DMRC Electrical Standards &

DMRC Electrical Standards & Design Wing
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
DELHI METRO RAIL CORPORATION LIMITED
DMRC ELECTRICAL STANDARDS & DESIGN WING (DESDW)
SPECIFICATION NO.
DMES /E/0008/DMRC-LOW VOLTAGE ELECTRICAL PANELS
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
Issued on:
Date
Stage
31 July 2015
Draft-2
7th
DELHI METRO RAIL CORPORATION LTD.
Floor, B-Wing, Metro Bhawan, Fire Brigade Lane,
Barakhamba Road, New Delhi –110 001
1
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DMRC Electrical Standards & Design Wing
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
Previous Record of specification
Stage
Draft -2
Date
31-Jul-15
2
DMES-E/0008
Draft-2
DMRC Electrical Standards & Design Wing
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
DMES-E/0008
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Table of Content
1. DETAILED DESCRIPTION OF THE EQUIPMENT AND ITS APPLICATION IN DMRC: LOW VOLATGE
ELECTRICAL PANELS ...................................................................................................................................... 5
2.
GOVERNING SPECIFICATIONS ............................................................................................................... 6
2.1
STANDARDS....................................................................................................................................... 6
2.2
ABBREVIATIONS ................................................................................................................................ 9
3.
TECHNICAL AND INSTALLATION REQUIREMENT ................................................................................ 10
3.1
GENERAL AND TECHNICAL REQUIREMENTS OF ELECTRICAL PANELS............................................. 10
3.2
ELECTRICAL PANEL CONSTRUCTION ............................................................................................... 11
3.3
ELECTRICAL PANEL EARTHING AND SAFETY ARRANGEMENT......................................................... 14
4.
EQUIPMENT INSTALLED INSIDE ELECTRICAL PANELS ......................................................................... 15
4.1
BUSBAR ........................................................................................................................................... 15
4.2
POLARITY ......................................................................................................................................... 16
4.3
CONTROL SUPPLY ............................................................................................................................ 16
4.4
INSTRUMENTATION ........................................................................................................................ 17
4.5
RELAYS............................................................................................................................................. 19
4.6
EMERGENCY PUSH BUTTON (EPB) .................................................................................................. 19
4.7
INTERLOCK AND PADLOCKING FACILITIES ...................................................................................... 20
4.8
INTERNAL AND CONTROL WIRING .................................................................................................. 20
4.9
TERMINAL BLOCKS .......................................................................................................................... 22
4.10
MARSHALING UNIT ......................................................................................................................... 23
4.11
BMS INTERFACE .............................................................................................................................. 25
4.12
INDICATING LAMPS ......................................................................................................................... 26
4.13
LOW VOLTAGE SWITCHGEAR .......................................................................................................... 26
4.14
DESCRIMINATION............................................................................................................................ 35
4.15
REMOTE MONITORING ................................................................................................................... 36
4.16
MOTOR STARTER ............................................................................................................................ 37
4.17
CONTACTORS .................................................................................................................................. 46
4.18
AUXILIARY SWITCHES AND CONTACTS ........................................................................................... 48
4.19
POWER FACTOR CORRECTION EQUIPMENT ................................................................................... 48
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SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
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4.20
DETUNED FILTER ............................................................................................................................. 50
4.21
AUTOMATIC LOAD TRANSFER SWITCHES ....................................................................................... 50
4.22
DISTRIBUTION BOARDS ................................................................................................................... 52
5.
FINISHES .............................................................................................................................................. 54
6.
NAMEPLATES AND LABELS .................................................................................................................. 55
6.1
NAMEPLATES .................................................................................................................................. 55
6.2
LABELS ............................................................................................................................................. 55
7.
FOUNDATION (IF REQUIRED) AND INSTALLATION ............................................................................. 56
8.
Other Provisions.................................................................................................................................. 58
9.
SPECIAL CONDITION:........................................................................................................................... 58
10. RELIABILITY, MAINTENANCE, SPARES AND LIFE ................................................................................. 59
11. MATERIAL AND MANUFACTURING:.................................................................................................... 59
12. TESTING ............................................................................................................................................... 59
13. TRAINING ............................................................................................................................................ 60
14. INDICATIVE LIST OF ITEMS TO BE INCLUDED IN FAT PLAN FOR ELECTIRCAL PANEL. ......................... 60
15. DATA SHEET........................................................................................................................................68
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SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
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1.
DETAILED DESCRIPTION OF THE EQUIPMENT AND ITS APPLICATION IN DMRC:
LOW VOLATGE ELECTRICAL PANELS
1.1
Metro stations namely Rail corridor stations, Under-ground stations as well as ongrade stations and Depot are provided with Electrical Panels for receiving and
distribution of power supply to various usages as defined in various clauses at
voltage level of 415 V/50 Hz. The usages are generally lighting, air conditioning
system, ECS system, PD area and all other type E&M work which come under
stations coverage. Switch boards and panels as per following list are provided for
power supply distribution at metro stations and in depots.
1.2
The bidders shall refer the BOQ and drawing for incoming feeders, outgoingfeeders, indications, metering and protection details along with quantity and type
of each.
1.3
The panels are generally named as follows:
 Main Distribution Board (MDB)
 Sub-main Distribution Board (SMDB)
 Essential power panel (EPP)
 Emergency Power Panel (EMLP)
 Local Motor Control Panel (LMCP)
 Main Lighting Panel (MLP)
 Air conditioning Power panel (ACPP)
 Fire pump panel (FPP)
 Water pump panel (WPP)
 Passenger Amenities Panel (PAP)
 Light Distribution Boards (LDB)
 APFC Panel
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1.4
The manufacturing , testing , installation and commissioning of complete 415 V,
3 phase, 4 wire and 50 Hz low voltage main switchboard is as defined in IEC/EN
61439-1, built up from compartments to house busbars , terminal blocks,
internal and control wiring, instrumentation, relays, interlock and padlocking
facility, emergency push buttons, equipment for BMS/ SCADA /RS 485/ Mod bus
connectivity of communicable ACB/MCCB interface, indication lamps, control
and auxiliary switches, contacts, control power supply, air circuit breaker, MCCB,
MCB, CTs and PTs, APFCs and any other items considered necessary to deliver
the functions of incoming and outgoing power supply as detailed in BOQ and
drawing.
1.5
The equipments installed in each of the Electrical Panel are defined in the BOQ.
2.
GOVERNING SPECIFICATIONS
Electrical Panels along with equipments shall conform to the latest standard or
harmonize as per the respective standard as given below or specified along with
the equipment in the specification.
In case of any conflict between specifications & the standards, the
instructions/decision of the Engineer' or Employer's authorized representative
shall be binding.
2.1
STANDARDS
Low voltage Electrical Panels shall satisfy the following requirements and shall also
comply with standards in force when Electrical Panel units are manufactured,
particularly which are in the following table (Unless otherwise stipulated in the
specification, the latest version of the standards shall be applicable)
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SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
STANDARD
ISO STANDARD
ISO 9001
IEC STANDARD
IEC 60228
IEC 60255
IEC 60529
IEC 60831
IEC 60871
IEC 60898
IEC 60947-6-1/EN 60947-6-1
IEC 60947-2/EN 60947-2
IEC 60947-1
IEC 61008
IEC 61439-3/EN 61439-3
IEC 61439
IEC 62262
IEC 61641
IEC 61869/BSEN 61869
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DESCRIPTION
Quality systems- model for quality assurance in
design/development, production, installation and
servicing
Conductors of insulated cables
Measuring relays and protection equipment
Degrees of protection provided by enclosures (IP
Code)
Shunt power capacitors of the self-healing type for
a.c. systems having a rated voltage up to and
including 1000 V
Shunt capacitors for a.c. power systems having a
rated voltage above 1000 V
Electrical accessories – Circuit-breakers for over
current protection for household and similar
installations
Specification for low-voltage and control gear
Multiple function equipment. Automatic transfer
switching equipment.
Specification for low-voltage switchgear and control
gear circuit breakers
Specification for low-voltage switchgear and control
gear. Contactors and motor-starters.
Electromechanical contactors and motor-starters.
Residual current operated circuit-breakers without
integral over current protection for household and
similar uses (RCCBs)
Specification for low-voltage switchgear and control
gear assemblies. Particular requirements for lowvoltage switchgear and control gear assemblies
intended to be installed in place.
Specification for low-voltage switchgear and control
gear assemblies
Degrees of protection provided by enclosures for
electrical equipment against mechanical impacts(IK
code)
Enclosed low-voltage switchgear and control gear
assemblies - Guide for testing under conditions of
arcing due to internal fault
Instrument transformers
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DMRC Electrical Standards & Design Wing
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
IS STANDARD
IS 13779
IS 13947-5-2
IS 13947-5-1
IS 13947-4-1
Is 13947-3
IS 13947-2
IS 13947-1
IS 5553
BS STANDARDS
BS 381 C
BS 4800
BSEN60742/BS
61558
BS 1432
BS 951
DMES-E/0008
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ac Static Watt-hour Meters, Class 1 and 2
Low-Voltage Switchgear and Control gear, Part 5:
Control Circuit Devices and Switching Elements,
Section 2: Proximity Switches
Low-Voltage Switchgear and Control gear, Part 5:
Control Circuit Devices and Switching Elements,
Section 1: Electromechanical Control Circuit
Low-Voltage Switchgear and Control gear : Part 4 Contractors and Motor-Starters
Low voltage switchgear and control gear, part 3:
switches, disconnectors, switch-disconnectors and
fuse combination units
Low-Voltage Switchgear and Control gear, Part 2:
Circuit Breakers
Low-voltage switchgear and control gear, Part 1:
General rules
Reactors – Specification
Colour chart
Colour
3535/BS Isolating Transformers
Specification for Copper for electrical purpose high
conductivity copper rectangular conductor with
drawn or rolled edges.
Electrical earthing. Clamps for earthing and bonding.
Specification
BS 7430
Code of practice for protective earthing of electrical
installations
BS EN 13601
copper and copper alloys - copper rod, bar and wire
for general electrical purposes
Specification for low-voltage switchgear and control
gear. Contactors and motor-starters.
Electromechanical contactors and motor-starters.
Hot rolled products of structural steels
Electric cables. Low voltage energy cables of rated
voltages up to and including 450/750 V (U0/U)
IEC/BS EN 60947-4-1
BS EN 10025
BS EN 50525
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SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
2.2
ABBREVIATIONS
ACB-Air circuit breaker
ALTS- Automatic load transfer switch
APFC-Automatic power factor correction
ATS- Automatic transfer switch
DB- Distribution board
EMC- Electromagnetic compatibility
LEP- Local Electrical Panel
LMCP- Local motor control panel
LT- Low Tension
LVDB-low voltage distribution board
ELECTRICAL PANELS- Low Voltage main switch board
MCB- Miniature circuit breaker
MCCB-moulded case circuit breaker
MFM- Multi function meter
MPCB-Motor protection circuit breaker
RCCB- Residual current circuit breaker
RTU- Remote terminal unit
SELECTRICAL PANELS- Sub Main Distribution Board
TB- Terminal block
VFC- Volt free contact
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3.
TECHNICAL AND INSTALLATION REQUIREMENT
3.1
GENERAL AND TECHNICAL REQUIREMENTS OF ELECTRICAL PANELS
3.1.1
The Electrical Panel shall be same as low- voltage switchgear and control-gear
assemblies defined in IEC 61439-1 or EN 61439-1 built up from compartments
housing circuit breakers, control gear, relays, bus bars, controls and other
equipment as defined in BOQ.
3.1.2
All panels should be factory built of proven design with OEMs as well as
switchboard manufacturer approved as covered by clause 3.10 of IEC 61439-1.
3.1.3
The Electrical Panel shall pass the internal arc fault containment tests in
accordance with IEC 61641 for fault current ratings as defined in BOQ for a
minimum time of 0.3 sec.
3.1.4
The degree of Ingress Protection for Electrical Panels shall be IP 54 for
underground and IP 42 for Elevated/Depot unless otherwise specified in BOQ, as
defined in IEC 60529 which shall not deteorate with time.
3.1.5
The Electrical Panels and the associated equipment, including switchgear and
control gear assemblies shall be certified for the category of duty specified as per
Annex A of IS/IEC 60947-1.
3.1.6
The main circuit as defined in vide clause 3.1.3 of IEC 61439-1 shall have an
insulation voltage of 1000 V AC or as specified in the BOQ.
3.1.7
The ambient temperature and ambient humidity for Electrical Panel shall be as
per IEC 61439-1 (clause 7.1.1 and 7.1.2 of IEC 61439-1) and Switchgear shall be as
per IEC 60947(Clause 6.1.1 and 6.1.3 of IEC 60947).
3.1.8
The secure service life of Electrical Panels shall be at least 30 years as defined in
General Scope of Work. The design features to secure the service life of 30 years
shall be submitted at the time of design approval.
3.1.9
The Electrical Panel shall have a rated short time withstand current of 70 kA, 65
kA, 50 kA and 35 kA for 1 second as per BOQ.
3.1.10
The Electrical Panels shall be a minimum of Form 4b Type 5 in accordance with BS
EN 61439-2/IEC 61439-2 & Eiema’s Guide To Forms Of Sepration.
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3.2
ELECTRICAL PANEL CONSTRUCTION
3.2.1
The panels shall be of the approved design to suit local conditions as prevailing at
different metro stations.
3.2.2
The Electrical Panel ( other than DB) shall be designed for indoor use in the form
of free standing, floor mounting extendible, self contained, flush fronted cubicles
and sectionalized as necessary to face easy transportation and erection,
containing all the equipment indicated on the Drawing, BOQ and specified
hereinafter.
3.2.3
The cubicle section shall be constructed of angle iron types frames or folded sheet
steel or fully welded/bolted construction with all necessary removable covers.
