all other wiring and circuits in accordance with BS. 5839
and BS. 5266. Under BS7671 (IEE Regulations) emergency lighting cables are classed as Band 1 and
Regulations 528-01 shall apply.
Circuit wiring to luminaires shall be the same as that specified for the general lighting circuits, but in the case of
PVC cables, should be given additional protection in the form of PVC or steel conduits.
B2.4
External lighting
The Contractor shall supply and install external lighting columns, bollards, luminaires and lamps as shown on
the drawings and scheduled in the Particular Specification.
All builders work and earthing shall be in accordance with Clauses A1.24, A2.2 and in the Particular
Specification Part C.
External lighting columns shall be controlled from the position and in the manner indicated on the drawings and
included in the Particular Specification. The Contractor shall supply and install all wiring, the type and size as
detailed on the drawing, from the distribution board to the lighting standards as indicated on the drawings. The
cables shall be installed in accordance with this specification. The Contractor shall supply and install a plastic
warning tape throughout the length of the underground cable.
In each lighting standard and bollard, supply and install a 15A SP & N cut out suitably fused. The cut out shall
be provided with a junction box arrangement for looping in the underground cable of the type specified.
Wiring between the cut out and fittings shall be carried out with minimum 1.5mm² 6242HB cable.
External lighting fittings mounted on the building shall be connected to the external lighting circuits or switched
locally as indicated on the drawings. Luminaires mounted on conduit boxes shall have a gasket provided
between mounting plate and box to achieve IP55 minimum.
B2.5
General purpose ring circuits
The Contractor shall supply and install all wiring, the method and type to be as indicated in the supplementary
specification, and on the drawings, from the distribution boards to the BS-1363-2 13A switched socket outlets.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
Unless otherwise shown on the drawings all 13A accessories shall be wired and connected as ring circuit
systems with the exception of Science room island units which shall be wired as radial circuits. The circuits
shall comply with the requirements of BS7671 (IEE Wiring Regulations) Appendix 15.
Radial spur circuits shall be taken from a conveniently placed socket outlet or switched fused connection unit
which is connected directly to the ring circuit. Joint boxes shall not be used and not more than 3 conductors
bunched into any one terminal. Only one twin socket outlet shall be taken from the ring circuit as an unfused
spur. Where switched fused connection units are connected to a ring circuit they shall be labelled to identify
what they serve.
Fixed equipment which is to be fed from ring circuits, shall be controlled by a fused connection unit, which shall
be fitted with a fuse appropriate to the current rating of the appliance and flexible cord. Fused connection units,
shall have their front plates engraved as to the item of equipment controlled.
Socket outlets which are connected to different phases in the same room shall be identified accordingly, either
by means of phase discs or labels fitted to the socket, or by engraving the front plate.
The installation shall be complete with all fuses fitted appropriate to equipment being fed, and plug tops shall be
of the type as specified in clause B1.32.
Circuits for socket outlets installed within public areas and school teaching areas shall incorporate 30mA RCD
protection with the exception of science rooms, which shall incorporate 10mA RCD protection to high risk areas
such as installed on island unit close to sinks. Circuits for sensitive equipment, i.e. computer cabinets,
telephones, computers in staff areas, fridge/freezers and fitness equipment that cause a hazard if suddenly
switched off should not be RCD protected. Fridge/freezers, IT cabinets and telephone equipment should be
installed on separate radial circuits. No more than six twin socket (four within science rooms) outlets should be
allowed for circuits incorporating RCD‟s serving computers and other electronic equipment with high earth
leakage. Within educational properties, local means of isolating socket outlet circuits for IT rooms, music rooms
and science rooms shall be allowed via contactors within extension modules to local distribution boards, with the
key control switch located at the teacher‟s work station or position indicated in the Particular Specification and
drawings. Circuits serving equipment with an earth leakage expected to exceed 10mA shall comply with
regulation 543.7 of BS7671 (IEE Wiring Regulations).
Socket outlets serving areas containing fixed bath, shower, sauna or swimming pools shall comply fully with
regulations 701, 702 and 703 of BS 7671 (IEE Wiring Regulations).
Socket outlets shall not be installed within 300mm of a sink unless the socket outlet is splash proof to a
minimum of IP55.
Residual current devices shall conform to BS EN61008-1 and also be sensitive to pulsating DC fault currents.
B2.5.1
CDT workshops/technology and science rooms
All sockets for pupil use and equipment power circuits within workshops/technology rooms shall be supplied via
a contractor controlled circuit. This can be achieved by using a separate contractor controlled distribution board
or a separate enclose for individual circuit contractors.
The teaching station 13A socket outlets and other specific items of equipment such as, computers and water
heaters, are not to be contractor controlled.
RCD‟s rated at 30ma are to be installed to all socket outlets circuits with 13a or other sockets fitted, except
white boards.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
An emergency shut down system shall be installed within each classroom to isolate and control the contractor
controlled circuits. A key reset is to be installed at the teaching station or in a secure area under staff control.
This can be incorporated into a Latching mushroom head emergency stop button (coloured red).
The general classroom area and associated equipment work rooms, shall have a minimum of one Latching
mushroom head emergency stop buttons, (coloured red), on each wall. This will be in addition to the
emergency stop buttons mounted on the equipment.
The supply for the contractor/s shall be derived from an un-controlled source connected directly to local
classroom distribution board.
All equipment isolating switches shall incorporate a padlocking off facility where possible and a padlock and key
provided.
In addition all power circuits shall comply with BS 4163:2000 (and subsequent amendments).
Where a gas service is utilised within the classroom this is to be controlled b y a solenoid interfaced to the Fire
alarm via a “Fire Watch Meden panel or similar. The gas valve is to close upon a fire alarm activation. Where a
Fire Watch/Meden panel or similar are installed, these units can be used to isolate both electric and gas
services.
B2.5.2
Science Classrooms
All sockets for pupil use and equipment power circuits within the science classroom shall be supplied via a
contractor controlled circuits. This can be achieved by using a separate contractor controlled distribution board
or a separate enclosure for individual circuit contractors.
The teaching station 13A socket outlets and other specific items of equipment such as, white boards, cleaners
sockets and water heaters, are not to be contractor controlled.
RCD‟s rated at 30ma are to be installed to all socket outlet circuits, except white boards. Sockets within one
metre of a sink or drainer are to be protected by 10ma RCD‟s.
Socket outlets are Not to be installed within 300mm of a sink unless they are fully protected against splashing or
are IP65 minimum.
All rise and fall equipment is to be connected using flexible conduit. Local means of isolation shall be provided
for rise and fall equipment.
A shut down system shall be installed within each classroom to isolate and control the contractor controlled
circuits, also the Gas and Water services. (Excluding water supply to the Water heater). A “Fire Watch”
/MEDEM panel or similar as detailed within the mechanical specific specification, is to be used.
The supply for the contractor/s shall be derived from an un-controlled source connected directly to local
classroom distribution board.
The “Fire Watch/MEDEM” panel or similar is to shut down the services and contractor controlled power circuits
upon a fire alarm activation. Where a “Fire Watch/ MEDEM” panel for similar are installed, these units can be
used to isolate both electric and gas services.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
Computer circuits are to be controlled separately as detailed in the section for “Circuits Serving Computers and
other IT Equipment”.
B2.5.3
Food technology classrooms
All sockets for pupil use and equipment power circuits such as Gas Cooker Ignition and Electric Cookers within
he Food Technology classroom shall be supplied via a contractor controlled circuit. This can be achieved by
using a separate contractor controlled distribution board or a separate enclose for individual circuit contractors.
Circuits which are not contractor controlled are:Power to Fridges, Washing Machine, Tumble Dryer, Dishwasher, water heaters, teaching station power, white
board supplies and the power in the Dado trunking adjacent to the white board.
RCD‟s rated 30ma are to be installed to all socket outlet circuits, except white boards. Sockets within one metre
of a sink or drainer are to be protected by 10ma RCD‟s. Socket outlets are NOT to be installed within 300mm of
a sink.