Removable lifting lugs shall be provided on the top of the cubicles. Cubicle sections
shall be provided with bolts or devices for insuring that they are correctly aligned
when being coupled together. The bus bar chamber shall be fitted with removable
end cover plates secured by mild steel captive screws.
3.2.4
It shall be finished to provide a rigid shell type of enclosure in accordance with BS
EN 10025.
3.2.5
The load bearing parts of the entire electrical panel assembly shall be 2 mm CRCA
thick sheet whereas other partition parts shall be constructed of minimum 1.6 mm
CRCA thick sheet steel.
3.2.6
The Electrical Panels shall be mounted on a robust base frame made up of steel
channel with a minimum height of 100mm and the maximum height of Electrical
Panel shall not exceed 2.40 meter including base frame. The base frame shall be
able to withstand the static and dynamic loads of the Electrical Panels. The steel
channels shall be painted with epoxy polyester paint. The main contractor shall
ensure that the maximum height of the Electrical Panel at the site of installation
shall not exceed 2.6 meter including foundation if any.
3.2.7
Electrical panel shall have provision for top/bottom in-coming and bottom/top
out-going to suit site conditions of cable entries.
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3.2.8
Non-magnetic gland plates of not less than 5 mm thick of suitable size shall be
provided at the top and bottom of the LV main switchboards for the termination
of incoming and outgoing power cables of size 120 sq. mm or more or bus ways
and 3 mm thick for cables of size less than 120 sq. mm. Where armoured multicore cables terminate inside the switchboard enclosure, glanding plates or
glanding brackets shall be provided for securing the cables to the switchboard.
3.2.9
Glanding plates, glanding brackets and extension boxes shall be removable and
shall be of adequate size for the particular cables to be terminated. The cables
shall not put any stress on to the glanding plate and shall be secured adequately.
3.2.10
All relays and indicating instruments shall be at least 300 mm and not higher than
1.8 m from base frame. The clearance in front, back and side of all assemblies of
switchgear and control gear shall be as per IE Rule 51.
3.2.11
Various units comprising a complete Electrical Panels shall be grouped in a multitier arrangement including a cabling and wiring chamber of ample dimensions to
accommodate terminal blocks, cable boxes and gland plates.
3.2.12
The equipment shall be arranged within each compartment such that all normal
maintenance can be carried out through hinged access doors or removable covers,
and where possible from the front.
3.2.13
Adequate maintenance access shall be provided to equipment within the
Electrical Panels. Demountable panels shall be provided at the back of the
Electrical Panels that can be handled by a single person. Every demountable panel
shall be provided with a pair of handles for easy removal and fixing.
3.2.14
Front access door shall be fixed with concealed hinges and interlocked with the
switch mechanism. The door panel can be opened only if the switchgear is in the
"OFF position” or the switchgear should switch off if the panel door is opened.
3.2.15
Ventilating louvers along with filter, where required, shall ensuring compliance of
IP 54. It shall be provided in such a way that it is easily accessible for cleaning or
self cleaning filters shall be proved.
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3.2.16
Anti-condensation heaters shall be provided at the rate of 60 W for each vertical
of the Electrical Panels, incase the volume is greater than 1 cubic meter of one
vertical then 2x60 W heater shall be provided. The heaters shall be of an enclosed
tubular pattern, each separately fused/ MCBs and switch. Each heater shall be
controlled by means of a step adjustable humidistat.
3.2.17
Adequate arrangements for air circulation shall be made within each
compartment of the Electrical Panels, if required. The Contractor shall ensure that
the internal temperature of the Electrical Panels will be well within the operating
ranges as specified by IEC 61439-1 of all electric components including switchgear,
control gear, bus bars, relays, wiring and timers inside the Electrical Panels.
3.2.18
All the incoming / outgoing terminations shall be extended via copper connections
into a separate termination chamber adjacent to the switchboard. When busbars
are used between switchboards, the internal busbars of the switchboard shall be
of tinned copper bars sizes of copper shall be as per tested design. No linking of
busbar or incoming/outgoing terminals with switchgeras/functional units shall be
permitted with cable except in case of MCCBs./MCBs below or equal to 100 Amps
rating.
3.2.19
The switchgear assembly/sub-assemblies or panels shall be termite and rodent
proof.
3.2.20
The switchboard shall have sufficient space to house all electrical equipment
allowing spare Space capacity of 10% for the future expansion if specifically asked
in BOQ
3.2.21
Spare feeder shall be provided as per BOQ. Any Panel which comprises an
assembly of similar modules shall be constructed such that further similar
modules can be added at either end.
3.2.22
All similar items of the Electrical Panels and their component shall be
interchangeable. Spare parts shall be manufactured to originals and shall fit all
similar items of the Electrical Panels. Where machining may be needed before
fitting renewable parts, the machining fits and the associated tolerances shall be
shown on the drawings accompanying the instruction manuals.
3.2.23
The Electrical Panel shall operate without excessive vibration and with a minimum
of noise as per best of engineering practice and shall also operate without
excessive temperature rise at the rated load conditions.
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3.2.24
The style and finish of the workmanship shall be consistent throughout the
Works. Unless otherwise specified, Engineer shall decide the final colours for all
paintwork and other finishes to be applied to the Electrical Panels.
3.3
ELECTRICAL PANEL EARTHING AND SAFETY ARRANGEMENT
3.3.1
All non-current carrying metallic components shall be permanently connected to
earth.
3.3.2
Material used for the earthing busbar shall be same as the main busbar.
3.3.3
The tin-plated copper/aluminium earthing busbar inside the panel shall have
cross-sectional area as per calculation given in Annex B.
3.3.4
A continuous earthing busbar shall be provided along the whole length of each
Electrical Panels and shall be provided with terminals for connection to the metal
housing of incoming busways, cable trunking and cladding or armouring of all
incoming and outgoing cables and to the substation earth.
3.3.5
Switchboards shall be provided with two earthing terminals, one at each end, for
the connection of external earth conductor for earthing. The earthing bars shall
be fixed at rear interior bottom portion throughout the length of the switchboard,
bonding all gland plates, and other component parts of the switchboard to a main
earth point adjacent to the intake position in accordance with BS 951 and BS 7430.
3.3.6
All terminals, connections, relays and other components which may remain live
when access doors are open shall be screened. It shall not be possible to obtain
access to an adjacent cubicle when any door is opened.
3.3.7
Where several outgoing circuits occupy a common cabling chamber, all copper
work, cable lugs, terminations and terminal blocks shall be fully segregated by
compartmentation to enable work on any one circuit to be carried out with other
circuits remain live.
3.3.8
Protection against shock in normal service shall be achieved by the provision of
barriers or enclosures both vertical and horizontal and between adjacent units to
ensure segregation and prevent accidental contact with live parts, or by complete
insulation of all live parts Control cables shall be segregated from primary
conductors.
3.3.9
The protective earthing configuration shall be TN-S unless otherwise specified.
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EQUIPMENT INSTALLED INSIDE ELECTRICAL PANELS
Electrical panels consist of Low Voltage Switchgear, control wiring and all other
parts which are defined below.
4.1
BUSBAR
4.1.1
Busbars shall be of rectangular section hard drawn high conductivity tinned
copper bare type conform to BS 1432/13601 or aluminium as per BOQ, adequately
rated for designed value and fault level of load as per BOQ and supported by nontracking moulded insulators spaced at suitable intervals. The complete assembly
shall be capable of withstanding the maximum mechanical stresses to which it
may be subjected to under fault conditions.
4.1.2
Sizing of the busbar shall comply with IEC 60890 for temperature rise assessment
by extrapolation and in case of copper busbar temperature rise as per Copper
Development association latest formula, may also be used.
4.1.2.1
Bus bar rating shall be same through out the length of panel and shall be as per
BOQ type tested design and recommendation of IEC 61439. The bus bar shall be
designed for easy extension in future at either end.
4.1.3
Busbars and busbar connections shall be constructed in accordance with the
requirements of IEC 61439-1. The short-time withstand current rating shall be as
mentioned in BOQ for 1 second at 415 V.
4.1.4
Connection in Bus bars shall be made as approved and proven design of original
manufacturer.
4.1.4.1
The maximum temperature of the bus bars and the bus connections shall be as
per IEC 61439 standard.
4.1.5
The main busbars shall be so positioned and arranged that all busbar risers and
droppers can be brought onto the main busbars without undue bending. Busbars
shall be and supported with appropriate clearances in air to the requirement of
providing full insulation.
4.1.5.1
Busbar chambers of similar rating shall be capable of coupled together using
busbar coupling links, in accordance with the manufacturer's recommendation.
Coupling links shall be approved by the Engineer before use.
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4.1.5.2
Interconnecting conductors between busbar chambers and switchgear shall be as
per rating of switchgear and type tested design.
4.1.5.3
Switchgear shall be joined to busbar chambers by means of properly designed
busbar chamber connection flanges or conduit couplers and male bushes.
Connection flanges shall be manufactured from galvanized sheet steel or CRCA
and finished grey.
4.1.6
Busbars shall be coloured for phase identification at location of bus inspection
points with the approval of site Engineer. The material for phase identification
shall be non-fading colour of proven design to be decided by the Engineer and use
of adhesive label shall not be acceptable.
4.1.6.1
The front cover and end plates of busbar chamber shall be removable and
normally held in position by non-ferrous metal screws.
4.2
POLARITY
4.2.1
The polarity of all apparatus shall be arranged as follows when viewed facing the
front of the Electrical Panels:
a) For two pole apparatus, phase pole and neutral pole when reading from top
to bottom or left to right; and
b) For three or four pole apparatus, red, yellow and blue phases and neutral
when reading from top to bottom or left to right.
4.2.2
All cables shall be so connected within the Electrical Panels such that the correct
sequences are preserved throughout.
4.3
CONTROL SUPPLY
4.3.1
Separate control bus of suitable rating made of copper shall be provided through
out the panel length, and the control bus should be accessible from the front/back
of the panel. Control voltage taping for different feeder shall be done with proper
clamp.
4.3.2
The control circuit shall be separated from other auxiliary circuits, i.e. indicating
circuit, heater and lighting circuits, with dedicated circuit protective devices.
4.3.3
240V control supply will be available from the station UPS with standby utility or
as decided by engineer at site. DP MCB protection shall be provided at incoming.
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4.3.4
240V Volt sensing relay with volt free contacts shall be provided for sensing the
control supply for local and remote indication to BMS/SCADA.
4.4
INSTRUMENTATION
4.4.1
Electrical meters shall conform to IS 13779 / IEC - 1036, 687, 1286 suitable for
single phase /three phase supply system in all respects. Accuracy of meters shall
be of class as specified in BOQ.
4.4.2
All meters shall be digital type and multifunction meters should be with RS 485
connectivity to suit BMS System wherever mentioned in BOQ. Suitable memory
and software for logging the information along with real time metering
information must be available. The meters must have required level of protection
and sufficient number of auxiliary contacts.
4.4.3
Meters shall be suitable for continuous operation as per IEC 898.
4.4.4
Meter shall be suitable for 3 phase, 4 wire systems, balanced as well as unbalanced
load. All instruments and associated apparatus shall be capable of carrying their
full-load current without undue heating. They shall not be damaged by the
passage of fault currents up to the rating of the associated switchgear through the
primaries of their associated instrument transformers. The instrument meter shall
be earthed by a conductor of not less than 2.5 mm2 cross-sectional area.
4.4.5
Energy meters shall be two / three element, switch board mounting type suitable
for unbalanced loads. In case of two incoming feeders, a summation C.T. shall be
provided with the meter.
4.4.6
The display for meters i.e. ammeter, voltmeters or multifunction meter shall be
auto-ranging type.
4.4.7
Selector switches shall be inbuilt in Voltmeter such that voltmeters can read
voltages between phase and phase and between phase and neutral.
4.4.8
Ammeters shall normally be suitable for 5 A secondary of current transformers
4.4.9
Voltmeter circuits shall be provided with protection through MCB as required.
4.4.10
Separate current transformers for a feeder shall be provided for protection device
and for instrumentation.
4.4.11
Current Transformers (CTs) and Voltage Transformers (VTs)
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4.4.11.1
CTs and VTs shall comply with IEC 61869/BSEN 61869 and CTs shall be of the epoxy
resin encapsulated ring type. The ratings specified on the Drawings are indicative
only and it shall be contractor/manufacturer's responsibility to ensure that the
ratings offered are adequate for the relays/meters provided considering lead
resistance, etc.
4.4.11.2
Current transformers shall comply with approved standard and shall be
compatible with and provide the necessary accuracy, over current factors,
characteristics, performance and VA rating for the satisfactory operation of the
relevant protection devices, instruments and meters.
4.4.11.3
All CTs shall have a short-time current rating as specified in IEC 60044-1.
4.4.11.4
CTs for protection shall be compatible with the protection relays to ensure that
the CTs will not be saturated up to the maximum prospective fault current.
4.4.11.5
CTs designed for unit protection schemes shall be able to withstand a stability of
not less than the maximum through-fault of the units.
4.4.11.6
In balanced circuits, the spill current with maximum stability conditions shall not
exceed one quarter of the operating current of the relay.
4.4.11.7
CTs for use in conjunction with protection relays shall be of class 5P accuracy or
better. CTs for use in conjunction with measuring instruments shall be of Class 1
accuracy. The product of rated accuracy limit factor and rated output of the
protection CTs shall not be less than 20 times the total rated burden of the trip
circuit including the relay, connection leads and O/C release where applicable.
4.4.11.8
All CTs shall have output ratings adequate to cater for the burden connected to
them. The Contractor shall demonstrate to the satisfaction of the Employer
representative. By calculation or by test, that each group of the CTs, when
installed and having the secondary burden connected, is capable of operating the
relays and other measuring instruments in accordance with the manufacturer's
published characteristics and the requirements of the system, with a reasonable
margin of safety.
4.4.11.9
Measuring CTs shall be connected to test terminal block. The test blocks shall be
provided with easily removable links and designed to facilitate connection of
testing instruments on load without open-circuiting the CTs.