A shut down system shall be installed within each classroom to isolate and control the contractor circuits, and
the Gas service. A “Fire Watch” panel or similar as detailed within the mechanical specific specification is to be
used.
The supply for the “Fire Watch/MEDEM panel, white board, etc; and contractors shall be derived from an uncontrolled circuit from the local classroom distribution board.
The “Fire Watch/MEDEM” panel or similar is to shut down the services and contractor controlled power circuits
upon a fire alarm activation.
Computer circuits are to be controlled separately as detailed in the section for “Circuits Serving Computers and
other IT Equipment”. These are generally to be controlled by a key switch positioned by the white board via
contractors.
Classroom socket outlets and power accessories are to be installed to bench mounted accessory modules.
The accessory modules and low level concealed sockets and appliance outlets are to be connected to a
perimeter galvanised steel trunking by flexible metal conduit clipped with saddles. These are to be fitted with
termination glands brushed into the trunking accessory boxes and modules. The size of the flexible conduit is to
be minimum 20mm for 13Aower outlets and 25mm for cookers.
Where 13A sockets are to be fitted to the furthest table (Island), past the cookers, 20mm steel conduit is to be
installed form the perimeter trunking. This is to run along the floor between the cookers and rise up to serve the
outlet. The conduit is to terminate in a conduit box on the end panel of the bench to allow the final connection to
the socket module to be in flexible conduit.
All rise and fall equipment is to be connected using flexible conduit. Local means of isolation shall be provided
for rise and fall equipment.
B2.6
Kilns
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
Kiln circuits shall be fed from the main electrical distribution equipment or sub-distribution equipment (if there is
sufficient capacity) of the building and not from local distribution boards. Each kiln shall be connected to a
separate circuit. Where two kilns are installed within a kiln room, a changeover switch shall be installed to
prevent both kilns being energised at the same time. Each kiln shall have its own means of local isolation.
A kiln warning lamp (twin lamp with red lens or lamps) engraved kiln on should be installed outside above the
kiln room door to illuminate when the kiln is on (one for each kiln). An extract fan controlled by a reverse acting
thermostat should be allowed set at 25-30°C.
Final connection of the kiln shall be in accordance with the manufacturer‟s requirements.
B2.7
Fixed equipment
Except where expressly excluded by the Particular Specification Part C or the drawing, the Contractor shall wire
and connect all machines and auxiliary equipment, leaving the installation complete in every detail and in full
working order. Unless otherwise specified all motors, starters and auxiliary equipment for each machine will be
supplied and fixed under a separate contract. Isolators shall be provided as part of the electrical contract.
Each fixed machine or item of equipment, shall be controlled by an isolator, fitted with a label engraved to
indicate the equipment controlled. The isolator shall be mounted close to the machine or equipment in a
prominent position and incorporate the facility to be padlocked in the off position with the padlock and keys also
provide.
Isolators shall be air break type switches, in sheet steel or high impact polycarbonate enclosure depending on
location. Lids shall be gasketed and switches either DP or TP & N as required.
The minimum size of isolator and cable for final connection of motor circuits shall not be less than the following:20 ampere rated isolator
5.5 kW motor three phase
32 ampere rated isolator
11kw motor three phase
63 ampere rated isolator
22kw motor three phase
100 ampere rated isolator
30kw motor three phase
2 kW motor single phase
1.5 1.5mm²
2.5mm²
cable for motors under 1 kW
cable for motors up to 4 kW
4.0mm²
cable for motors up to 6 kW
6.0mm²
cable for motors up to 8 kW
10.00mm²
cable for motors up to 10 kW
3.5kw motor single phase
7.5kw motor single phase
10kw motor single phase
Final connections between the isolator and equipment shall be enclosed in flexible metal reinforced conduit as
clause B1.2.
B2.8
Mechanical plant services installation
Control panels for mechanical plant will be provided as part of the Mechanical Services Contract.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
The panel will be handed to the Contractor for fixing and installation in the position as indicated on the drawings,
together with other loose items of equipment such as thermostats, detectors, etc., as scheduled in the Particular
Specification.
The Contractor shall supply and install all wiring between distribution board, control panel, and mechanical
services plant, in accordance with the contract drawings, Particular Specification Part C, manufacturers detailed
connection diagrams for both control panel and as supplied for individual items of plant.
Within plant rooms, the Contractor shall allow to install from the control panel a minimum of 50mm x 50mm
galvanised cable trunking around the perimeter walls at a suitable height for all control and circuit wiring. At a
position adjacent to each motorised valve, pump motor, motor and burner, the Contractor shall supply and
install a 16amp rated or as specified industrial type plug and socket to BS EN60309-2 for final connection and
isolation. Where convenient these sockets shall be mounted on the top or underside of the trunking, for
situations where the socket has to be placed away from the trunking, a galvanised conduit shall be installed
from trunking to socket.
Final connection between plug top and equipment, shall be carried out using butyl rubber insulated and
sheathed flexible cables, terminated using TRS type compression glands.
Connections to all other items of equipment such as temperature detectors, thermostats, pressure switches etc.,
shall either be by means of conduit, flexible conduit, butyl rubber cable as appropriate or specified.
Where SELV BMS controls are to be wired the cables must be installed in separate containment and conduits to
maintain segregation of the services. Alternatively screened 600 Volt grade insulated BMS cables may be
installed within power containment where provision and capacity has been allowed for and the screen is
correctly terminated.
All sockets, isolators, indicators (other than on the control panel) shall be clearly labelled to indicate its purpose
and operation.
No wiring shall be started until manufacturer's drawings and details are available. All connections shall be
made in accordance with manufacturer's requirements.
In addition to wiring within plant rooms, the contractor shall allow to carry out all wiring to remote mounted
detectors, motorised valves, dampers and other items of equipment as maybe detailed on the drawings and
within the Particular Specification Part C.
The Contractor shall include in the tender for attendance upon the Mechanical Services Contractor during
commissioning tests on the equipment to which the Contractor has carried out electrical installation work.
Such attendances will be periodic as required by the Mechanical Services Contractor concerned and during the
subsequent commissioning and handing over tests.
B2.9
Fan coil units
Fan assisted water coil unit heaters, will be supplied and installed in the positions indicated on the drawings by
the Mechanical Services Contractor. Heaters will normally incorporate an internal low temperature cut out to the
fan circuit, with room temperature control by means of remote mounting detector supplied with the fan coil unit.
The Contractor shall include for installing the supply to the unit, from the unit to remote controls,
sensor/thermostat, including fixing of the same and carrying out all final connections.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
Unless otherwise specified in the Particular Specification Part C, fan coil units shall be served from separate
radial circuits. Adjacent to each heater, the Contractor shall install a fused connection unit. From the
connection unit, supply and install a flush or surface conduit terminating at the heater connection position.
Wiring from the connection unit and control wiring from remote detectors shall be terminated within the
accessory box, and final connections to the heater terminals carried out using 1.5mm² heat resisting cables
enclosed in flexible conduit.
Care shall be taken to ensure the conduit box position coincides with the cable entry position in the rear of the
heater cabinet and shall liaise with the Mechanical Services Contractor to this end.
B2.10
Electric water heaters
Electric water heaters will be supplied and installed by others, with the electrical installation and connection
carried out by the electrical contractor, unless otherwise indicated in the Particular Specification Part C.
They shall be of the size and type as detailed on the drawings and within the supplementary specification.
Electric water heaters shall be wired as a separate radial circuit from the distribution board as indicated on the
schematic drawing, terminating adjacent to the water heater in a switched fused connection unit 20 ampere DP
isolating switch with pilot light and flex outlet front plate. The front plate of the switch shall be engraved WATER
HEATER.
For flush type installations, a conduit shall be installed from the switch to an accessory box with flex outlet
immediately adjacent to the cable entry to the heater. Where appropriate the conduit shall terminate
immediately behind the heater in a conduit box for direct entry.
The following flexible cables shall be used for the connection of water heaters:
Heater loading up to and including 2 kW
Heater loading 3 kW
Heater loading above 3 kW
- 3 core 1.5mm²
- 3 core 2.5 mm²
- Refer to Supplementary Specification
Cables shall be 85ºC rubber insulated HOFR sheathed flexible cord.
At every water heater position, the Contractor shall supply and install a green/yellow colour insulated earth lead
from the earthing terminal of the control switch and bond to the cold and hot water pipework, also to the waste
pipe if this is of metal construction. Purpose made bonding clamps shall be used at all bonding positions.
When water heaters are installed in a location containing a bath or shower, the installation shall comply with the
requirements of section 701 of BS 7671.
B2.11
Electric shower heaters
Shower heaters unless otherwise specified will be supplied and installed by others, but this contract shall
include for wiring and final connection.
Shower heaters shall be of the size and type as detailed on the drawings and within the specification.
Each heater shall be wired as a separate radial circuit from the distribution board.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
A local means of electrical isolation and/or a means of switching off for mechanical maintenance is required.
The shower is to be connected through a suitably positioned isolating switch being of a plate or ceiling mounted
pull chord switch. The switch shall be engraved SHOWER.
The electrical shower installation must be carried out in accordance with BS7671 and specifically the
requirements of Section 701.
From the switch, a 20mm conduit shall be installed direct into the rear of the heater, with final connection carried
out using minimum 6mm² 3 core 85ºC rubber insulated HOFR sheathed flexible cord.
The Contractors attention is drawn to clause A2.2 regarding equipotential bonding, and he shall allow to liaise
with the Mechanical Services Contractor for final position of heater and conduit entry location.
B2.12
Cooker Circuits
The Contractor shall supply and install all wiring, the method and type to be as indicated in the particular
specification.
One dedicated circuit of suitable rating is to be installed to supply each individual cooker.
One circuit may be used to supply two cookers, being an over/grill and a separate hob unit, only where they are
installed adjacent to each other in the same room. In such cases, the cookers may be connected to the final
circuit either individually by means of separate cooker control switches, or collectively by means of one such
unit common to both oven/grill and hob unit.
Cooker isolating switches are to be rated at 45 Amps and incorporate neon indicators. Cooker cable outlets
connection plates are to be rated at 45 Amps. Cooker isolating switches shall be located to one side of the
cooker not directly behind and be within 1.5m of the cooker.
Final connection to electric cookers shall be via a cooker connection unit and suitably sized cooker tails.
B2.13
Electric hand driers
Where indicated in the Particular Specification Part C, the Contractor shall supply, fix and install electric hand
driers.
Hand driers shall be wired as separate circuits from the distribution board, terminating into a H/L switched fused
connection unit. For flush installations a conduit shall be installed from the connection unit to a conduit box,
positioned to the rear of the drier for direct connection using 2.5mm² 85ºC rubber insulated HOFR sheathed 3
core cable. For surface installation a conduit shall be installed from the switched fused connection unit
terminating into a flex outlet plat and adjacent to the hand drier with final connection as above, keeping the flex
as short as possible.
The connection unit front plate shall be engraved Hand Drier. Where hand driers are installed in a room
containing a bath or shower, the installation shall be carried out in accordance with BS7671 Section 701.
B2.14
Electric heaters
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
Where indicated in the Particular Specification Part C the Contractor shall supply, fix and install electric heaters.
Electric heaters up to 3Kw shall be wired on separate circuits from the distribution board, terminating adjacent to
each electric heater in a switched fused connection unit. Final connection to the electric heater shall be by
means of 2.5mm² heat resistant 3 core cord. The length of the flexible cord shall be kept to a minimum and
shall either be securely clipped or installed within mini trunking.
The connection unit front plate shall be engraved Electric heater.
A suitable guard shall be provided to all electric heaters where small children, elderly or disabled persons are
present.
B2.15
Air conditioning units
Supplies to air conditioning units are to be three phase where possible and derived from the main plant control
panel. The air conditioning units shall incorporate soft start to alleviate large starting currents.
A local IP65 (min) isolator is to be installed adjacent to the outdoor condensing unit. A multi-core XPLE cable
shall be installed between the indoor and outdoor unit in accordance with the equipment manufacturers
requirements.
B2.16
Ventilation fan installation
B.2.16.1
General
Ventilation fans, complete with controllers where required will be supplied and installed as part of the
Mechanical Services Contract, with the exception of controllers which will be handed to the Contractor for fixing
and connection, unless otherwise specified within the Particular Specification Part C.
Where called for in the specification, the Contactor shall also allow to supply extract fans, which shall be handed
to the Main Contractor to carry out associated builders work prior to fixing by the Contractor.
All associated wiring provision and installation of fused connection units, plug and socket sets and final
connections shall be carried out by the Contractor in accordance with the drawings and specification.
Ventilation fans shall be fed from local ring circuits, unless otherwise required in the Particular Specification Part
C, to be wired as separate circuits from the distribution board or local control panel with time clock control.
Individual toilet extract units required to be activated by the lighting switch, shall be fed from that particular
lighting circuit.
The Contractor shall install a fused connection unit adjacent to each fan with the controller fed from and
mounted immediately above the connection unit.
Control wiring shall then be installed from the controller to the fan, appropriate to the method of fan mounting as
given in the following details.
Fused connection units shall have front plates engraved Ventilation Fan.
B2.16.2
Window mounted
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
Control wiring shall terminate in a surface or flush mounted flex outlet plate depending on the type of
installation, which shall be positioned centrally above or below the windows.
Final connection from outlet plate to the built in fan socket, shall be by means of multicore PVC insulated and
white sheathed flexible cord as construction ref 318-Y code H05VV-F.
B.2.16.3
Wall mounted
A conduit shall be installed from the controller, terminating into the conduit entry within the fan wall liner. A
multicore flexible cable shall then be drawn in and connected direct to the terminal block. Connection to the fan
motor is made automatically by shrouded connectors on the fascia, when the motor and impeller is fitted to the
wall liner.
B.2.16.4
Toilet units
Individual loo-vent type extract fans, shall be connected to the local lighting circuit.
Each extract fan shall have a multi pole fan isolator mounted adjacent to the unit to isolate all live conductors.
Final connection between control switch and fan, shall be by means of multicore flexible cable enclosed in
conduit direct into backplate of fan housing. Control switch to be located at high level adjacent to the fan.
Where a single fan serves several toilets and is group switched, the Contractor should refer to the Particular
Specification Part C of the particular contract.
B2.16.5
Roof mounted
Wiring from the controller shall terminate in the roof or ceiling void adjacent to the fan position in a conduit box
with fixed base connector, threaded spout entry lid and TRS gland. From the conduit a multicore 85°C rubber
sheathed and insulted HOFR cable shall be installed to the fan terminal socket. Where the cable has to pass
through duct casing between fan and ceiling, the contractor shall carefully drill a 20mm hole through the casing
and the cable taken through the hole via a TRS gland.
B.2.16.6
Industrial type
For details of control and final connection wiring to these types of ventilation units, the contractor shall refer to
the Particular Specification Part C and the particular contract drawings.
B2.17
Call systems
The Contractor shall allow to supply and install a call system as indicated in the Particular Specification Part C
and as indicated on the drawings. The call system shall be installed within accessible toilets and bedrooms,
toilets, bathrooms, corridors, lounges and dining rooms in residential homes for the elderly, children‟s homes
and special care units. The alarm should sound at an occupied station with the reset at the point of call. For
accessible toilets the reset shall be positioned adjacent to the pan and be operable from the seated position (in
case of accidental operation).
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
Accessibility toilets incorporating a shower shall have 2 pull cords and 2 reset buttons, one adjacent to the toilet
pan and the other so that it can be operated at the shower location. Unless the reset is IP65 rated it shall be
sited outside of Zone 1 where practically possible.
The call station shall incorporate a reassurance lamp, an overdoor indicator light and tone generator which shall
be installed outside of the rooms. For residential homes, wireless pager systems are preferred. All call systems
shall comply with Part M of the Building Regulations and BS8300.
B2.18
Door entry systems
The Contractor shall allow to supply and install a door entry system where indicated in the Particular
Specification Part C and on the drawings.