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4.4.11.10
The secondary circuit of each set of CTs shall be earthed at one point only through
a disconnectable copper link at a readily accessible position for testing.
4.4.11.11
Multi-ratio CTs (where used) shall have a label clearly indicating the connections
required for the alternative ratios. These connections shall be shown on panel
wiring diagrams.
4.4.11.12
Identification labels shall be fitted, mentioning type, ratio, rating, output and serial
numbers.
4.4.11.13
VTs shall be provided with adequately rated primary and secondary fuses.
4.4.12
Instruments shall be similar in appearance throughout the whole of the Electrical
Panels. All instruments, meters shall be of flush pattern, dust and moisture proof,
suitable for the environment in which they are installed.
4.4.13
All instruments and meters shall be completely segregated in instrument
compartments. Compartments containing these devices shall not contain any
terminals or equipment operating at higher voltages with the approval of site
Engineer.
4.4.14
The housing shall be of steel or phenolic mould. Design and manufacture of meters
shall ensure prevention of fogging of instrument glass. Selector switches shall be
provided for ammeters and voltmeters used in three-phase system. This selector
shall be of built-in type with meters.
4.5
RELAYS
4.5.1
The relays are having in-built function with protective gears such as ACB, MCCB
and MCB and MPCB etc. In case any relay is required for additional protection as
stated in BOQ or otherwise, the same shall be provided to ensure full protection
to the system.
4.6
EMERGENCY PUSH BUTTON (EPB)
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4.6.1
Emergency lock and key type push buttons shall be installed wherever required or
specified in BOQ to de-energize the Electrical Panels in the event of an emergency.
The EPB shall be button type with flat surface protection guard ring and pressedin design with key reset so that accidental triggering and vandalism shall be
avoided as far as possible. Transparent hinged cover shall be provided in front.
Unless otherwise specified on the Drawings, the EPB shall be mounted at 1300 +
100 mm above finish floor level. The button design and the installation details shall
be submitted for approval.
4.7
INTERLOCK AND PADLOCKING FACILITIES
4.7.1
Mechanical key interlocks shall be provided wherever applicable or as specified in
BOQ and shall be so designed as to avoid mal-operation at the point of manual
application. The scheme shall be such that attempts to remove a captive key shall
not result in tripping or opening of the device.
4.7.2
The tripping of the ACB(s) shall be via local hard wiring control and in Signal(s) shall
also be generated from circuit breaker(s) upstream of the corresponding Electrical
Panels and the switchboard interconnected section ACB.
4.7.3
Electrical interlocks on withdrawable equipment shall be so arranged that if the
equipments are withdrawn, the complete operation of the withdrawn equipment
shall be independent of the remote interlocking contacts. In addition, interlocks
shall not be defeated leading to damages or unsafe operations of Electrical Panels
due to the withdrawing of equipment.
4.7.4
Locking facilities shall be provided where appropriate for switches and isolators in
order that they may be locked in the open position. Switchgear cubicle access
doors shall be equipped with integral type locks, preferably incorporated in the
handles of the equipment.
4.7.5
Where locking facilities are of the integral barrel type, the key for each lock shall
be unique to the associated lock unless otherwise specified.
4.7.6
Two keys shall be provided for every lock supplied. The keys shall be fitted with
rings with identification labels, and cabinets with glazed front- opening doors shall
be provided. The cabinets shall be adequate in size and equipped with hooks to
house all keys when not in use, and shall be mounted in positions to be decided.
4.8
INTERNAL AND CONTROL WIRING
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4.8.1
All equipment shall have adequate provision for the entry and termination of all
associated power and auxiliary cables.
4.8.2
Cable entry shall in all cases, except where otherwise specifically approved, and
be at the base of the equipment. All cabling and wiring within the Electrical Panels
shall be neatly run and fitted in or upon such cable trays, trunkings and conduits
as may be appropriate to the layout and equipment. Cable trays, trunkings,
conduits and cleats shall be non - metallic and shall be of the low smoke halogen
free material. Metallic cleats is acceptable with the approval of the site Engineer.
4.8.3
LSZH and Fire Survival Cables shall be as specified in Section E02 (BS 6724multicore cable and BS 7211 for single core cable) of this Specification. All internal
and control wiring shall be Low Smoke Zero Halogen (LSZH) copper conductor
wires rated at 450/750 V complying with BS EN 50525 for this Specification. All
control wiring within the Electrical Panels shall be with single core minimum 2.5
mm2 for CT and balance as per approved manufacturer design. Insulation shall
have a glossy finish, be resistant to oil and be incapable of supporting combustion.
Fire Survival wires shall be provided as per BOQ.
4.8.4
Wiring from the fixed part of the switchboard to the movable part such as hinged
door shall be enclosed by flexible tubing made of Low smoke Zero Halogen
material. Exposed live terminals shall be suitably shrouded or covered.
4.8.5
Wiring passing out to fully accessible positions shall be run in non-metallic low
smoke halogen free flexible tubes or conduits.
4.8.6
All internal wiring shall be neatly run and securely fixed in non-metallic cleats in
such a manner that, wherever practicable, wiring can be checked against diagrams
without removal of the cleats.
4.8.7
Access opening shall be fitted with a suitable long lifegrommet where inter-panel
wiring passes through panel side sheets etc.
4.8.8
Bus-wires shall be fully insulated. Bus-wires terminals shall be fully accessible from
the point of entry to each enclosure. MCB and links shall be provided to enable all
control circuits within the Electrical Panels to be isolated from the bus-wires.
4.8.9
All control circuits shall be protected by a MCB.
4.8.10
There shall be no joint in conductors between terminal points.
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4.8.11
Terminations for terminals shall be of the crimped-on ring type. Terminations of
stranded conductors to clamp type terminals shall be of the crimped-on solid rod
type.
4.8.12
No more than one core of either internal or external wiring shall terminate on any
outgoing terminal. Where duplication of terminal blocks is necessary, suitable
solid bonding links shall be incorporated in the design of block selected.
4.8.13
Wiring for all known future equipment shall be provided and all wires shall be
terminated.
4.8.14
All wires between the terminals of two equipment shall be given a unique number
according to an approved system. A wire number shall not change solely by virtue
of passing through, say, a marshalling terminal block.
4.8.15
In the interests of uniformity, the wire-numbering system shall be approved by
the Engineer.
4.8.16
Identification markers shall be fitted to all wires and multicore cable tails within
enclosures in accordance with the diagram for apparatus concerned. Cable and
core makers shall be of insulation material, colored according to the wire
numbering system with a glossy finish, be resistant to oil and be incapable of
supporting combustion. Numbers shall not be duplicated unless the
corresponding wires are directly in series or parallel
4.8.17
Different insulation colours shall be provided to distinguish the various circuits. All
wiring shall conform to the colour and ferrule codes to be approved by Engineer.
4.9
TERMINAL BLOCKS
4.9.1
Both incoming and outgoing cable shall have top or bottom entry depending on
site requirement.
4.9.2
Each terminal block compartment shall have not less than 20 % or 4 spare
terminals whichever is greater.
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4.9.3
Terminal blocks for low voltage wiring shall be moulded from high-grade nonhygroscopic melamine, comprise bank of rail-mounted blocks with all live parts
fully shrouded, screw- clamp, spring loaded insertion, solder-lug or stud type
terminals as appropriate to the design and duty of the cables to be terminated.
Pinch-type screws, where the screw is in direct contact with the conductor, shall
not be used.
4.9.4
Each terminal shall be provided with claw-type washers, crimp lugs or other
approved means for connection of the wires. Plain and spring washers, nuts and
lockouts shall be electro-tinned.
4.9.5
Terminals shall be assembled in banks and each terminal shall be complete with
marking tags to fit into moulded tag slots.
4.9.6
Terminals for final connections for indication, instrumentation and metering
circuitry shall have test probe facilities and an integral disconnecting device to
facilitate testing.
4.9.7
Terminations shall be grouped according to function and no more than two wires
Connected to one terminal. Labels shall be provided adjacent to the terminal
block to identify the function and voltage of each group.
4.9.8
All terminals to which 240 V or 415 V AC circuits are connected, where they are in
individual terminal blocks, shall be provided with a transparent insulated cover
which in addition to any other form of identification and shall have a label
engraved suitably indicating the voltage.
4.9.9
Terminals for the control supply which may be still alive when the main equipment
is isolated from the mains supply shall be suitably labelled to reduce the risk of
accidental contact.
4.9.10
All terminals shall bear a permanent identification number or letter.
4.10
MARSHALING UNIT
4.10.1
In main distribution Electrical Panels separate marshalling chamber shall be
provided for BMS interfaces terminals or wherever required as per BMS
requirement.
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4.10.2
Single location interface for different LV components of main distribution panel
(DB100, DB200) or other Electrical panel where ever necessary or as per BOQ shall
be provided through marshalling chamber for BMS interface.
4.10.3
All interface terminals and ports for BMS shall be wired up to the marshalling
chamber. Necessary marking and ferruling shall be provided for individual
termination.
4.10.4
Control command interface and other terminals having potential should have due
separation from VFC interface terminals. Control and signal cable wiring from
different relays, sensors, transducer, controller and contactor releases shall be
through separate wiring bunch to avoid fault current or external magnetic/
electric interface.
4.10.5
Necessary multi dropping and single point interface provision shall be done
through suitable short links. Communicable devices using standard protocol
communication shall be looped as per BMS requirement.
4.10.6
Marshalling chamber should have provided with necessary mounting
arrangement or space provision for BMS remote I/O module/ PLC equipment
along with its associated interface equipment and power supply unit or as per
BOQ.
4.10.7
Connecting cable with connector between ACB communication unit and junction
box shall be provided.
4.10.8
24V DC source unit or as required (Incoming supply shall be taped form the control
supply available in the panel) for communication of ACB/MCCB with SCADA/BMS
system.
4.10.9
Panel manufactures shall provide the required termination and interface detail for
BMS work. In case of requirement of supervision and guidance during BMS
commissioning, same shall be inclusive to the panel manufacture's scope of work.
It is the responsible of panel manufactures to provide necessary interface detail
such as data point register address during BMS commissioning or supervise as
appropriate during installation and testing of BMS system.
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4.10.10
Marshalling box shall comply with EMC (electromagnetic Compliance) and
protected from any electrical or magnetic interface. Required protection against
any BMS or panel component has to be inclusive to respective contractor’s scope
of work.
4.10.11
Any specific interface requirement not specified here with shall be wired upto the
marshaling chamber interface terminal. BMS/SCADA interface point should only
confine to marshalling box.
4.11
BMS INTERFACE
4.11.1
Electrical contractor shall cross reference the requirement of BMS remote control
and monitoring interface as required for electrical equipments and shall provide
the necessary volt free contact and remote control interface for BMS.
4.11.2
Serial interface as applicable for ACB/MCCB and digital meters or MFMs shall be
strictly on standard protocol communication (preferable with MODBUS-RTU,
RS485, 2 wire communication). Necessary interface detail and drawing shall be
provided to BMS contractor during commissioning.
4.11.3
All terminals and BMS interface terminal and ports shall be wired to a separate
chamber with adequate number of ITBs and with proper marking as per interface
document.
4.11.4
No such change in contact or pseudo signal shall be provided for critical alarms
control interface.
4.11.5
BMS and PLC interface for control command shall be pulse type close contacts for
single command output / double command output or a variable voltage/current
(i.e. 0V- 10V or 4mA - 20 mA) for analog output command.
4.11.6
There shall be one interface for control open and one for control close operations.
The Contractor shall provide appropriate equipment to sense and latch the
remote control signal for performing the open/close control function. The BMS
digital output (DO) &analog output (AO) signal shall be as stipulated.
4.11.7
Contacts shall be rated to adequately make and break and carry continuously not
less than 5A at 250V AC or 2A at 11O V DC.Volt-free contacts for sequence of event
(SOE) and alarms shall firmly close and seat in position once activated. The
contacts shall not bounce or vibrate due to internal or external causes
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4.11.8
Required data point as per BMS requirement shall be configured in respective
controller or equipment by panel manufactures as required with necessary
hardware and software for above said serial link communication.
4.12
INDICATING LAMPS
4.12.1
Indicating lamps shall be multiple LED type. All indicating lamps shall be suitably
rated so that the indication is clearly visible from the side and front at a distance
of not less than 3 m in a room.
4.12.2
The colours of indicating lamps for red, yellow, blue phases, ACB on, off and trip
shall be red, yellow, blue, red, green and amber respectively.
4.13
LOW VOLTAGE SWITCHGEAR
4.13.1
AIR CIRCUIT BREAKERS
4.13.1.1
ACB should be mechanically robust of compact design, air break horizontal and
withdrawable type, confirming to IS/IEC 60947-2 and EN 60947-2.
4.13.1.2
Air Circuit Breaker is provided in transformer incomer, outgoing feeder,
Interconnector Bus-Section and essential/semi-essential circuit breaker as defined
in BOQ.
4.13.1.3
Manual charging as well as by 240 V AC motor with charged spring closing
mechanism complete with anti-pumping relay, discharge resistor, auxiliary
switch, etc.
4.13.1.4
240 V A.C shunt-trip coil shall be operable, within operational voltage range of
70% to 110% of rated voltage as per Clause 7.2.1.3 of IEC 60947-1.
4.13.1.5
The operating mechanism shall be trip-free.
4.13.1.6
Maximum number of circuit breaker auxiliary switches, spare auxiliary switches
to be equally divided between normally open and normally closed. At least 4
spare pairs of N.O. and N.C. volt free contacts shall be provided.
4.13.1.7
Indicating lamps for on, off, tripped on fault and trip supply healthy with all
necessary push buttons, panel wiring, bus wiring, terminals, fuses, etc.
4.13.1.8
Power and control cable terminals with undrilled gland plates for outgoing
power cables and multi-core cables.
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4.13.1.9
Electrical connection between the breaker and switchboard shall be of plug and
socket type with automatic screening shutters. An interlock to prevent
withdrawal when the breaker is closed.
4.13.1.10
Number of Poles shall be as per BOQ.
4.13.1.11
Local/auto control selecter switch shall be lockable in all positions. The
automatic control shall be defeated when the selector switch is put at local or
OFF position as per drawing and BOQ
4.13.1.12
Remote indication and alarm facilities shall be provided for Circuit-breaker open,
Circuit-breaker closed, Circuit Breaker is ready to close, Circuit-breaker tripped
on fault, and Switch position of local/remote control selector switch.
4.13.1.13
Control switch for air circuit breakers shall be as follows:
4.13.1.13.1
Air Circuit breakers shall be fitted with operative switches of the pistol
grip type. The handles of control switches for air circuit breakers shall
turn clockwise for closing and anti - clockwise for tripping.
4.13.1.13.2
The control switch shall be clearly labelled as CIRCUIT BREAKER OPEN NEUTRAL - CLOSE, with spring return to the neutral position. Mechanical
interlock shall be fitted to prevent repetitive closing without moving first
to the trip position, and shall be capable of padlocking in the neutral or
trip position.
4.13.1.14
Set of terminals wired to provide for connection to the following:
4.13.1.14.1
Automatic changeover and interlocking as shown on the drawing
4.13.1.14.2
Operation of emergency push button as per requirement or as per BOQ.
4.13.1.14.3
Signal cables wired to terminal block for remote monitoring to SCADA.
4.13.1.15
Electrical Characteristics:
4.13.1.15.1
Rated Insulation Voltage: 1000 V
4.13.1.15.2
Rated Frequency: 50 Hz
4.13.1.15.3
Rated ambient temperature: As per Clause 6.1.1 and 6.1.3 of IEC 60947
4.13.1.15.4
Utilization category: B or as per drawing or BOQ.
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4.13.1.15.5
Rated uninterrupted current: as shown on Drawings, however the contractor
must provide breaker after taking into account of the installation conditions and
derating for ambient temperature, based on selected make during preparation
of working drawings.
4.13.1.15.6
Current Ratings shall be as follows:
4.13.1.15.6.1
Rated short-time withstand current (lcw): 70/65/50 kA for 1 second
(minimum)
4.13.1.15.6.2
Rated ultimate short circuit breakigcapacity(Icu): 70/65/50 kA based on
actual fault level or as per BOQ.
4.13.1.15.6.3
Rated service short-circuit breaking capacity (Ics): 100% of Icu, and
4.13.1.15.6.4
Rated short-circuit making capacity: shall be atleast 2.1 times of ultimate
short circuit breakig capacity at 0.25 power factor or as per BOQ.
4.13.1.16
Protection
4.13.1.16.1
ACB shall have microprocessor based protection releases for type of faults with
selective over current (long time, short time & instantaneous) & earth fault
protection, measurement of electrical parameters and with communication
capability with SCADA/BMS system. Any other additional protection as
mentioned in BOQ. ACB shall have an LED/LCD display to show true RMS current
in all the three phases and highest current among these phases. The release shall
be equipped with self diagnostic feature with indication. The release shall have
zone selective interlocking and be capable for communication through Modbus
over Serial (RS 485 port) as per the requirement of design or as defined in BOQ.
The overload and short circuit characteristics should be front adjustable and
password protected.
4.13.1.16.2
The release should have an internal fault indication for faster fault diagnosis/self
diagnostic feature is required.
4.13.1.16.3
The release should have fault indications by which discrimination of fault is
possible.
4.13.1.16.4
Control relays and wiring for automatic changeover interlocking and other
breaker operation as shown on the Drawings.
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4.13.1.16.5
Fire resistant transparent covers shall be provided over ACB’s to achieve IP-54
protection and door interlock so that ACB access door shall not open if ACB is ON
otherwise it will automatically OFF if Door is opened.
4.13.1.16.6
Electrical interlock for the two incoming circuit breakers and interconnector bus section circuit breaker to prevent paralleling of different power supply sources at
any one time as shown on the Drawings
4.13.1.16.7
Following shall be provided for ACB connected to the transformer incomer:
a) Four Protection Current Transformers (three in panel, one in loose to be
mounted in transformer neutral), a Restricted Earth Fault Relay and a
Standby Earth Fault relay as specified for the interface with high voltage
switchgear.
b) Two ways inter-tripping relay shall be provided with the associated HV
feeder circuit breaker by interfacing with the Power Supply Contactor.
c) Voltage sensing relay and associated relays for automatic changeover and
interlocking operation as detailed on the Drawings.
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Interlocks and Test Operation Facilities
All ACBs shall be provided with interlocks to ensure that:
a) The ACB cannot be plugged in or isolated while it is closed,
b) The ACB cannot be closed until it is fully plugged in or completely isolated
c) The ACB cannot be closed in the service position without completing the
auxiliary circuits between the fixed and moving portions
d) With manual charged and motor charged spring mechanisms the springs
cannot be discharged until they have been fully charged and until the means
for charging has been removed or disconnected,
e) Facilities shall be provided for testing the ACB operation when in the isolated
and withdrawn positions by the normal means as in service, and
f) Where control circuits are provided and interlock circuits are broken via plugs
on withdrawal of the ACB, a minimum of one jumper lead and plug assembly
of each size and type shall be provided to facilitate testing in the withdrawn
position.
g) The neutral shall be rated for 100%
4.13.1.16.9
Safety Shutters
4.13.1.16.9.1
A set of shutters with padlocking facilities shall be provided to cover each
three phase group of stationary isolating contacts. The shutters shall be
independent and operated automatically by a positive drive from the ACB
withdrawal mechanism
4.13.1.16.9.2
In order to prevent unauthorized operation, the withdrawable air circuit
breakers shall be provided with padlock facilities to secure them in their
connected, test and isolated positions.
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4.13.2
MOULDED CASE CIRCUIT BREAKERS
4.13.2.1
MCCBs shall comply with and be type-tested to IS/IEC 60947-2 or EN 60947-2.
Each MCCB shall be of fixed or withdrawable type, as specified in the BOQ and
have all the mechanical and live parts completely enclosed in an insulated
moulded case. Withdrawable pattern circuit breakers shall be designed that their
electrical equipment can be safely disconnected from or connected to the main
circuit whilst the circuits are live.
4.13.2.2
MCCB shall be suitable for isolation as per Annexure 7.1.2 of IEC 60947-2
4.13.3
MCCBs shall meet the following requirements:
a) Number of poles: double-pole, triple-pole or four poles as specified on
theDrawings or Design or BOQ
b) Rated operational voltage: 240 / 415 V AC, as per drawing or BOQ
c) Rated insulation voltage: 660 V AC, higher voltage acceptable
d) Rated uninterrupted current (In): as shown on the Drawings or BOQ, but
after taking into account the installation conditions and temperature
deration.
e) Rated frequency: 50 Hz,
f) Rated short-circuit making capacity (Icm): shall be at least 2.1 times of
ultimate short circuit breaking capacity at 0.25 power factor,
g) Rated ultimate short-circuit breaking capacity (Icu): 65/50/35 kA (min),
h) Rated: service short-circuit breaking capacity (Ics): 65/50/35 kA Further, Ics
must be equal to 100% Icu for the selected breaker,
i) Utilization category: A or B as appropriate,
j) Degree of protection: IP 3X to IEC 60529 or EN 60529, and
k) Rated ambient temperature: As per IEC 60947-2
l) Impulse Withstand Voltage - 8KV
m) 0 - t - CO - t - Co type of Duty i.e. Ics=lcu.
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4.13.3.1
MCCB's to be provided in LV Main Switchboard shall be stored energy type
motorized and Suitable for Remote Closing by BMS.
4.13.3.2
All MCCB's should have front adjustable microprocessor based releases with
adjustment in the range of 40 - 100% for nominal overloads and adjustable
setting for short circuit faults. MCCB's for network/feeder Protection shall have
releases with earth Fault Protection features, wherever and as indicated in Bill of
quantities or drawings.
4.13.3.3
In case of 4 pole MCCB, neutral shall be defined and capable of offering
protection upto full rating with possibility of adjustment at site in the neutral
setting.
4.13.3.4
Mechanical endurance shall be as specified in latest IEC standard.
4.13.3.5
MCCB's shall have an electrical endurance operation cycles as per latest IEC
standard 60947.
4.13.3.6
All MCCB's shall be arranged for padlocking in OFF positions with lock provided.
A shunt trip coil shall be provided to facilitate automatic tripping and local
manual tripping. The manual trip device shall be fitted with the means of
padlocking. The shunt trip coil shall be suitable for operation within a voltage
range of 70% to 110% of the rated AC power supply voltage.
4.13.3.7
Electronic trip units shall comply with the requirements as specified in Appendix
F (EMC /EMI Compatibility) of IEC 60947-2 or EN 60947-2.
4.13.3.8
The trip unit shall be easily replaceable in the same MCCB without changing the
MCCB.
4.13.3.9
The time delay on overload tripping shall be inversely proportional to the over
current up to a threshold value of approximately six to seven times the rated
current at rated working temperature.
4.13.3.10
Handle position shall give positive indication of 'ON' ‘OFF’ or 'TRIPPED', thus
qualifying to disconnection as per IEC 60947-3 indicating true position of all the
contacts.
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4.13.3.11
The operating mechanism of MCCB's shall be Independent of the operating
speed of the over centre toggle and the MCCB shall be of current limiting type
and comprise of Quick make and Quick break switching. Contacts shall be nonwelding type. The operating mechanism should be trip-free and provided with
mechanical “ON", OFF" and "TRIPPED indicator. The MCCB shall be designed for
both vertical and horizontal mounting, without any adverse effect on electrical
performance.
4.13.3.12
Remote closing and tripping coil should be of continuous duty cycle.
4.13.3.13
MCCB's shall have common field fittable auxiliaries for the entire range and
above 250 A the accessories like copper spreaders and phase barriers should be
the integral part of the MCCB's.
4.13.4
MINIATURE CIRCUIT BREAKERS (MCB)
4.13.4.1
MCBs shall comply with and be type-tested to IEC 60898 or EN 60898.
4.13.4.2
MCBs shall meet the following requirements:
a) Number of poles: single-pole, double-pole, triple-pole or four-pole as specified
in the BOQ or Drawings
b) Protection against external influences: Enclosed-type,
c) Method of connection: Bolted type or clip-on type,
d) Rated operational voltage and frequency 240 / 415 V AC and 50 Hz.
e) Rated current: 6 A, 10 A, 16 A, 20 A, 25 A, 32 A, 40 A, 50 A, as shown on the
Drawings. Above 50A, MCCB as specified above must be used.
f) Range of instantaneous tripping current: MCB's shall be current limiting Type
Class 3 with range of instantaneous tripping current B, C or D type as
appropriate oras specified,
g) Rated short-circuit breaking capacity: not less than 10 kA (M3) unless
otherwise specified in BOQ
h) I2t characteristic: suitable for load and circuit being protected,
i) Degree of protection: IP-20 for MCB's
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j) Reference ambient temperature: as per IEC 60898.
k) MCB's shall have minimum power loss (Watts) per pole as per the IEC and
should be proven by published value by manufacturer.
4.13.4.3
The load handling contacts shall be silver/tungsten or proven material and the
contacts and operating mechanism shall be designed so as to give a wiping
action both at make and break. Thebreaker operating mechanism shall be of tripfree type. The breaker operating dolly shall be clearly indicated for the "ON" and
"OFF" positions. It should be of Quick make and Quick break type.
4.13.4.4
Circuit protection against overload and short-circuit conditions shall be provided
by means of thermal-magnetic device. Double-pole, triple-pole, and four pole
MCBs shall be integral units and interlocked internally so that an over current
through any pole shall trip all the poles of the MCB simultaneously. An assembly
of two or three or four single-pole units mechanically strapped together is not
acceptable.
4.13.4.5
Housing shall be heat resistant and having high impact strength. All DP, TP and
FP circuit breaker shall have a common trip bar and should be mechanically
coupled through a pin. It shall have an electrical endurance of the order of 10000
operation cycle for currentrating of up to 50A.
4.13.5
RESIDUAL CURRENT CIRCUIT BREAKER
4.13.5.1
RCCBs shall be double pole or four-pole current-operated, housed in a totally
enclosed moulded case, manufactured and tested in compliance with IEC 61008
or EN 61008.
4.13.5.2
RCCBs shall meet the following requirements:
a) Number of poles: double-pole or four-pole as specified on the Drawings,
b) Rated current (In): as shown on the Drawings,
c) Rated residual operating current: 30 mA or 100 mA or 300 mA as shown on
drawings or as per approval of the Engineer.
d) Rated voltage: 240/415 V AC,
e) Rated frequency: 50 Hz,
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f) Rated short-circuit capacity: not less than 1.5 kA unless otherwise specified in
BOQ
g) Operating characteristics in case of residual currents with DC components: as
specified,
h) Method of mounting: distribution board type,
i) Method of connection: connection shall be made with propre size of thimbles
and number ferruling for circuit identification,
j) I2t characteristic: suitable for equipment and circuit being protected
k) Degree of protection: IP 3X to IEC 60529 or EN 60529, and
l) Reference ambient temperature: As per IEC.
4.13.5.3
The tripping mechanism shall be of trip-free so that the unit cannot be held
closed against an earth fault. Tripping devices utilizing electronic amplifiers or
rectifiers are not acceptable.
4.13.5.4
Provision shall be made for testing the automatic earth - leakage tripping by an
integral test device. A device shall be fitted for prevention against reclosing after
the device has tripped on earth leakage.
4.13.6
RCBO (RESIDUAL CURRENT CIRCUIT BREAKER WITH OVER-CURRENT) PROTECTION
4.13.6.1
RCBOs shall be double pole or four-pole current-operated, housed in a totally enclosed
moulded case, manufactured and tested in compliance with IEC 61009 -1, IS 12640(part
2) 2008 and ISI marked.