This shall consist of an external call station with key pad and video camera, with an internal handset with
monitor and door release. The system shall be connected to the fire alarm system so that the door is released
when the fire alarm operates and shall be „fail-safe‟ on both operation of fire alarm and power failure.
For schools, the system shall incorporate a timing device to enable staff to select times when the door is
released.
The door entry system shall be commissioned by the equipment manufacturer.
B2.19
Personal attack systems
A personal attack system shall be installed to all Social Services properties and as indicated within the
supplementary specifications and drawings. The type of system and extent of coverage will vary from property
to property and shall be as described in the Particular Specification Part C.
The personal attack system shall be installed and commissioned by a specialist contractor.
Libraries require to raise an alarm from reception desks to a staffed office area. This may be achieved by
means of a simple push and buzzer arrangement.
B2.20
Television aerial system
B.2.20.1
General
The television aerial, wiring and accessory plates will be supplied and installed as a separate contract, using a
specialist contractor to be nominated by the Consulting Engineer.
The system will be for the reception of BBC1, BBC2, ITV, ITV2, Channels 4, 5 and any other channels that may
be available for reception at that particular time. An aerial array will be installed on the roof in a position to
provide satisfactory signal reception and where possible, to meet aesthetic conditions imposed by the Contract
Administrator. The system shall be suitable for the reception of digital TV and radio signals.
Masthead amplifiers, splitter boxes etc, shall be located in accessible roof/ceiling voids, plant rooms, store
cupboards as appropriate and indicated on the drawings.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
Equipment requiring an electrical supply such as amplifiers, shall have an unswitched 13 amp socket outlet fed
from the local ring main circuit, positioned adjacent to the equipment. These shall be provided and installed by
the contractor, who shall allow to connect the plug top to the equipment supply lead. Should satellite or cable
TV be required, this shall be described within the Particular Specification Part C.
B.2.20.2
Television distribution conduits
The Contractor shall supply and install a system of 20mm conduits linking the aerial position to all amplifiers,
splitter boxes and aerial outlets as indicated on the drawings. Aerial outlets shall comprise standard flush or
surface accessory boxes, depending on the type of wiring installation specified.
For installations carried out in buildings with ceiling and roof voids that will remain accessible, conduits need
only terminate within the accessible void.
For installation with ceiling, floor and roof voids that will not be accessible after construction, a complete
rewireable conduit/trunking installation shall be installed, with draw in boxes and equipment positions sited in
locations that are readily accessible and approved by the Contract Administrator. Details of conduit/trunking
runs, sizes and location of equipment will be provided in the Particular Specification Part C and on the contract
drawings.
All conduits shall be left with draw wires for use by the Specialist Contractor.
B2.21
Telephone system
B.2.21.1
General
The Telecommunications Company will bring the service into the building and terminate. Internal wiring, supply
of all equipment, instruments and connections will either be carried out by British Telecom or such
communications company as may be nominated by the Engineer and as described in the Particular
Specification Part C.
B.2.21.2
Telephone system conduits
For inaccessible installation within ceiling, floor and roof voids a complete re-wireable conduit/trunking system
shall be installed, with draw in boxes and equipment installed in locations that are readily accessible and
approved by the Contract Administrator. Details of final conduit trunking system shall be provided in the
Particular Specification Part C or on the tender drawings.
All conduits shall be left with draw wires for use by the Specialist Contractor.
B.2.21.3
Call routing apparatus
Only approved components shall be used for direct and indirect connections to public network. No principles
need to be taken into account for supply or installation unless CRA (Call routing apparatus) is involved, Principle
L then applies. Principle L says that wiring connected to CRA must either:
Be installed in accordance with the current issue of BS 6701, or
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations

In the case of wiring installed before the current issue of BS 7601, it should then be installed in accordance
with the issue at the time
or
 Be accepted as satisfactory by the public telecommunications operator which provides the network
termination point.
B.2.21.4
Cables containing flammable materials
Telecommunications cables containing any flammable material will be either
 Terminated upon entering the building
or
 Installed within fire resistance containment.
B2.21.5
Maintenance
The telecommunications equipment and cabling shall be maintained in accordance with the installer. The
installing company shall provide maintenance cover for one year following commissioning.
B.2.21.6.
Line standards
The client is to order the equipment they require through IT orders:
IT Services Ordering Services Team
First Floor
Castle Avenue
The Castle
Winchester
SO23 8PJ
Telephone: 01962 847424
Email: [email protected]
The specialist contractor described in the Supplementary Specification shall install, connect, program, test and
commission the works apparatus.
On systems utilising structured cabling RJ45 to LJU converters shall be installed to allow telephones and
modems to be connected to the structured cabling systems.
The requirements for the majority of buildings are:







1 No. Fire Alarm monitoring line – analogue
1 No. Intruder detection monitoring line – analogue
Voice lines (numbers as required by Building User) – analogue
Data line (numbers as required by Building User) - digital
Facsimile line (numbers as required by Building User) - analogue
1 No. lift monitoring line (where a lift is installed) - analogue
Any additional lines as required by Building User e.g. payphones
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
Where practically possible the preferred method of communication for fire and intruder alarm systems to the
monitoring station is via Emizon Dual Communication System which uses internet and mobile phone
technology. Prior to the installation of any Emizon communication units, a full mobile phone signal strength test
shall be carried out to ensure suitability of this method of communication.
If the Emizon unit is installed within an intruder alarm panel, the batteries of the intruder alarm panel shall be
increased to 24 hour duration. If the Emizon unit is installed in a remote housing, the housing shall be fitted with
tamper contacts and linked to the intruder alarm panel. Interconnecting cables from the fire alarm panel to the
Emizon unit shall be carried out using a fire rated cable.
Where possible structured cabling systems are to be installed to provide added flexibility to the end user.
Patch leads for the two systems must be of different colours, e.g. Voice green and Data purple cable.
Where fax lines are utilised and out going Voice calls should be routed via the fax line to minimise out going
calls on the main line. Cabling should be a minimum standard of CW 1308 with CAT 5E utilized on structures
systems as a minimum.
It is the responsibility of the Building User to ensure the orders for the necessary lines are placed with the
relevant organisation to facilitate the installation being completed on time. However, the designer has the
responsibility to advise the Building User what lines are required and to liaise between the different parties and
ensure the orders are placed and the works are completed on time.
B2.22
IT services installation
B2.22.1
General
Cableways and cables shall be allowed for voice/data systems. Wiring shall be carried out using UTP Cat 5E
cable as a minimum. A suitably sized cabinet should be allowed for new installations, which shall also contain a
suitably sized patch panel/panels 100Mb/IGbps poe switch(s), 25% spare capacity should be allowed. A
specialist contractor should be employed to carry out the installation, connect testing and commission. A
wireless local area network shall be allowed to cover all areas.
The IT wiring shall be installed in accordance with ISO11801 standard for generic structural cabling. Cable
lengths shall not exceed 90M from the cabinet to the final outlet. All data cabling shall be OHLSF. The
contractor shall allow for 2 no. twin socket outlets on a separate radial circuit (not RCD protected) for the
communication cabinet. Any other power requirements shall be described within the supplementary
specification. The contractor shall also allow for a separate 6mm² functional earth from the main building earth
terminal.
The IT wiring shall be identified by an ivorine label engraved with a corresponding number fixed to outlet
positions at either end.
A location chart shall be fixed adjacent to the controller position within a glazed frame showing the position of IT
points and their corresponding numbers. A copy of the chart shall be provide with the maintenance manual.
All wiring shall be run within conduits, trunking or cable trays as specified, being installed separately and
segregated from other communications and mains wiring.
The Contractor should refer to the appropriate clause in the Supplementary Specification.
A surge suppression device should be included to circuits serving computers and sensitive electronic
equipment.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
B.2.22.2
Cabling standards
The voice and data cabling installation shall be installed to the following standards:
ANSITIA/EIA 568A and 568A-5
BS6701 Part 1 for voice cabling.
BS7718 for fibre optic cabling.
EN55022, IEC 801-3 & IEC 801-4 emissions and immunity.