4.13.6.2
RCBOs shall meet the following requirements:
a) Number of poles: double-pole or four-pole as specified on the Drawings,
b) Rated current (In): as shown on the Drawings,
c) Rated residual operating current: 30 mA or 100 mA or 300 mA as shown on drawings
or as per approval of the Engineer.
d) Rated voltage: 230/415 V AC,
e) Rated frequency: 50 Hz,
f) Rated short-circuit capacity: 10kA
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g) Operating characteristics in case of residual currents with DC components: as
specified,
h) Method of mounting: distribution board type,
i) Method of connection: connection shall be made with propre size of thimbles and
number ferruling for circuit identification,
j) I2t characteristic: suitable for equipment and circuit being protected
k) Degree of protection: IP 2X, and
l) Reference ambient temperature: As per IS 12640-1
4.13.6.3
The tripping mechanism shall be of trip-free so that the unit cannot be held closed
against an earth fault. Tripping devices utilizing electronic amplifiers or rectifiers are not
acceptable.
4.13.6.4
Provision shall be made for testing the automatic earth - leakage tripping by an integral
test device. A device shall be fitted for prevention against reclosing after the device has
tripped on earth leakage
4.13.6.5
A mechanical flag indicator on RCBO for faster identification of fault trip condition i.e.
earth leakage or over-current for faster fault diagnosis and preventive measures.
4.14
DESCRIMINATION
4.14.1
Selection of ACB, MCCB and MCB shall be of same make. Total discrimination up
to the design fault level must be available between the various elements of
switchgear (ACB, MCCB, MCB etc) selected. Supplier must provide test
certificates from acceptable, accredited and reputed laboratories or submit
published discrimination charts/tables to prove the same. In view of
Standardization and Uniformity, mixing of two series of switchgear (even from
the same manufacturer) for either MCCB or ACB will not be permitted.
4.14.2
In case higher frame sizes rating of switchgear(than those specified In the BOQ) is
required to be provided to achieve the above requirement, due to selection of a
particular make, the same shall be provided at no extra cost if other makes are
able to achieve the same with the specified frame size.
4.15
REMOTE MONITORING
The following critical status and alarms for each Electrical Panels shall be sent to
BMS for remote monitoring via volt-free contacts or serial interface over standard
protocol communication as approved but not limited to:
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a) Individual ACB/MCCB open/close status,
b) Common alarm for ACBs/MCCBs trip on fault/lock out,
c) Common alarm for any local/remote or local/auto selector switch in local
mode
d) Control supply failure,
e) ACB ready to close indication.
f) Emergency push button (EPB) operated, and
g) Busbar voltage ,current , frequency and energy parameter
h) Electrical Panels under voltage alarm and cause of tripping.
4.16
MOTOR STARTER
4.16.1
Every motor starter shall be designed to perform the following functions
efficiently and safety:
a) To start the motor without damage to the drive or driven equipment whilst
regulating the starting current to the satisfaction of the requirements of this
Specification and ensuring that at all stages of starting, the motor will develop
sufficient torque to accelerate the load.
b) To stop the motor.
c) To prevent damage to the motor due to overload, disconnection of one phase
etc..
d) To prevent damage to reduced and danger to personnel due to resumption of
the electricity supply following a failure.
e) To prevent the damage to the motor due to stalling or internal electrical or
mechanical faults by quickly disconnecting the supply.
f) To prevent damage to the motor or the starter itself due to improper, unskilled
or hesitant operation or failure to complete a starting sequence once it is
connected.
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g) To enable the motor and starter to be completely isolated from the main
supply and from all control supplies for inspection and repairs by means of
fixed type unit for each starter circuit.
4.16.2
Each motor starter assembly shall comprise MCCB/MPCB, contactors, protection
relays, electronic circuitry, control switches, lamps and instruments and
accessories as specified hereinafter. It shall include control devices for automatic
control systems. The whole unit shall be enclosed in the cubicle, from which no
access can be gained to adjoining cubicles.
4.16.3
The specified starter types are based on estimated motor ratings. The final
selection of starter shall be based on the installed motor rating. Starters and
associated over-load devices shall be selected in accordance with the run-up
time of the associated motor driven load, the maximum thermal capacity of the
motor and frequency of starting, and the duty cycle. All starters shall have
suitable protection for phase-to-phase, phase-to-neutral and phase-to-earth
faults, over-loads, and single phasing, with additional protection measures as
specified. Overload relays releases as specified shall have inverse time delay
characteristics compatible with the motor drive to which they are applied for all
protective devices the short-circuit capacity (Isc) shall be capable of withstanding
a fault current of the panel, as a minimum. The specifications of incoming and
other circuit breakers (ACB/MCCB etc.) shall be as per clause 4.13, as relevant.
4.16.4
All starters shall be in accordance with section 7.2 of IEC 60947-4-1 or EN 609474-1, and shall be adequately rated for conditions in which it shall operate.
4.16.5
All starters shall be type tested by a competent and internationally recognized
testing authority for type 2 co-ordinations in accordance with IEC 60947-4-1 or
EN 60947-4-1.
4.16.6
All contactors shall be electro-magnetic type with utilization category AC - 3 to
IEC 60947-1.
4.16.7
All starter shall be of electrically held on pattern and shall not release until the
over voltage falls below 70% of nominal.
4.16.8
Control circuits shall generally be operated on main supply derived from the
LMCP, suitably protected by MCB type 2, as specified in clause 4.13. The control
circuit shall be of self-holding and latching design.
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4.16.9
Where the control voltage is not 240V it shall be derived from transformers to BS
3535/BS 61558. Transformers shall be rated at the total control circuit load plus
a minimum of 10% spare capacity. Transformer primary windings shall be
protected by MCB's in the line connection(s) and a removable neutral link shall
be provided where the neutral is required. The supply shall be taken from
downstream of the main incoming Circuit Breaker. One end of the transformer
secondary shall be connected directly to the main earth bar. This connection
shall be upstream of the control circuit neutral link.The supply from the other
end-of the winding shall be protected by MCB.
4.16.10
The type of starters for other mechanical equipment such as plumbing, drainage,
fire services pump and other motor circuits shall be as specified in this clause
subject to rating of the motors selected during working drawing production as
per clause 4.16.3. The starters shall also comply with the requirements laid down
in the Code of Practice of electricity(Wiring) Regulations. Voltage for motors shall
be 415V 3-phase or 240V 1-phase, as required. Motors rated 0.37kW and larger
shall have a rated voltage of 415V, 3 phase, 50Hz. Motors rated smaller than
0.37 kW shall be operated at 240V 1-phase. Direct-online motor starters shall be
used for motors up to and including 3.75 kW at 415 volts, 3 phase. All motors
over this limit shall be equipped with reduced voltage starters of the star-delta
or soft starter type as indicated in BOQ.
Motor size (M)
Load
Maximum starting current in multiple
of full load current (phase of motors)
M≤ 0.37 kW
6 (single phase motor)
0.37 kW < M< 3.75 kW
6 (three phase motor)
3.75 kW ≤ M
6-7 (three phase motor)
(Tolerance in the above currents shall be of the order of ±20%)
4.16.11
The direct-on-line starters shall be provide based on condition given in Clause
4.16.10 and shall include, but not be limited to, the following:
a) MPCB as specified,
b) Triple pole air break contactor,
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c) MPCB wherever specified or required shall be provided with inbuilt
Thermal/Magnetic and single-phasing protection. MCCB, wherever specified/
required shall be of Electronic Trip Unit type with single phasing preventer
unit.
d) All Current transformers with suitable ratio, output and accuracy for motor
protection,
e) Local/off/remote control selector switch lockable in each position,
f) Set of start and stop push button,
g) Set of indicating lamps for motor running, off and tripped on fault,
h) Set of digital input (dry contacts) interface wired to terminals for wiring
connection to station building services controllers,
i) One set of terminals wired to the following:
a. Emergency stop push button, effective in all positions of the
local/remoteswitch if any.
b. Remote start/stop of the motor, effective only in the remote position
of the selector switch.
c. Hour run meter,
d. Lamp test button,
e. Any other items required to affect satisfactory motor starting and
control asspecified in this Specification, and
f. double pole contractor and motor protection unit for single phase DOL
type starter.
j) Interposing relays/contactor for remote close and remote open whenever
required.
k) Leakage Protection for DOL starters shall be provided with 25 / 40 A, 4 Pole
RCCB with sensitivity of 100/300 mA as specified.
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Based on criteria given in Clause 4.16.10 or wherever specified on the Drawings,
star-delta starters shall be provided to limit the maximum starting current within
2.5 times the rated motor full load current. The star-delta starters shall be
equipped as per direct-on-line starters specified above, with the following
additional provisions:
a) Star-delta starters shall be of the automatic type and shall comply with BS
EN60947-4-1. Triple pole air break star and delta contactors shall be
electrically interlocked so that they cannot close or be closed at the same time.
In all types ofstar-delta starters the correct phase relationship between the
star and delta connections to minimize disturbance on changeover shall be
maintained.
b) rated and adjustable solid state timer for automatic star-delta transition, and
c) Automatic changeover timers shall be adjustable from 1 second to 30 seconds.
Timers shall incorporate a fixed delay of between 20 ms between the star
contact or opening and the delta contactor closing.
d) MPCB /MCCB as specified in drawings /Schedules shall be used. MCCB shall be
as specified in clause 4.13 with the difference that the Electronic trip Units
shall be suitable for Motor Protection against Over Load (Adjustable) and Short
Circuit. For requirement of Earth fault/Earth Leakage protection, Clause
4.16.15 referred to.
4.16.13
Reversing Starters
Forward and reverse contactors will be mechanically and electrically interlocked.
Reversing starters will be in accordance with BS EN 60947 and be suitable for AC
4 utilization category.
4.16.14
Incoming Supplies
The isolation devices for assemblies with duplicated supplies shall be
interlocked(electrically and mechanically) to prevent simultaneous closure.
4.16.15
Earth Leakage/Earth Fault Protection
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For Earth Leakage /earth fault Protection for Circuits with Star-delta starters
(wherever required, based on calculations done during working drawings
Production Stage). Add- on Modules to MCCB (based on current rating of MCCB)
shall be provided with continuous adjustment from 30 mA to 10 A range with
adjustable time delay.
4.16.16
Status/Alarm
a) Indicating lamps shall be provided on each phase of the main incoming supply.
b) All assemblies incorporating automatic control systems shall be equipped with
suitable status/ alarm annunciation facilities. If these are not available directly
from the automatic control system then a separate status/alarm annunciator
shall be provided. Status/alarm enunciators shall provide indications for all
starting devices of 'ON', 'OFF'and 'TRIPPED' conditions.
c) The status/alarm annunciator equipment shall be mounted in the same
cubicle as the automatic controls. Volt-free contacts shall be provided for each
condition in each starter cubicle, which shall be wired internally to the
status/alarm annunciator, via terminals at each end.
d) The schematic diagrams as indicated in the Working Drawings shall be shown
and the operating status of all equipment shall also be indicated. Status
indicating lights shall exhibit run/stop or open/close and fault conditions. The
Contractor shall provide test buttons for the indicating lights. The layout, color,
symbols and arrangement of the mimic diagram shall be submitted to the
Engineer for review prior to manufacture.
e) Suitable interfaces shall be built into each channel to relay signals to remote
locations, by means of volt-free contacts.
f) Hours-run meters shall be fitted as specified and not be resettable.
4.16.17
Control Circuits
a) In each individual starter, the control circuit shall be provided with MCB, a
neutral link, a means of disconnection and, where specified, a disconnection
over ride switch.
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b) Neutral links shall comprise a solid copper link mounted in a white coloured
fuse base and carrier, which shall not be interchangeable with control or
power fuse carriers.
c) The control circuit supply shall be connected via an auxiliary contact on the
starter isolator.
d) Where automatic changeover systems are specified for duty/standby
operation, the control circuit for the changeover controls shall be independent
of both starters.
e) Start delay timers shall be incorporated for sequential operation of starters
where specified. The failure of one timer or starter to operate shall not prevent
operation of the remaining starters.
4.16.18
Interlocking
a) The control circuit of a dependent starter shall be wired via auxiliarymotor
cootactor in the lead starter. In the case of reduced voltage starter, the
contacts shall be on the full voltage contactor.
b) Should the lead starter be shut down either intentionally or by a fault
condition, the dependent starter shall drop out immediately.
c) A time delay shall be incorporated in the interlock circuit to delay the
operation of the dependent starter where specified. Such time delays shall be
in addition to the interlock circuits.
4.16.19
Auxiliary contacts
Two normally open and two normally closed auxiliary contacts shall be provided
for each starter as spares unless otherwise specified. These contacts shall be in
addition to contacts used for the control of the starter.
4.16.20
MPCB (MOTOR PROTECTION CIRCUIT BREAKER)
Motor circuit breakers shall comply with the general recommendations of
standard IEC 60947-1,-2 and -4-1.
1. The devices will be in utilization category A, conforming to IEC 60947-2 and
AC3 conformingto IEC 60947-4-1.
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2. Rated operational voltage of 690V AC (50/60 Hz)
3. Rated insulation voltage of 690V AC (50/60 Hz)
4. Isolation conforming to standard IEC 60947-2,
5. Rated impulse withstand voltage (Uimp) of 6 kV.
4.16.20.1
4.16.20.1.1
MPCB shall meet following requirement:Mounting:
The motor circuit breakers will be designed to be mounted vertically or
horizontally without derating Power supply will be from the top or from
the bottom.
4.16.20.1.2
Contacts:
In order to ensure maximum safety, the contacts will be isolated from
other functions such as the operating mechanism, casing, releases,
auxiliaries, etc, by high performance thermoplastic chambers.
4.16.20.1.3
Operating mechanism
The operating mechanism of the motor circuit breakers must have snap
action opening and closing with free tripping of the control devices. All the
poles will close, open, and trip simultaneously.
4.16.20.1.4
Button:
The motor circuit breakers will be actuated by a rotary operator clearly
indicating the position ON (I), OFF (O), trip
4.16.20.1.5
Isolation:
In order to ensure isolation with clearly visible breaking conforming to
standard IEC 60947-2 paragraph 7.2.7:
1. The mechanism will be designated so that the different types of
operator will only be in position (O) if the main contacts are physically
separated,
2. In position (0) the operating devices will indicate the isolated position.
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3. Isolation is enhanced by the double break of the main circuit.
4.16.20.1.6
Padlocking
Motor circuit breakers will accept a padlocking device in the "isolated"
position.
4.16.20.1.7
Trip
The motor circuit breakers will be equipped with a "PUSH TO TRIP" device
on the front enabling the correct operation of the mechanism and poles
opening to be checked.
4.16.20.1.8
Limitation, Durability
1. The motor circuit breakers will be current limiting for a mains voltage of
400 V, the maximum let-through energy (IZt) on short circuit being
extremely low.
2. The motor circuit breakers will have a high electrical and mechanism
durability of at least 5 times that required by the standard.
4.16.20.1.9
Protection functions
General recommendations:
a) The motor circuit breakers will be equipped with releases comprising a
thermal element assuring overload protection and a magnetic element
for short-circuit protection.
b) In order to ensure safety and avoid unwanted tripping, the magnetic
trip threshold (fixed) will be factory set to an average value of 12 Ir.
c) All the elements of the motor circuit breakers will be designated to
enable operation at an ambient temperature as per IEC without
derating.
d) The thermal trips will be adjustable on the the front by a rotary
selector.
e) The adjustment of the protection will be simultaneous for all poles.
4.16.21
SWITCH FUSE UNITS & DISCONNECTS/ISOLATORS (WHERE APPLICABLE)
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4.16.21.1
Switch fuse units shall have quick-make, quick-break silver plated preferably
double break contacts with operating mechanism suitable for rotary operation in
the case of cubicle mounting. All switches shall be rated according to the
equipment schedule or drawings and shall withstand the system prospective fault
current let through. Cam operated rotary switches with adequate terminal
adaptors up to 25A are acceptable but for all higher rating switch fuse units shall
be heavy-duty type.
4.16.21.2
Fuses shall be HRC cartridge type conforming to IS: 13703 - 1993 with a breaking
capacity corresponding to system fault level. Fuses shall be link type with visible
indication. Screw type fuses are not acceptable for any ratings.
4.16.21.3
All disconnects shall consist of switch units quick-make, quick-break type with
silver plated contacts. The switches shall preferably have double breaks. The
switches shall preferably have sheet steel enclosure, which in turn is mounted on
suitable angle iron frame work. In wet locations enclosures shall be IP56 rated .
Disconnects shall have a minimum breaking capacity of 5KA at 415 Volts.
4.16.21.4
Switch contacts shall be designed with arc repelling features to extinguish the arc
quickly to provide long contact life.
4.16.22
ISOLATORS
4.16.22.1
Isolators shall be fixed on wall, on self-supported galvanized angle iron frame work
as required and mounted as near to the motor as possible. Where several motors
are installed, isolators if required shall be provided at a central location on a
common frame work with prior approval at site . The Isolator shall be provided in
IP 65 enclosures from the Isolator manufacturer only.
4.16.22.2
Painting, earthing and labels shall be provided as generally indicating for MV
Switchgear and as shown on drawings.
4.17
CONTACTORS
4.17.1
Contactors shall comply with IS/IEC 60947-4-1 or EN 60947-4-1.
4.17.2
Contactors shall be electro-magnetically controlled, double air-break type.
Contactors shall be four-pole, triple-pole, double-pole or single-pole as shown on
the Drawings.
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4.17.3
The mechanical endurance of the contactors shall not be less than 3 million no.
load operating cycles.
4.17.4
Contactors shall be silver-faced.
4.17.5
The contactor should be modular in design with minimum inventory requirements
and built -in mechanically interlocked wherever required. They should be suitable
for the addition of auxiliary contacts and other electrical auxiliaries without any
compromise on the performance or the operation of the contactors. The
contactors from 4KW to 400kW shall be associated with the same 10 auxiliary
contact block range or as per BOQ.
4.17.6
The control contactors for power factor correction equipment shall be of quick
break and have a high arc resistance during switching operation. Contactors shall
be of utilization category AC-6b for this application and specifically designed for
switching directly connected capacitor banks.
4.17.7
The contactors for other applications shall have an un-interrupted rated duty and
utilization category of at least AC3 at 415V and 50 Hz. The contacts should be of
fast opening and fast closing type.
4.17.8
The making and breaking capacity values of the contactors should be as follows
(as per IEC 60947-4)
a) For AC3 duty:
 Making capacity equal to or more than 10 Ie
 Braking Capacity equal to or more than 8 Ie,
b) For AC4 duty:
 Making capacity equal to or more than 12 Ie,
 Braking Capacity equal to or more than 10 Ie,
4.17.9
The contactors should be capable of frequent switching and should operate
without derating at 60°C for AC3 applications. They should be climate proof. The
coil of the contactor should have class H insulation to support frequent switching.
Class F insulation is also acceptable with the consent of the site Engineer.
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4.17.10
The rated voltage of the contactor and the rated insulation voltage shall be 690V.
The rated Impulse voltage of the contactor should be at least 8 KV.
4.17.11
Wherever DC control is required, the contactor should have wide range (0.7 to
1.25 Uc) DC coil with built in interference suppression as required.
4.17.12
The control and power terminals should be at separate layers preferably with
colour coding (black for power and white for control). All contactors power
connection shall be finger safe (IP 2X)
4.17.13
They should be capable of being integrated into automated system (PLCs) without
any interposing components in the minimum operating conditions.
4.17.14
Contactors used with surge suppressor.
4.18
AUXILIARY SWITCHES AND CONTACTS
4.18.1
Auxiliary switches provided for indication, protection, metering, control,
interlocking supervisory purposes shall be readily accessible at the front of the
Electrical Panels. Adequate secondary contacts shall be included to enable the
auxiliary switch to be wired to the fixed portion of the equipment.
4.18.2
For each control compartment, spare auxiliary contacts with a minimum of two
NO and two NC contacts shall be provided and wired to suitably identify spare
terminals.
4.18.3
Auxiliary contacts for all applications shall be rated at 240 V AC or 110 V DC with
contact rating of at least 6 A AC or DC and operating life of atleast one million on
on-load operations at 0.4 power factor inductive load.
4.19
POWER FACTOR CORRECTION EQUIPMENT
4.19.1
Power factor correction equipment and its installation shall comply with IEC
60831/IS 13340. Each power factor correction equipment shall consist of
capacitors, switchgears, cables, cable gland, micro-processor based intelligent
power factor control relays, CTs and contactors etc.
4.19.2
Capacitor banks shall consist capacitors of variable capacity i.e. 5 kVAR, 10 kVAR,
15 kVAR, 25 kVAR or fixed type as per BOQ. Capacitor bank with total capacity as
shown on the drawings or BOQ shall be provided and connected to the designated
switchgear in the LV main switchboard to improve the overall power factor to not
less than 0.98 lagging. The system shall ensure that a leading PF does not occur.
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4.19.3
The Contractor shall ensure that the power factor correction equipment shall not
cause harmonic resonance in the LV electrical network
4.19.4
The capacitor bank shall be of floor standing type built up from static primary
capacitor units. The capacitor shall be mounted on the lower and de-tuned
inductor on the upper part of the panel so that the temperature of capacitor
environment is lower than the average temperature in the panel. In case,
ventilating fan is required to maintain the desired temperature in the capacitor
panel, the same shall switch on and off depending upon the set temperature and
only when at least one capacitor is in service. The thermostate temperature shall
be provided with step adjustment features if considered necessary as per design.
4.19.5
Each three phase capacitor unit shall be MPP self healing type with total losses
not greater than 0.5 W/kvar. The primary capacitor unit shall comply with the
requirement of IEC 60871-1 or BS 1650.
4.19.6
The capacitor unitshall be usable for indoor application with
overloads as below:
permissible

Voltage overloads shall be 10% for continuous operation and 15% for 30
minutes in a 24 hours cycle

Current overloads shall be 15 % for continuous operations and 50% for six
hours in a 24 hours cycle.

Over load of 35% continuously and 45%for six hours in a 24 hours cycle.
4.19.7
All capacitors involved shall be disconnected instantaneously, and reconnected
step by step at intervals after the supply is restored.
4.19.8
Each capacitor bank shall be fitted with an automatic discharge assembly which
shall discharge the entire capacitor bank from the peak alternating voltage to a
voltage level not exceeding 50 V measured at the capacitor bank terminals one
minute after disconnection from the supply.
4.19.9
The automatic power factor control relay (APFCR) shall be a microprocessor based
static unit with output relays equal to the no. of capacitor steps. Minimum no. of
relays shall be six/eight (6/8) or as specified in BOQ. The switching ON and OFF of
the capacitor unit shall be done in a sequence so that even wear takes place on
the contactors and relays over one week of operation.
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4.19.10
The APFC relay shall be intelligent to ensure balancing of duty cycle of the
capacitors.
4.19.11
APFC relays shall provide all necessary function of relay, controls, protection,
annunciation and condition monitoring. A no-volt and single phasing protection
shall be provided.
4.19.12
Local/off/auto selector switch and visual indication of energized capacitor with
red lamps, etc shall be provided.
4.19.13
Type tests for the equipment shall include operating voltage, temperature cycling
and repeated switching as per IEC 60831-2
4.19.14
Overcurrent shall be 1.8 x In.
4.19.15
Peak inrush current withstand capacity shall be 250 x In
4.20
DETUNED FILTER
4.20.1
Detuned harmonic filter reactors shall be used as per BOQ along with power
capacitors to mitigate harmonics amplification and to avoid electrical resonance
in LV electrical networks.
4.20.2
The reactors hall be made of high grade copper windings, having a three phase,
iron core construction suitable for indoor use. The reactor are air cooled and the
layout shall be in accordance with IEC 60289 / IS 5553.
4.20.3
The permitted tolerance of inductance is ± 3% of rated inductance value.
4.20.4
Reactor tuning factor shall be 7 % (189 Hz) and the current rating of the reactor
shall include the effects of harmonics and other possible over-currents
4.20.5
The limit of linearity of inductance of the filter reactor is: 1.8*In with L=0.95*LN.
4.20.6
All reactors shall be fitted with a temperature sensitive micro-switch in the centre
coil (normally open) for connection to trip circuits in case of high operating
temperatures.
4.21
AUTOMATIC LOAD TRANSFER SWITCHES
4.21.1
Automatic load transfer switches shall be composed of paired ACBs or MCCBs.
ACBs and MCCBs used in Automatic Load Transfer switches shall be used as
specifiedin this specification.
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4.21.2
Paired ACBs or MCCBs (as specified above) shall be provided with motorized
mechanisms for "ON/OFF" operation.
4.21.3
Each automatic load transfer switch shall be equipped with, but not be limited
to, thefollowing:
a) Illuminated indicator for "Normal Supply On" and "Standby Supply On" to be
provided at the front cover of the compartment housing the changeover
switches.
b) Transfer mechanism to facilitate automatic/ manual changeover from the
normal source to the standby source.
c) Automatic/manual change-over selector switch shall be provided. It shall be
possible to manually operate the circuit breakers in the event of absence of
control voltage.
d) ALTS should have electrical interlocking along with mechanical interlocking
through base plate to ensure that two MCCBs shall not be ON simultaneously.
e) Interlocking facility to insure that normal breaker tripped on fault will not
cause standby breaker to close or vice versa, unless the breaker are reset
manually.
f) A test switches to simulate mains power failure and indicate the changeover
sequence to allow on load testing.
g) Auxiliary relay and contacts to facilate main power source failure for routine
testing of the automatic change-over operation.
h) 2 nos. each NO and NC volt free dry contacts shall be provided for each changeover circuit breaker unit.
i) The change-over function shall work without auxiliary power supply with fail
safe operation.
j) All indications for all operations viz. ON, OFF, TRIP.
4.21.4
The changeover system between the normal and standby sources shall be as
follows:
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a) 3 phase sensing circuits with adjustable time delay facility in the range of 0 to
15 seconds shall be provided to monitor the voltage condition of the normal
and standby source.
b) Failure of one or more phases of normal main supply or are reduction of
voltage to a value of 90% to 70% (adjustable) of nominal value shall initiate
the timing device. If the failure persist at the expiry of this present time delay,
the changeover section will be effected provided that the voltage of the
standby source reaches 90% of the nominal value.
c) Upon restoration of the normal power supply, which has been determined
stable after a time delay, the changeover switch shall automatically be
restored to the normal supply. It shall also be able to switch the load back to
the normal supply under manual control.
4.22
DISTRIBUTION BOARDS
4.22.1
Distribution boards for miniature circuit breakers shall be of sheet steel
construction with aminimum thickness of 1.6 mm, suitably braced to form a rigid
structure. Exterior cornersand edges shall be rounded to give a smooth overall
appearance. Hinged swing doors shall be fitted with gaskets and shall be easily
removable to simplify installation. DBs shall be provided with suitable size of surge
protection. DBs shall be fixed with bottom at 1200 mm from finished floors. DBs
shall be fixed properly, fitted square with the frame and with holes correctly
positioned. DBs shall be fastened to the walls with suitable grouted studs of not
less than 12-mm diameter.
4.22.2
IP ratings for distribution boards shall be IP 54(used for Lights & small power).
4.22.3
All boards shall be meggered phase to phase and to neutral using 1000/500V
megger with all switches in closed position. The megger value should not be less
than 2.5 M Ohm between phases and 1.5 M Ohm between phase and neutral.