IEEE802 11a, b, or g for wireless connectivity.
B2.22.3
Testing and certification
On completion the data installation shall be tested and certified that the installation complies to the ANSI and
British Standards tested above.
The testing and certification shall include the following:
i
ii
iii
iv
v
vi
vii
viii
ix
x
xi
Source location
Destination location
Cable/fibre number
Length of cable in metres
DC resistance
Cable impedance
Loss dB @ 100 MHz
Near end cross talk (next) @ 100MHz
Equal level far end cross talk @ 100 MHz
Graphical displays of tests
Certification of compliance with E1A/ T1A 568 – 5 –A
Functional and safety tests of fibre optic cabling should also be provided. All test results shall be provided in
hard copy format.
B2.22.4
Interactive whiteboard
The Contractor shall allow to install cable ways for the interactive whiteboards as described in the Particular
Specification Part C. Power supplies for interactive whiteboards shall be on separate circuits not RCD protected
and not connected to any emergency power off systems. Interactive whiteboards shall be installed connected
and commissioned by a specialist IT contractor.
B2.23
Fire alarm system
B.2.23.1.
General
The fire alarm and detection system shall be supplied and installed by the Contractor as indicated on the
drawings and detailed in the Particular Specification Part C. The system shall be in accordance in all respects
with the Local Licensing Authority, Fire Brigade and the following British Standard relating to Fire Detection.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
(i)
BS5839 EN54 Part 1: (latest edition) - Fire detection and alarm systems in buildings. Code of practice
for system design installation and servicing.
(ii)
BS5839 EN54 Part 25 for radio fire alarm systems. Frequency tests must be carried out for all radio fire
alarm systems at time of survey and one at commissioning and the results compared.
(iii)
Building Regulations
(iv)
Fire Reform Act
(v)
All fire alarm specialist contractors must be BAFE accredited.
The system shall be open circuit; line monitored for open circuit and short circuit faults for both zone and
sounder circuits.
All new or replacement fire alarm systems must include automatic detection.
Fire alarm equipment shall be as Apollo Fire Alarm Panels and shall be Advance 4200/5000 series or Morely
Panels unless otherwise specified in Particular Specification Part C. Fire Alarm Systems shall be of open
Protocol where devices are installed on suspended ceiling tiles, a tile suitably sized pattress shall be installed
behind the ceiling tile.
Unless otherwise agreed all new fire alarm systems shall be addressable. This shall only be deviated from for
very small systems after submitting a formal fire risk assessment and gaining approval of the Fire Safety Group.
Upon completion of the installation, the Contractor shall be responsible for ensuring that the system is tested
and commissioned by the Manufacturer's appointed representative and for demonstrating the satisfactory
operation of the system. Manufacturers test certificates including drawings indicating all devices with their full
address and phone numbers shall be included in the maintenance manual.
On completion of the fire alarm system, the electrical sub-contactor shall prepare a block diagram of sufficient
scale to show the various zones of the building covered by the fire alarm installation. On the drawing, each
zone shall be numbered/identified in accordance with the above zoning and fire alarm panel. A copy of the
diagram shall be submitted to the architect for approval. On receipt of approval, the Contractor shall mount a
copy of the drawing in a Perspex glazed hardwood frame and fix this adjacent to the fire alarm panel. In
addition the Contractor shall provide record drawings indicating location of all devices, measured sound
pressure levels and device address for addressable systems.
The use of an aspirated fire alarm system linked to the main fire alarm system shall be used to non-accessible
areas/void over 800mm.
Two core cables only shall be used for fire alarm systems, four core cables will not be permitted. Network
cables shall be enhanced cables to BS7846.
B2.23.2
(i)
Residential Premises
Standards
Fire alarm systems in Residential Properties or where people are sleeping shall be designed and installed to
conform to BS5839-EN54-Part 1 – (latest edition), and give L1 standard of cover with all areas protected by
automatic detection.
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
(ii)
Ancillary devices
Door hold open/swing free devices shall be installed on all bedroom doors and the majority of doors in general
circulation areas, i.e. corridors, lounges, dining rooms etc. 24 hour time switch should be included to allow Fire
Doors on hold open devices to close at set times. Set times to be agreed with the Property Manager.
Electro magnetic locks or keeps may be required to secure external doors. These locks shall be connected to
the fire alarm system and fail safe on activation of the fire alarm or power failure. Each lock shall be provided
with local override high level key switch to enable staff to open individual doors for general use.
Interfaces shall be provided as required to isolate mechanical plant, gas services or similar on operation of the
fire alarm system.
Similar interfaces shall be provided to isolate fixed specialist gas installations, i.e. acetylene, oxygen or similar
gases.
Where the fire alarm operation is reliant on other equipment, i.e. automatic detector mounted in ventilation
system, the airflow must be monitored by the fire alarm system. Any failure in airflow shall be indicated as a
fault on the fire alarm system.
Any system linked to the fire alarm system e.g. smoke extract systems must be monitored and failure shall be
indicated as a fault on the fire alarm system.
(iii)
Audibility levels
Some residential premises have staff led and managed evacuation and therefore a reduced level of fire alarm
audibility levels may be acceptable i.e. not 75 dbA at the bed head. The exact requirements for each specific
project must be agreed with the building manager and submitted for formal fire risk assessment and approval of
the Fire Safety Review Group.
Audibility levels in staff sleeping accommodation shall meet the requirement of BS 5839 to ensure staff are
awakened
This design strategy must be included in the fire management plan, risk assessment and staff training.
(iv)
DDA requirements
Provision may be required on the new fire alarm system to meet the requirements of the Disability
Discrimination Act. This may be provided by various methods including radio pager systems, strobes, vibrating
pads under pillows or other warning devices.
For some residential premises with staff led and managed evacuation, this may not be required. The exact
requirements for each specific project must be agreed with the building manager and submitted for formal fire
risk assessment and approval of the Fire Safety Review Group.
This design strategy must be included in the fire management plan, risk assessment and staff training.
B2.23.4
(i)
Schools
Standards
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Electrical Engineering Specification 2011
Part B: Materials and workmanship
Section B2: Installations
New fire alarms in schools shall be designed and installed to confirm to BS5839- Part 1 – (latest edition), and
give a minimum L4/M/P2 standard of cover. (L1 within multi storey SCOLA buildings).
Unless otherwise agreed all new fire alarm systems shall be „Addressable‟. This shall only be deviated from for
very small systems after submitting a formal fire risk assessment and gaining approval of the Fire Safety Review
Group.
Minimum Standards are:



In Secondary schools an 'addressable' system shall be installed.
In Primary schools either an 'addressable' or 'conventional' system shall be installed as agreed with
Hampshire County Council Fire Safety Group.
In Special schools either an 'addressable' or 'conventional' system shall be installed as agreed with
Hampshire County Council Fire Safety Group.
Fire alarm sounder shall attain dB levels as required in BS5839-Part 1 – (latest edition).
Automatic detection shall cover ground floor escape routes and all rooms with external windows that are at risk
from arson, plus any ground floor room containing a particular risk such as gas, a workshop or a significant
amount of electrical equipment.
First floor automatic detection shall cover escape routes and any room with easy access from a flat roof that has
an external window which may be considered at risk from arson, also any room containing a particular risk such
as gas, a workshop or a great deal of electrical equipment.
As a minimum automatic detection shall be provided to the following areas in addition to above:
















Staffrooms
Corridors
Circulation areas
Stairwells
Plant rooms
Kitchens
Home Economic / Food Technology rooms
Science laboratories and preparation rooms
Workshops and stores
Craft Design Technology areas
Electrical intake rooms/distribution board location
Drama rooms
Offices
Sports Halls
IT Suites
Dining Rooms
Mat Store
Heat, multi-sensor or programmable detectors may be required in some of the above locations as smoke
detection may be prone to false alarms due to the normal activities or use of these rooms.