Testing of minimum 10 kA short circuit current otherwise specified in BOQ
required.
4.22.4
Each distribution board shall be arranged for top and bottom cable entry and shall
be provided with ample cable termination plates and chambers to enable cables
to be neatly glanded with tails grouped and terminated on to appropriate internal
terminations.
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4.22.5
Distribution boards shall be wall mounted and shall, where specified, incorporate
doublepole or triple pole all insulated switches as appropriate, which shall be front
of panel operated with an "ON/OFF" indicator and capable of being padlocked in
the "OFF" position. Distribution boards shall incorporate combinations of single
pole, double pole, triple pole and four pole miniature circuit-breakers
(MCBs/MCCBs) as specified in drawings.
4.22.6
Each bank of MCB's shall be clearly identified with its appropriate phase colours
code, and the mounting framework for the banks of MCB's shall be easily
removable to simplify installation. Adequate phase barriers and shields shall be
fitted to ensure that after installation and wiring, all bare terminals and wires are
covered to prevent accidental contact with live conductors during the normal
procedure of resetting MCB's.
4.22.7
Each distribution board shall be supplied complete with as built drawing /chart,
preferably mounted within the front door. This chart shall be permanently and
legibly filled in as circuits are completed, including the circuit description, the MCB
rating and theidentification of upstream source of the distribution board.
4.22.8
Each distribution board shall be clearly labeled indicating its service and all 3phase distribution boards shall be fitted with standard labels as per relevant IS.
4.22.9
In the top and bottom, of each distribution board a 32 mm clear hole in addition
to other requirements shall be provided. These spare holes shall be fitted with 32
mm stopping plugs and locknuts.
4.22.10
Spare MCB's shall be provided on the basis of one per four ways or part thereof
for every distribution board ensuring that spares are provided in numbers and
rating proportional to the numbers and ratings in the installation or as per BOQ.
4.22.11
Distribution boards shall comply with best industry practice.
4.22.12
All busbars shall be of hard drawn tinned copper having ratings as specified
complying to relevant clauses given under clause 4.1 as relevant, and shall be
electro-tinned. Neutral busbars shall be of the same cross-sectional area as the
phase busbars and shall have adequate number of terminals for all outgoing
circuits including spare ways.
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4.22.13
The configuration of the busbars, busbar supports and busbar mounting
arrangement) shall be rated at 415 V. It shall be certified to a short time
withstanding current which is not less than 10 kA for 1 sec at voltage of 415 V as
per design.
4.22.14
Multi-terminal connectors shall be provided within the distribution board for
connection of protective conductors of all outgoing circuits including spare ways.
4.22.15
Size of the DB shall be optimized precisely by proper utilization of points on
MCB. Proper utilization of points reduces the space acquired by DB as well. If the
numbers of points are few on MCB then it shall be avoided by adjusting the same
on other MCB having sufficient free points. MCB rating shall be as per the
number of points to be included. Circuit for areas other than critical rooms e.g.
SER, TER, SCR etc. shall be clubbed according to the rating of MCB. While
designing DBs, efforts shall be made in such a way that each circuit shall have not
more than 800 Watts connected load or more than 10 points, which ever is less.
However, In case of LED Points where load per point may be less, number of
points may be suitably increased.
5.
FINISHES
5.1
Sheet Steel materials used in the construction of these units should have
undergone a rigorous rust proofing process comprising of alkaline degreasing,
descaling in dilute sulphuric acid and a recognized phosphating process. The
steel work shall then receive two dip-coats of oxide filler/primer before final
painting. Castings shall be scrupulously cleaned and fettled before receiving a
similar oxide primer coat. The manufacturer is required to have 7 tank treatment
facility for this.
5.2
All exposed metal surfaces, both internal and external, shall be thoroughly
cleaned of all dust, oil, grease, scale, rust or any other contaminants and shall be
epoxy powder coated immediately at the manufacturer's factory. In case of any
doubt, the painting procedure, paint samples and process shall be approved
prior to commencement of painting.
5.3
The epoxy powder coating shall be not less than 50 micron thick and with colour
in accordance with BS 381C or BS 4800 as approved by Engineer.
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5.4
Every care shall be taken to protect the surface of the panel from damages
during transporation and installation. In case, there is any damage, the same
shall be made good by the method as approved by the site engineer which may
also include change of the panel.
6.
NAMEPLATES AND LABELS
6.1
NAMEPLATES
6.1.1
Each Electrical Panels shall have permanently attached to it in a conspicuous
position labels upon which shall be engraved or stamped with the
manufacturer's name, type and serial number, date of manufacture, designation
of each Electrical Panels, details of the loading and duty at which the item of the
Electrical Panels has been designed to operate. Such labels shall be of nonhygroscopic material.
6.2
LABELS
1. Labels shall be provided for every panel to describe the duty of or otherwise
identify every instrument, relay or item of control equipment mounted
externally and internally.
2. The designation on these labels shall be clear and shall, where applicable,
incorporate the device number along with concise descriptive wording in
English.
3. Externally fitted panel labels shall be of perspex or other approved transparent
plastic with letters and numbers rear engraved and filled with black.
4. Internally fitted panel labels shall be finished in white with engraved letters
and numbers filled with black, laminated material such as Traffolyte or rear
engraved and filled plastic may be used. Embossed materials and techniques
will not be accepted or any latest technogoly which provides same result as
mentioned above shall be applicable.
5. Labels shall be provided in conformity with the above requirements or by
other approved means wherever necessary to designate panels or panel
sections. To describe or identify circuits or circuit components, to provide
warnings or reminders of dangerous or potentially dangerous circumstances
and wherever called for elsewherein this Specification.
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6. Safety labels "Danger 415 V in both English and Hindi shall be provided on both
the front and rear of the Electrical Panels. The safety labels shall have graphic
symbols exactly as per IS standards. The design of all such signs shall be
submitted for approval. Similar labels shall be provided for other panels at
different voltages.
7. Labels shall not be less than 45 mm high. Lettering shall be of not less than 10
mm high. All labels shall be securely fixed to the panels by bolts and nuts.
8. Details of proposed inscription, including the English and Hindi wordings, and
samples of the labels shall be submitted for approval before any labels are
manufactured.
9. Circuit labels, one on the front of the panel and one on the rear of the panel
suitably engraved.
7.
FOUNDATION (IF REQUIRED) AND INSTALLATION
7.1
The location of each foundation shall be correctly set out in accordance with the
approved foundation layout drawing. Base channels shall be grouted, leveled in
cement concrete pad for switchgear and other cubicle panels, etc. with
reference to a bench mark in the building. Pedestal type panels and
superstructures shall be erected by grouting foundation bolts into the
foundation in cured holes left in foundation blocks. For concreting on existing
floors, a proper bonding surface shall be made by chipping the floor. The final
finish to the surface of the floor shall be given after all equipment has been
installed. If floor is broken for installation of equipment, it shall be restored to
original finish after completion of installation.
7.2
The concreting shall be done in accordance with the provision of Indian Standard
Code of Practice for Plain and Reinforced Concrete, IS 456-2000. Concreting IS:
383-1970 Specification for coarse and fine aggregates from natural sources for
concrete IS: 269-1989 Specification for 33 grade ordinary portland cement IS:
516-1959 Method of test for strength of concrete
7.3
Suitable grooves or niches shall be provided in the foundation block at the time
of casting to enable embodiment of earth strips without calling for chipping of
the blocks. Subsequently conduits of appropriate size shall be embedded in the
foundation blocks for cabling, in the first instance, wherever required.
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7.4
All foundations shall be cast in the presence of the Employer's representatives.
All foundation and grouted bolts shall be cured for a minimum period of 48 hrs.
7.5
Foundations shall be prepared as per manufacturers drawing, shall be leveled,
checked for accuracy and the switchboards installed. Busbar connections shall be
checked with a feeler gauge after installation. Tightness of accessible bolted bus
joints shall be checked using calibrated torque wrench. Sealing of cable and
boxes to prevent moisture entry shall be checked. Switchboard earth bars shall
be connected to the earth grid.
7.6
Fabrication drawings of all panels shall be approved by the Employer's
representative before fabrication
7.6.1
The Electrical Panels shall be installed in the locations as approved by the
Engineer. Electrical Panels shall be secured, plumbed and levelled and in true
alignment with related adjoining work,
7.6.2
The rigid galvanized U-channels to ensure effective fixing of the Electrical Panels
on the uneven floor shall be provided.
7.6.3
Anchor bolts and anchorage items shall be provided where required and field
checked to ensure proper alignment and location. Templates, layout drawings,
and supervision on Site shall be provided to ensure correct placing of anchorage
items in concrete.
7.6.4
Supporting members, fastenings, framing hangers, bracing, brackets, straps,
bolts, angles, shall be installed as required to set and rigidly connect the work.
7.6.5
Temporary bracing,gauge, or other devices shall be provided as required to
accomplish erection and to provide safety and stability until the ELECTRICAL
PANELSis in its final and approved position.
7.6.6
Erection tolerance requirements shall be controlled so as not to impair the
strength, safety, serviceability, or appearance as Approved.
7.6.7
After installations are complete, all places where the shop applied coating is
abraided, all bare steel, including bolts, nuts, washers, and welds shall be
thoroughly cleaned. Each item shall be painted with the same paint as used for
shop coating in the corresponding location.
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8.
OTHER PROVISIONS
8.1
The Electrical Panels shall be provided with all necessary cable lugs etc., fixed in
positions on mounting plates and straps, to suit the types and directions of entry
of the cables as shown on the Drawings or as specified.
8.2
Cable conductors for all circuits within the Electrical Panels shall be arranged in a
tidy manner and mechanically secured at regular intervals such that any
movement occurring to the conductors, either under normal operation
conditions (e.g. thermal expansion, vibration, etc.) or due to short circuit in any
one of the circuits, shall not cause any damage or short circuit to any healthy
bare live parts in the Electrical Panels.
8.3
Each Electrical Panels shall be supplied complete with all operating handles jigs,
etc. required for the normal charging, closing, opening, racking in and out
operations of all circuit breakers of the Electrical Panels and shall be properly
fixed in a neat manner on a board with brass hooks inside the switch room/plant
room where the Electrical Panels is installed.
8.4
Each Electrical Panels shall be provided with two rubber mats of ribbed surface,
complying to BS 921 or equivalent Indian standards, laid in front of and at the
rear of the switch board. The rubber mats shall be continuous sheets of
minimum thickness of 10 mm, each of same length as the switchboard and
minimum width of not less than 1000 mm or the width of the space between the
fronts or back of the switchboard to the adjacent wall.
8.5
Hydraulic operated handling truck suitable for handling all sizes of air circuit
breakers for the Electrical Panels shall be provided as indicated in the BOQ.
9.
SPECIAL CONDITION:
9.1
The Switchboard shall be complete with all components and accessories, which
are necessary or usual for their efficient performance and satisfactory
maintenance under the various operating and atmospheric conditions. Such parts
shall be deemed to be included within the scope of supply whether specifically
included or not in the specifications or in the tender schedules. The contractor
shall not be eligible for any extra charges for such accessories etc.
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10.
RELIABILITY, MAINTENANCE, SPARES AND LIFE
10.1
The electrical panel shall be designed for reliable and safe working. It shall be
designed for a maintenance free secure service life of switchboards, subassemblies and components for at least 30 years.
10.2
The manufacturer shall submit the list of spares which are required to be replaced
as a must change item along with interval.
11.
MATERIAL AND MANUFACTURING:
11.1
All similar items of the Electrical Panels and their component interchangeable.
Spare parts shall be manufactured originals and shall fit all similar items of the
Electrical Panels. Where machining may be needed before fitting renewable parts,
the machining fits and the associated tolerances shall be shown on the drawings
accompanying the instruction manuals.
11.2
All parts which are susceptible to wear or contaminated by dust shall enclosed in
dust-proof housings.
11.3
The style and finish of the workmanship shall be consistent throughout the Works.
Unless otherwise specified, Engineer shall decide the final colours for all paint
work and other finishes to be applied to the Electrical Panels.
12.
TESTING
12.1
The firm shall submit valid type test not more than 5 years old of the equipment
conducted at accredited/authorised/reputed/nominated by DMRC laboratory.
The type test shall be as per the governing specification.
12.2
DMRC will carry out Routine and factory acceptance tests as prescribed in the
specification with following additional test
12.3
In case of Distribution Boards type test is not essential, however test of short
circuit capacity must be submitted.
12.4
The manufacturer shall not change the Bill of Material used in the manufacturing
of samples used for Type testing. In case the bill of material is changed then
Engineer-in-charge may ask for the repetition of those type test which he
considers relevant.
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13.
Draft-2
TRAINING
The contractor shall provide the following details
 Every marshalling box and PLC compartment of the Electrical Panels shall be
provided with a wiring diagram suitably treated to prevent deterioration from
dirt or age. The diagrams shall be drawn as if viewed from the point of access
to the enclosure, and shall be securely fastened to the inside of the access
door of that compartment.
 Bound booklet consisting of the details of the equipment
 Operating manual
 Warranty/DLP
 Purchase specification of maintenance spares
 List of staff trained
 Details of service centre
14.
INDICATIVE LIST OF ITEMS TO BE INCLUDED IN FAT PLAN FOR
ELECTIRCAL PANELS
(This list is an indicative List for the inspectors to be conducted during FAT of Power Panels.
However, the detailed FAT plan needs to be developed for the specific Panel based on approved
GADs and Contract Specifications and as per the tests defined in Clause – 11 of IEC 61439 -1
(Routine Verification)/as per the relevant Standards as applicable.)