Manual call points shall be provided to all exits in accordance with BS5839-Part 1 – (latest edition)
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Section B2: Installations
Where the fire alarm operation is reliant on other equipment, i.e. automatic detector mounted in ventilation
system, the airflow must be monitored by the fire alarm system. Any failure in airflow shall be indicated as a
fault on the fire alarm system.
Any system linked to the fire alarm system e.g. smoke extract systems must be monitored and failure shall be
indicated as a fault on the fire alarm system.
The number of manual call points should be kept to a minimum in Secondary Schools to reduce the potential for
deliberate false alarms.
(ii)
Extensions to existing systems
Where an existing system is to be extended but will not support automatic detection, a new fire alarm panel with
sufficient spare capacity to cover the whole site shall be installed and interfaced with the existing system, this
shall include three-wire systems.
All buildings shall be linked or networked to form one complete system.
Minimise management difficulties by not linking multiple conventional fire alarm panels.
Unless totally impractical the new fire alarm panel shall be located at the main entrance, interfaced to the
existing system and wired to serve the new extension.
In new entrance extensions, the fire alarm panel should be repositioned at the new entrance or a repeater panel
installed.
If extending an existing „Addressable‟ fire alarm system additional panel(s) shall be „networked‟ together to
operate as one complete system.
A separate self contained lead acid battery with charger unit shall, in the event of a power failure, provide
independent 24V DC supply for a period of 48 hours. The charger unit shall be capable of restoring the
batteries from a discharged state to a fully charged state within 24 hours.
(iii)
Class change system
Where a new fire alarm system is to be installed, the class change and fire alarm system shall not be combined
in any way.
Where possible the old fire alarm system shall be converted to a class change system. Old break glass units
shall be disconnected and removed after completion of the new fire alarm system.
Class change system wiring, junction boxes etc shall be clearly identified to simplify maintenance, including
labelling of all 230v connections.
The class change system must be reinstated on completion of a new fire alarm system.
When a new fire alarm system has been installed, the existing class change programmer shall be replaced with
a new digital programmer unless this has already been done.
For all installations, the class change and fire alarm system shall have distinctly different tones so that the fire
alarm is clearly recognisable throughout the site.
(iv)
DDA requirements
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Section B2: Installations
Provision shall be made on a new fire alarm system to meet the requirements of the Disability Discrimination
Act. This may be provided by various methods including radio pager systems, strobes, or other warning
devices.
The chosen method(s) must be agreed in advance with the building user and included in the fire risk
assessment for the property.
It may be necessary to install strobe / flashing lights in addition to sounders where there is a likelihood of loud
persistent background noise i.e. music classrooms, music practice room, plant rooms etc.
Where the use of headphones for teaching purposes is extensive i.e. in language labs, sounders shall be
supplemented with visual devices.
Requirements of the DDA shall be incorporated in the design, generally with manual call points at an accessible
level and visual indication in circulation spaces.
(v)
Other items not covered above
Manual call points in sports halls shall be installed within door reveals to avoid collision with users.
Smoke detectors and sounders within sports halls shall have protective cages over them to prevent ball
damage.
(vi)
Ancillary devices
Door hold open/swing free devices may be required to general circulation doors. 24 hour time switches shall be
included to allow fire doors on hold open devices to close at set times. Set times to be agreed with the Property
Manager.
Interfaces shall be left in plant rooms for future mechanical plant shut down, fire watch panels and in areas of
the school where gas taps are present, for future connection of isolation valves to the fire alarm system.
Interfaces shall also be provided for kitchens to enable gas cooking range and ventilation to shut down on
activation of the Fire Alarm.
Where the fire alarm operation is reliant on other equipment, i.e. automatic detector mounted in ventilation
system, the airflow must be monitored by the fire alarm system. Any failure in airflow shall be indicated as a
fault on the fire alarm system.
Any system linked to the fire alarm system e.g. smoke extract systems must be monitored and failure shall be
indicated as a fault on the fire alarm system.
Means of isolating Fire Alarm auxiliary contacts shall be provided within the fire alarm panel to prevent plant,
cooking equipment etc from being shut down during weekly testing of the Fire Alarm System.
(vii)
Phased evacuation
Fire alarm systems in schools will usually be designed to operate on single stage evacuation.
If phased evacuation is required, this may be acceptable but only after submitting a formal fire risk assessment
and gaining approval of the Fire Safety Review Group.
This must be included in the fire management plan, risk assessment and staff training.
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The property manager is responsible for planning the safe evacuation of the premises where this is adopted.
B.2.23.5
Offices, Museums, Libraries etc
New fire alarm systems in these buildings shall be designed and installed to confirm to BS5839-Part 1 – (latest
edition). and give a minimum L4.M.P2 standard of cover. (L1 within multi storey SCOLA buildings).
B.2.23.6
Ancillary devices
Door hold open/swing free devices may be required to general circulation doors. 24 hour time switches shall be
provided to enable fire door on hold open devices to close at set times. Set times shall be agreed with Property
Manager.
Interfaces shall be provided as required to isolate mechanical plant, gas services, „Firewatch‟/ MEDEM panels
or similar on operation of the fire alarm system.
Similar interfaces shall be provided to isolate fixed specialist gas installations, i.e. acetylene, oxygen or similar
gases.
Where the fire alarm operation is reliant on other equipment i.e. automatic detector mounted in ventilation
system, the air flow must be monitored by the fire alarm system. Any failure in airflow shall be indicated as a
fault on the fire alarm system.
Any system linked to the fire alarm system e.g. smoke extract systems must be monitored and failure shall be
indicated as a fault on the fire alarm system.
B2.23.7
Central Monitoring Link
The fire alarm system shall be linked to a remote monitoring station so that the Fire and Rescue Service are
called automatically outside normal hours.
This shall be achieved by installing a separate communicator (not combined with the Intruder Alarm system
unless the Intruder Alarm batteries are upgraded to a minimum of 24 hour period independent DC supply.
Where practically possible the preferred method of communication for fire and intruder alarm systems to the
monitoring station is via Emizon Dual Communication System which uses internet and mobile phone
technology. Prior to the installation of any Emizon communication units, a full mobile phone signal strength test
shall be carried out to ensure suitability of this method of communication.
If the Emizon unit is installed within an intruder alarm panel, the batteries of the intruder alarm panel shall be
increased to 24 hour duration. If the Emizon unit is installed in a remote housing, the housing shall be fitted with
tamper contacts and linked to the intruder alarm panel. Interconnecting cables from the fire alarm panel to the
Emizon unit shall be carried out using a fire rated cable.
The wiring to any remote device shall be carried out using the same type of fire resistant cabling as the fire
alarms system.
An isolating switch shall be incorporated within or adjacent to the fire alarm panel to enable testing and fire
evacuation practice to be carried out.
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Section B2: Installations
The contractor shall provide all equipment, liaison and the first years charges.
A verification certificate shall be obtained on completion to verify that the monitoring station has received the
signal. The Verification Certificate shall be inserted into the Operation and Maintenance Manual.
B2.23.8
Installation
The fire alarm installation wiring shall be of the type as specified in the supplementary specification, and shall be
one of the following with a cross sectional area of not less than 1.5mm².
Single core PVC insulated copper cables enclosed in solid drawn steel, screwed conduit, exclusively for fire
alarm wiring.
Mineral insulated copper conductor, copper sheathed cable and where oversheathed with PVC it shall be red.
Fire resistant silicone insulated cables to BS. 6387.
Sounder and zone circuits are line monitored and shall be wired in parallel, spurs or tees will not be permitted.
Circuits shall be continuous, joints only being carried out at accessory positions. Where the engineer has given
permission or deemed it necessary for joints, these shall be kept to a minimum. Joints shall consist of an
adaptable box of minimum size 100mm x 100mm, with fixed base porcelain connectors. The box shall be
securely fixed to the building fabric in an accessible position. The lid shall be fitted with an engraved ivorine
label, with white lettering FIRE ALARM on a red background.
End of line monitoring components shall be clearly marked for future maintenance and their locations indicated
on record drawings.
The fire alarm panel charger supply shall be run as a separate circuit, with a main switch finished red and
labelled FIRE ALARM DO NOT SWITCH OFF.
B2.23.9
Zoned alarms/staged evacuation
Fire alarm systems in most buildings will usually be designed to operate on a single stage evacuation.
If phased evacuation or time delay is required, this may be acceptable but only after submitting a formal fire risk
assessment and gaining approval of the Fire Safety Review Group.
The approved strategy must be included in the fire management plan, risk assessment and staff training.
The responsible person on site shall carry out planning the method of evacuation for the premises where this is
adopted.
B2.24
Lift services installation
The installation of passenger lifts will be carried out by a specialist under a separate contract.
B2.24.1
General
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Part B: Materials and workmanship
Section B2: Installations
The Disability Discrimination Act 1995 and Special Educational Needs and Disabilities Act require that we
anticipate potential barriers in the design of new buildings. In addition to providing access, we must ensure that
disabled people can safely evacuate from upper floors of premises in the event of a fire – an evacuation lift
being the most effective way to achieve this.
Passenger lifts to evacuation lift standards should be installed in all new schools and public buildings where
they have more than one storey, and where it is reasonable to expect access for people with disabilities. If this
is unachievable, the constraints should be formally documented in an Access Appraisal, agreed by the access
team.
All evacuation lifts shall be installed in accordance with BSEN 81. The layout of the building may necessitate
that more than one passenger lift be installed. BSEN81 illustrates the principle of one evacuation lift for each
designated evacuation staircase. Evacuation lifts need to be designed with a fire protected lobby at each storey
to act as a refuge area.
B2.24.2
a)
Electrical supply
Motor room lifts
A suitably sized XPL6/SWA/PVC cable shall be installed from the main switch panel or sub-main panel
(provided that suitable capacity is available) to the lift motor room terminating into an isolator adjacent to the lift
control panel. The sub-main cable shall be protected by a suitably sized MCCB in accordance with the lift
manufacturers requirement.
An additional suitably sized XPLE/SWA/PVA sub-main cable shall be provided from the main switch panel to the
lift motor/pump room and shall terminate into a six way single phase distribution board which will serve the
following:
Circuit No 1 will be used to serve a terminal box installed at a mid-point position in the shafts for lift car lights.
Circuit No 2 will serve fluorescent lighting mounted in the motor room and shafts respectively. All will be
controlled from the motor room.
Circuit No 3 will serve a 13A 3 pin switch socket outlet in the motor room, and bottom of the lift shaft for hand
tools. The circuit shall be 30mn RCD protected.
Circuit No 4 will serve electric tubular heaters controlled by a thermostat in order to maintain a temperature in
the motor room at not less than 10ºC.
Ways 5-6 spare.
The design engineer shall liaise with the specialist lift contractor for their exact requirements.
b)
Motor room less lifts
A suitably sized XPLE/SWA/PVC sub-main cable shall be provided from the main switch panel or sub-main
panel (provided that suitable capacity is available) and terminate into a BSEN60309-2 industrial type plug and
socket of the lift shaft. The design engineer shall liaise with the lift manufacturer for exact location.
B2.24.3
Secondary supplies
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Part B: Materials and workmanship
Section B2: Installations
Evacuation lifts require a secondary supply in accordance with BSEN81. This supply can be derived from the
main Supply Authorities in coming service but should not be able to be isolated with the buildings main isolator,
but be provided with its own means of isolation. Alternatively the secondary supply can be derived from a
standby generator. A suitably sized change over contactor shall be provided close to the lift control panel with a
means to isolate both supplies. A warning label shall be affixed to the change over contactor warning device is
fed from two source.
A risk assessment should be carried out in conjunction with Hampshire County Council Access Team to
ascertain the source of the secondary supply.
The sub-main cables for the secondary supply shall be Firetuf Powerplus as manufactured by Draka or
approved and equal installed on a separate fire protected route and should be separate from any other circuits.
B2.24.4
Communication
A dedicated telephone line shall be provided for each lift positioned as required by the lift manufacturer. Each
evacuation lift shall be provided with a wind crest communicator with the capacity to store several telephone
numbers. Communication shall be as described within BSEN 81.
B2.24.5
Lift car sizes
The minimum size for a lift car in a primary school should be 1,100mm wide x 1,400mm deep, with 900mm clear
opening entrance door (a lift of this size needs a half-height mirror to rear wall to assist a wheelchair user when
reversing).
The minimum size for lift car dimensions in a secondary school or public building such as a library should be
2,000mm wide x 1,400mm deep, (or to the nearest commercially available size) with an 1,100mm clear opening
lift door. NB: a lift car 1,500mm deep will accommodate most scooters.
B2.24.6
Lift call controls
The lift can be called either using lift call buttons or security cards read by presence sensors (can reduce the
risk of vandalism). Modern lifts allow for both options.
If the lift call is key pad operated, numerals should be 15-40mm across, arranged around a “pipped” 5 (assists
VI people to locate correct numerals), and spaced 10-15mm apart.
A lift landing call button should be minimum 20mm diameter or 490mm (superscript: 2) in area, be identifiable
from the face plate and by touch, and have a face plate colour contrasted from its surrounds. It should be
900mm above the floor, and at least 500mm out of any corner.
Lifts within school may require access control to prevent unauthorised use. This will be as described within the
particular specification and standard lift specification.
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Part B: Materials and workmanship
Section B2: Installations
B2.24.7
Floor call buttons
The control panel within the lift should have buttons 900-1100mm affl, on
the right hand side when entering the car, set back 400mm from any
corner.
Call buttons should be placed above alarm, door re-open and close
buttons, and be sized and contrasted as for landing buttons.
Reference/Notes
In large lifts an additional
horizontal control panel 900mm
affl can be considered mounted
at an angle so it can be seen
from standing & seated positions:
Sign Design Guide:2.8, page 63
Buttons should be legible visually and by touch, with numerals 15mm high,
and the symbol and numeral raised 1.0 - 1.5mm above the button.
When pressed, buttons should register feedback visually e.g. by an
illuminated surround lighting up and also by a sounder.
Braille should be provided to one side of the button, and just below any
longer description given of facilities on a particular floor, with a notch cut
into the edge of the sign to indicate the start of the Grade 1 or Grade 2
Braille legend.
B2.24.8
BS 8300 p 53 & 45
Lift safety systems
Voice announcement should indicate the floor level reached, on lifts serving
more than two floors.
PrEN 81-70
Audible „stand clear of the doors‟ warning should be provided to all lifts.
Infra-red curtain sensor mechanism(s) should be installed acting over a
distance of between 25mm and at least 1800mm above the car door sill
(NB: curtain sensors should cover depth of entire door opening, therefore
two sensors may be required, one on outer and one on inner face).
Support handrails to three sides of the lift , interrupted where the car
operating panel is on the same car wall, with projecting ends turned toward
the wall. The rails should be 30mm to 45mm diameter, spaced 35mm from
the wall, and with the top edge 900mm affl.
The lift car should have a stopping accuracy +-10mm to reduce tripping risk
between floor landing and lift car levels.
In case of lift breakdown, a yellow illuminated symbol and audible signal
should indicate that the alarm has been given. A green illuminated symbol
and voice-link announcement should indicate that the alarm call has been
registered.
In the event of an emergency, there should be a communication link within
the lift car to a permanently staffed area or to a central operations desk,
with an inductive coupler fitted to the lift loudspeaker for hearing aid users.
Where a person is trapped in lift, staff should be able to manually override
the lift from a lift plant room and a lift leveller provided.
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Part B: Materials and workmanship
Section B2: Installations
Best practice suggests that a means of communication is available at
dedicated refuge landings to enable Fire & Rescue Service to communicate
with Fire Marshalls or disabled people who might be waiting at a refuge for
assistance.
B2.24.9
Signage
Floor number signage should be provided to all lift lobbies on all floors,
consistently located on LH side of lift door.
Lifts should have a floor directory within the lift car indicating facilities
available on each floor.
B2.24.10
Lift shaft
Lift shaft for an evacuation lift needs to be constructed to the general
provisions of Approved Document B1: Clauses 6.40 – 6.45.