S. No
Description
Type of Check
Remarks
GENERAL
A
All items/components (switchgears, cables,
Visual Check &
wires, meters, relays etc.) used are as per the
Certification
Approved Makes, Vendors and ratings.
before Call
Obtain
letter
confirmation
B
Obtain the Factory Test reports of
from Panel
Verify
Incoming/Raw Material
Manufacturer
C
Obtain the Internal Test
for each Panel
reports/Manufacturer Test Report of Internal
duly verified
Review
Quality Tests done on Panel offered for
by the Main
Inspection as per ISO 9001.
Contractor.
D
Confirmation from Panel Manufacturer that
Penel has been manufactured strictly as per
For record
approved GADs.
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SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
E
List of tools required for Inspection and copy
of their Calibration Certificates from
independent Labs/Authorities.
Note:
All the above are to be made part of this FAT
report
Panel must be of Modular construction as
per PS. The Inspection team shall carry the
approved GAD, approved Bill of materials,
Contract Specification, relevant standards,
copy of Approvals and approved FAT Plan
from the office before proceeding for the
FAT inspection to the factory promises.
Physical/Dimensional Checks(as per approved GADs).
1
Check the Length, Breadth and Height of the
complete Panel.
2
Check dimensions of each Sections and
Cubicles.
3
Check Number and dimensions of Space for
future additions as per Specifications & Bod.
4
Check dimensions of the Doors/back Panels,
etc. (Note: Back Panel sections should not
be too bulky to handle by one individual.
May be taken care during GAD and checked
during FAT).
5
Check height/dimensions of all front
Mounting Accessories (such as indicators.
Measuring instruments, knobs, etc.)
5.1
EPB (Emergency Push Button) at 1300 mm
where applicable.
5.2
All Relays & indicating instruments between
300 to 1800 mm
5.3
Max. Operating Height should not be more
than 1800 mm
5.4
Blank Space between the Floor of Switch
board and bottom unit (Min. 200 mm or as
per PS)
6
Check size/height of Base Frame (may be
min. 100 mm. or as per PS).
6.1
The make of the manufacturer of bought
out items is clearly displayed on the items
where possible.
61
Check for
Validity
Measurement
Measurement
Measurement
Measurement
Measurement
Measuremnt
Measurement
Measurement
Measurement
Measurement
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6.2
7
7.1
7.2
7.3
7.4
7.5
7.6
8
9
10
11
12
13
13.1
13.2
13.3
Check that all materials used in the
manufacturing of the electrical panel are fire
refardant, low smoke & zero halogen.
Verify Material and Thickness of Load
bearing and Non-Load Bearing Member of
Panel Enclosure:
Panel Structure
Bus bar Section
Cable Alley
Switchgear/feeder sections
Doors
Gland Plate
Check Quality of Sheet Metal Painting and
Color used. It should be as per the
Specification/Approved drawings.
Check for the Quality of Sheet Metal
Workmanship. There shall not be any sharp
edges, burrs, dents, etc. on the panel.
Check Number and Quality of the Door
Hinges. Ensure that doors is strongly
supported and should not have any
unwanted deflection/shakiness. When door
is closed, it is latched at adequate places with
adequate crushing of gasket on metal frame.
Check Quality of the Door handles, Locks etc.
Check interlocking of Doors, Switchgears,
incomers, outgoings and couplers as per the
design logic and drawing
Check and compare the sealing
arrangements all around the panel to ensure
intended ingress Protection is achieved and
compare with the Type test reports.
Simple Paper insertion test for IP54. Insert a
paper in the gasket and metal frame, close
the door and pull the paper. It should nto
pull out.
Check Quality of Gaskets/sealing rubber, etc.
for the Doors. The arrangement shall be such
that it is replecable during maintenance.
Check Quality of Gaskets/sealing rubber, etc.,
around the cut-outs for Measuring &
62
Certificate/Me
asruement
Visual/Measur
ement
Visual
Visual
Visual
Verify and
Visual Check
Verify and
Visual Check
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DMRC Electrical Standards & Design Wing
Draft-2
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
13.4
14
14.1
14.2
15
15.1
15.2
15.3
15.4
16
indicating instruments, Switchgears, Relays
etc.
Proper sealing of knock-outs/cut-outs/gaps
for control cabling bus bar, etc., between
different feeders/sections within the Panels.
Check the Lifting arrangements (Hooks etc.)
are provided.
Adequate Number of Lifting points/Hooks
Adequate Strength of Lifting Points/Hooks
Check proper identification markings,
numbering labeling, tags have been
provided.
For the Penel
For each incoming and Outgoing Feeders
For Measuring and indicating instruments
Danger Plates/Signages
Check for rust, any sign of initiation of
corrosion, oxidation, etc., on the support
members/nut bolts/bus bars/terminal points,
etc. Initiation is an indication of use of
defective material.
CABLE ALLEYS
17
Check for Cable Entry Arrangement (top
entry/Bottom entry) as per GADs.
18
Check for Maintenance/Working space in
Cable Alleys, etc.
19
Check for adequate Space for
accommodating Cable Loops, etc.
20
Provision for securing/clamping cables in
Cable alley for proper dressing of cables.
21
Check for Knock outs for Glanding of
different smaller sizes of Cables in
Marshalling box (to be used for BMS cables).
22
Thickness of Glanding Plates should be
minimum 5.0 mm & strong enough to take
the simultaneous load/forces of cables
glanded on to it. The Cables shall be well
supported and not exert any force on the
glanding plate
23
Proper dressing/harnessing of internal
control cables and wiring within the Panel.
63
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Visual
Visual
Visual/
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Visual/
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Visual
Visual
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Visual
DMES-E/0008
DMRC Electrical Standards & Design Wing
Draft-2
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
24
Provision of identification tags/ferrules on
the internal control cables and wiring within
the Panel.
EARTHING ARRANGEMENT
25
Check that Material of Earth Bus provided in
Panel is as per PS.
26
Check the Size of continuous Earth Bus
provided in the Panel as per IEC.
27
Check if the Earth Bus is properly supported
and connected to the outside terminals.
28
Check that proper earthing has been
provided through out the Panel and all noncurrent carrying parts are properly earthed.
29
All the Gland plates have been earthed
properly
30
All Doors and openable sections must be
earthed through flexible wires/jumpers (dual
if required as per Specs)
31
Cases of all instruments and apparatus shall
be earthed by a conductor of suitable size
(but not less than 2.5 sq. mm)
32
Check that the Frame of Switchgear is
earthed, when racked in to the Cubicie.
BUS BAR SECTION
33
Check Bus bar dimensions as per Approved
GAD (Only rectangular Busbar is permitted)
34
Neutral bus shall be of full size
35
Material of the busbar shall be as per
approved specification
36
Quality (Conductivity) of the Material of the
busbar (Copper/Almunium) shall be as per
approved specification
37
Check the quality of conducting material
used for Bus bar and the Quality of Tinning
on the Copper Bus bar.
37.1
Factory tinned Bus bars to be used. Obtain
the Factory Test certificate and attach the
report.
37.2
Tinning of Bus Bar edges after cutting/sizing
also to be checked.
64
Visual
Visual
Measurement
Visual
Visual
Visual
Visual
Visual
Visual
Measurement
Measurement
Visual/
Certificate
Certificate/
Measurement
Certificate/
Measurement/
Visual
DMES-E/0008
DMRC Electrical Standards & Design Wing
Draft-2
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
38
39
39.1
40
41
42
43
44
45
46
Check that the Bending of Bus Bars should be
on Rollers of adequate diameter to avoid
undue bending stresses
Check the fixing/mounting arrangements of
Main bus bar to ensure that there are no
undue stresses due to misalignment of fixing
arrangements. (Focus on the location where
Panel is divided in to different sections to
ensure that the Bus Bar sections match
properly).
Check the proven design of bus bar
connections of OEM & its compliance in the
manufactured product
Bus bar must be color coded for Phase
identification
Note: In case, sleeve is to be provided over
the Bus bar for color coding as per PS, then
the material of the sleeve must be as per the
relevant clauses of PS.
Check the distance between Bus bar
supports and compare with Type tested
assemblies/Approved GADs.
Bus Bar Supports should be of approved
material.
Measure minimum Electrical clearences
between the bus bars for different Phases,
Neutral and Earth.
(Main Bus as well as Tap off Bus bars)
(Minimum clearance will be between Live
parts and Earth)
Check the interconnecting / Tap - off links
between Main Bus and bus sections for
proper tightness etc. (connection with the
double split cast brass clamp is permitted)
Interconnection between Bus Bar and
Switchgear - must be high conductivity
Copper Bar and must be insulated and Colour
coded
Proper compartmentation at locations where
connecting Links enter the Switchgear
section, bus bar sections and Cable Alley
must be ensured.
65
Confirmation
& Cross-Check
Visual
Visual
Measurement
Confirmation
Measurement
Measurement
Visual
Visual
DMES-E/0008
DMRC Electrical Standards & Design Wing
Draft-2
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
(Form - 4 b, Type - 5 to be ensured, for
Underground section)
For elevated, separate compartments for
incoming and Outgoing cable terminations,
to be ensured.
47
Proper Shrouding of Bus bar joints / tap off
points to be ensured. Material to be as per
PS of the Contract.
48
Proper clearances and seggregation must be
maintained between Terminals / Tap - offs of
different feeders from Main Bus Bars.
INTERNAL WIRING, TERMINAL BLOCK
49
Check if the Wiring for all power and Control
circuit is being provided as per Approved
GAD / Specifications.
Note:- Internal Wiring in LT panels to be LSZH
/ FS as per Specs for Underground stations.
For elevated stations, internal wiring may be
ensured as per PS.
50
Termination arrangements
50.1
Terminal blocks should be of Non Hygroscopic of Melamine
50.2
At terminal points - Plain and Spring Washers
with electro - tinning to be used
50.3
Check the tightness of wiring termination
50.4
Terminal should have test probe facility
50.5
All Live parts of Terminal blocks must be fully
shrouded
50.6
Spare Capacity of Terminals
50.7
Cable terminations should be with lugs of
adequate size and with proper crimping
50.8
No more than two wire to be connected to
the Terminal
50.9
Terminals should have identification Labels.
50.1
All cables should have identification ferrules
50.11
Check if the adequate size of the cables /
wires is being used for the control wiring
50.11
All the internal wiring shall be properly
dressed and randomly check the tracebility
of the wires from the wiring diagram
50.12
Check Provision of Protection for Control
wiring as approved
66
Visual
Measurement
Verify Material
Test Certificate
Verify Material
Visual
Visual
Visual
Visual
Visual
Visual
Visual
Visual
Visual
Measurement
Visual
Visual
DMRC Electrical Standards & Design Wing
DMES-E/0008
Draft-2
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
MARSHALLING BOX for BMS (if applicable)
51.1
Marshalling Box / Separate chamber for the
BMS connection is provided as per the
Visual
Approved GAD
51.2
Check the BMS points have been provided as
Visual
per the approved I/O schedule
51.3
Provision of Softlinks points for the control
Visual
shall be checked
51.4
All the terminals for the BMS shall be
properly secured and identification mark
Visual
along with the voltage level shall be provided
51.5
Randomly check voltage level at the BMS
points for any leakage voltage etc (at
Measurement
Potential free contacts)
51.6
No power wiring / cable should pass through
Visual
marshelling box
SWITICHGEARS, PROTECTIONS, INDICATIONS, ANNUNICATIONS AND MEASURING
INSTRUMENTS
52
Detailed Check list for these items of the
Factory Test
Panel may be prepared based on the GADs /
Certificates and
Contract Specifications
Test during FAT
53
54
55
56
57
Test Certificates / Calibration Certificates for
Measuring instruments to be ensured
Check Surge Arresters (if applicable) have
been provided
Separate CTs for Measurement and
Protection of relevant Class and Burden as
per PS to be ensured
Check Control Logics, Interlocks and
Protections Schemes in detail as per the
approved plan / arrangement.
Check the working of ALTS & Controls
provided for safe operation.
MISCELLANEOUS
67
Factory Test
Certificates
Visual &
Manufacturer's
Test Reports
Visual &
Manufacturer's
Test Reports
Visual,
Simulation,
Primary &
Secondary
Injection etc
Visual,
Simulation,
Primary &
Secondary
Injection etc
DMES-E/0008
DMRC Electrical Standards & Design Wing
Draft-2
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
58
59
60
61
62
63
64
65
66
APFC PANEL
67
68
69
70
71
72
Check the lights, sockets, anti condensation
heaters and air circulation means provided in
the Panels as per GADs.
All the Control and power wiring must per
properly segregated.
Padlocks and interlock provision and
Functions to be checked for the safety for
each.
Check for extendability of the Panels
(including Bus Bars) on either side.
Check provision of entry for Fire Trace Tube
and internally with in the various cubicles
and adequate sealing arrangements.
Ensure that there are No Joints in the cables
used
The tests defined in Clause - 11 of IEC 61439 1 (Routine Verification)/as per the relevant
Standards as applicable are also to be
performed for which separate Test sheet
may be prepared.
The make of the manufacturers of bought
out items is clearly displayed on the items
where posible.
Check that all materials used in the
manufacturing of the electrical panel are fire
refardant, low smoke & zero halogen.
Ensure that material/equipment of only one
make is used in the entire Electrical Panel
assembly.
Check the make, rating and specification of
capacitors used.
Check the functioning of APFEC relay as
defined in the operating manual of the relay.
Check the installation of capacitor & inductor
as per the form & specification.
Check the working of cooling fans only when
temperature goes above set value and
atleast one capacitor in service.
Check the sizing of the filter used to ascertain
the cleaning frequency for continuous
working of cooling fan.
68
Visual
Visual
Visual
Visual
DMRC Electrical Standards & Design Wing
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
15.
S. No.
DATA SHEET -
Description
Unit
Values
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
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DMES-E/0008
Draft-2
DMRC Electrical Standards & Design Wing
SPECIFICATIONS FOR LOW VOLTAGE ELECTRICAL PANELS
DMES-E/0008
Draft-2
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Length marking: Length shall be marked with number at one meter intervals on the sheath.
*Bidder to furnish the data
70