Imposing requirements relating to
the fire protection and location of
shafts and motor rooms.
Platform lifts
A passenger lift should be the first choice of installation in existing buildings
where a project involves access improvements. However, it is recognised
that in some instances specific constraints may dictate use of a platform lift,
for example in a listed building. The reasons should be documented by the
designer in an access statement or access appraisal.
Criteria for selecting a platform lift





Travel distance does not exceed 4m
Limited space in the building for a lift, motor room or pit
Prevailing construction techniques
Location capable of being suitably supervised to avoid vandalism
Limited anticipated need for lift access between floors (e.g. no
requirement for the movement of goods or use by ambulant people)
Emergency evacuation training shall be included for all passenger lifts.
B2.25
Refuge call systems
A refuge call system shall be installed to all refuges in accordance with BS5839 pt 1&8, BS5588-8 1999, Part B
of Building Regulations and DDA Regulations.
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Part B: Materials and workmanship
Section B2: Installations
B2.26
Lightning protection installation
The installation of lightning protection systems will be carried out by a Specialist Contractor in accordance with
BS EN 62305. .
Generally the air termination network and down conductor installation will depend on the structure of the
building and be achieved by one of the following methods.
a)
Copper flat tape or solid circular conductors, running from roof mounted air terminals down the outside
of the building to earth electrodes.
b)
Metal roof cladding used as an air terminal being bonded to roof steelwork and to vertical steel columns.
Vertical steel columns then bonded to earth electrodes.
c)
Metal roof cladding used as an air terminal being bonded to roof steelwork and vertical steel
reinforcement rods within structural columns. Reinforcement rods at base of columns extended out
using tape to earth electrodes.
The Contractor shall be responsible for providing a green/yellow PVC insulated copper earth bonding
cable, from the main consumers earth terminal to the lighting protection system.
Details of the cable size and location of the system bonding point, will be provided by the Specialist
Contractor and or detailed in the Particular Specification Part C.
d)
Lightning protection should be allowed for all new buildings should calculation require. Existing systems
should be extended to cover any extension to the building. Where an existing building is to be extended
which does not have lightning protection, then lightning protection need not be allowed unless the
building extension is to contain sensitive equipment.
e)
Access to all earth electrodes shall be provided to facilitate testing.
f)
Surge suppression shall be installed on lightning protection systems in accordance with BSEN62305.
B2.27
Intruder alarm
This shall consist of volumetric protection to all areas (dual technology detectors minimum). The control panel
shall be installed within a protected area with the keypad at a suitable location for staff to operate. Key operated
systems should not be used. The final entry exit point/points shall have door contacts to initiate the un-setting
count down. The system shall be connected to an approved monitoring station by means of a digital
communicator. External sounders shall be installed at suitable locations, which have been agreed with the
Contract Administrator. A verification certificate is required on completion to verify that the signal has been
received by the monitoring station. Intruder alarm panels shall be as manufactured by Galaxy. Once installed
and commissioned, the total system shall become the property of Hampshire County Council and shall not be
part of any rental agreement of any type.
All new and extended systems to have means of confirming cause of alarm (verification) either sequential, audio
or visual to the latest ACPO requirements, BSEN 50131, PD6662 and DD243. All specialist intruder alarm
installers must be NSI Gold accredited.
Most existing properties have intruder alarms which are already linked to a Central Monitoring Station and
maintained by a particular contractor. Normally any additional cover will have to be installed by this contractor.
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Part B: Materials and workmanship
Section B2: Installations
Residential properties that are occupied throughout the year may not require an intruder alarm to be installed.
External doors to residential properties may require door contacts wired back to a control panel sited within a
manned area to alert staff should a door be opened. The panel should include door on/off and mute facility. On
request from Hampshire County Council the specialist contractor shall change the engineering access codes to
0.0.0.0 to enable another chosen specialist contractor to access and maintain the systems.
B2.28
CCTV
CCTV shall be installed by a specialist contractor as detailed within the supplementary specification. The CCTV
system shall be digital with separate DVD recording equipment. The system shall be a stand alone system and
not PC windows based or transmitted over the IT infrastructure. The CCTV installation shall comply with BS
8418 and NACP 20.
The CCTV system shall be capable of being viewed over the IT network.
B2.29
Sustainable energy systems
B2.29.1.
General
All electrical installations in relation to the connection of a sustainable energy system shall be conducted in
accordance with BS7671:2008, the Electricity at Work Regulations 1989, and The Electrical Safety, Quality and
Continuity Regulations 2002.
The electrical contractor shall ensure all manufacturers guidance and recommended installation methods are
followed and executed, except where under direct instruction from the Hampshire County Council Electrical
Design Engineer. All variations from manufacturers literature shall be confirmed in writing.
B2.29.2
Access to equipment
The electrical isolation and control equipment in association with the sustainable energy system installation shall
be located either in an independent restricted access location or within the main building plant room so as to be
accessible to skilled or instructed persons only. A new white Ivorine label shall be affixed to each item of plant
to indicate its purpose as per section A2.4 of this document. Keys and access devices to the equipment shall
be issued to relevant parties as per section A1.36.3 of this document.
B2.29.3
Isolation and earthing of a sustainable energy system
Where a Sustainable Energy System is connected directly to the distributors network, i.e. has the capability to
back feed generated electricity into the incoming supply network – this installation shall be provide isolation at
the point of connection between the two services.
Local isolation shall be provided at the equipment point, either supplied with the equipment by the manufacturer
or included separately in the form of a suitably ingress protection rated switch disconnector.
Disconnection shall encompass all phases and the neutral conductor of the sustainable energy system
installation.
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Part B: Materials and workmanship
Section B2: Installations
Supplies to sustainable energy systems shall be complete with circuit protective conductors as per the
requirements of BS:7671:2008, connecting to the main building earthing terminal.
Equipotent bonding conductors shall be connected to the sustainable energy installation from the main building
earthing terminal.
If the installation is remote form the main building then the maximum earth fault loop impedance shall be
ascertained and local earthing rods shall be installed if the value exceeds that of BS7671:2008.
B.2.29.4
Synchronisation with the buildings main electrical supply
All sustainable energy systems which connect directly to the buildings electrical network shall have full
synchronisation with the supply waveforms.
his protection shall include Rate of Change of Frequency (R.O.C.O.F) and step phase angle protection, and
shall have the facility for automatic supervision delay to prevent spurious tripping during synchronising to the
main electrical service.
Light Emitting Diode (LED) indication shall be provided to indicate the cause of tripping in the event of device
operation.
B2.29.5
Induced voltages and electro-magnetic interference (EMI)
All sustainable energy systems connected to a buildings main electrical services shall be provided with
protection against the effects of induced voltages and harmonic disturbances.
This shall include protection against Electro-magnetic interference (EMI) induced by the effects of lightening.
B.2.29.6
Metering of sustainable energy systems
A new pulsed output electronic meter shall be installed to monitor any sustainable energy system providing
electrical energy to a building and/or service.
Metered values shall be recorded in kilo-watt hour (kWh) format.
This meter shall have the full facility for connection with a building management system and M-BUS controller.
Meters shall be installed adjacent to the incoming main distributors electrical services meter and labelled to
indicate its function in accordance with section A2.4 of this document.
A new RJ45 data outlet shall be installed adjacent to the meter to facilitate it future connection.
B.2.29.7
Documentation and certification
Any sustainable energy system installation shall be provided with full schematics detailing their operation and
location of all associated equipment. A copy of this schematic shall be mounted alongside the equipment
position.
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Part B: Materials and workmanship
Section B2: Installations
All original electrical certification relating to the installation shall be delivered to the Hampshire County Council
Electrical Design Engineer for approval.
All manufacturers information, schematics and certification shall be contained within the Building Operations
and Maintenance Manual.
B.2.29.8
Annual maintenance
The first years maintenance for the sustainable energy installation shall be included within the contract, the
duration beginning from the date of practical completion. It shall be the principal contractors responsibility to
ensure the electrical services in conjunction with the installation have been maintained until the end of defects
certification has been issued.
END OF SECTION B2
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