RaySol Design Guide - Applied Products TPG

RaySol Design Guide - Applied Products TPG
R
RaySol
System
D E S I G N G U I D E
RaySol System
Design Guide
RaySol System
Design Guide
Table Of Contents
1. Overview
1.1
Introduction
1
1.2
How to Use This Guide
1
1.3
System Description
2
2. Heat-Loss Replacement
3. Concrete Floor Warming
4. Tile and Marble Floor Warming
5. Freezer Frost Heave Prevention
6. Condensed Specification Guide
7. Appendix A
1.4
Codes and Approvals
2
1.5
Warranty
2
2.1
Application
3
2.2
Heating Cable and Components
3
2.3
Design Assumptions
3
2.4
Design: Determining Heating Cable Spacing
4
2.5
Layout: Laying Out Heating Cable and Components
5
2.6
Electrical Design: Selecting and Sizing Electrical Parameters
7
2.7
Example
8
3.1
Application
9
3.2
Heating Cable and Components
9
3.3
Design Assumptions
9
3.4
Design: Determining Heating Cable Spacing
10
3.5
Layout: Laying Out Heating Cable and Components
11
3.6
Electrical Design: Selecting and Sizing Electrical Parameters
13
3.7
Example
15
4.1
Application
17
4.2
Heating Cable and Components
17
4.3
Design Assumptions
18
4.4
Design: Determining Heating Cable Spacing
18
4.5
Layout: Laying Out Heating Cable and Components
19
4.6
Electrical Design: Selecting and Sizing Electrical Parameters
21
4.7
Example
22
5.1
Application
23
5.2
Heating Cable and Components
24
5.3
Design Assumptions
24
5.4
Design: Determining Heating Cable Spacing
24
5.5
Layout: Laying Out Heating Cable and Components
25
5.6
Electrical Design: Selecting and Sizing Electrical Parameters
28
5.7
Example
29
6.1
Floor Warming and Heat Loss Replacement
31
6.2
Tile and Marble Floor Warming
32
6.3
Freezer Frost Heave Prevention
33
7.1
Warranty; Suitability
35
RaySol System
Design Guide
RaySol System
Design Guide
1. Overview
1.1
The RaySol system is designed for four distinct types of applications:
• Heat-loss replacement for concrete floors
• Concrete floor warming
• Tile and marble floor warming
• Freezer frost heave prevention
Introduction
This design guide presents Raychem’s recommendations for designing a
RaySol system for each of these applications. Following the recommendations
will result in a reliable, energy-efficient system.
For information regarding other heating and heat-tracing applications, contact
your Raychem representative.
1.2
How to Use This Guide
Table 1.1 on the next page summarizes each type of application and indicates which
section in this guide contains the design recommendations for that application.
When using the RaySol System Design Guide, follow these steps:
Step 1. Define the application.
Step 2. Turn to the appropriate section for that application (refer to Table 1.1
on the next page).
Step 3. Select the spacing of the RaySol heating cable.
Step 4. Determine the heating cable and component layout.
Step 5. Design the electrical system.
If, after reading this design guide, you still have questions concerning the
design of a RaySol system, contact your Raychem representative. For instructions on installing a RaySol system, be sure to read and follow the RaySol
Installation Manual (H54693).
WARNING: RaySol heating cables and associated system components
are electrical devices that must be designed and installed properly to
ensure proper operation and to prevent shock or fire. Follow all design,
installation, assembly, and test instructions. Warnings are highlighted
with
in this design guide.
1
RaySol System
Design Guide
1. Overview
Table 1.1. Application Summary and Section Selection
Application
Heat-loss replacement Concrete
for concrete floors
floor warming
Tile and marble
floor warming
Freezer frost
heave prevention
Uses
Replace heat in
concrete floors
built over:
• garages
• loading docks
• arcades
• other cold spaces
Warm concrete
floors in:
• bathrooms
• foyers
• schools
• gymnasiums
Warm tile and
marble floors in:
• bathrooms
• foyers
Prevent heaving
in soils under:
• freezers
• refrigerated
warehouses
• cold rooms
Placed in conduit
embedded in concrete floors, or attached to the bottom
of concrete floors
Placed in conduit
embedded in concrete floors, or attached to the bottom
of concrete floors
Embedded in
mortar under tile
or marble
Placed in conduit
buried in soil or in
the subflooring under
the freezer floor
Floor design temperature
70°F (min.)
80°F (min.)
80°F (min.)
N/A
Typical heating cable spacing
18" to 42"
5" to 12"
7" to 9"
30" to 96"
Design guide section
Section 2
Section 3
Section 4
Section 5
Installation
1.3
System Description
1.4 Codes and Approvals
The RaySol system consists of:
• RaySol 1 or RaySol 2 heating cable (RaySol 1 for 110-volt to 120-volt
applications; RaySol 2 for 208-volt to 277-volt applications)
• RaySol termination components
• UL Listed or CSA Certified junction box (not supplied by Raychem)
• Ground-fault protection device (TraceGuard 277™ GFPD supplied by
Raychem)
• Optional automatic controls (not supplied by Raychem)
Paragraphs 424–44 and 424–45 of the 1993 National Electrical Code govern
the installation of RaySol heating cable for concrete and mortar floors. All
designs must also comply with all applicable local codes and standards.
RaySol heating cable shall be applied only to fire-resistant materials, and shall
not be installed in ceilings or walls.
RaySol is UL Listed as a Radiant Heating Cable for installation in mortar; in
conduit embedded in concrete, sand, or soil; or for surface mounting to the bottom of concrete floors.
RaySol is CSA Certified for use in conduit embedded in concrete floor and
directly embedded in mortar.
1.5 Warranty
The instructions in this manual and in the product packages, as well as all relevant local and national codes, must be followed. The Raychem warranty does
not apply in the event of damage caused by accident, misuse, neglect, alteration, or improper installation, repair, or testing. See the Raychem warranty
(Appendix A) for details.
Now turn to the appropriate section in this design guide as indicated in Table 1.1.
2
RaySol System
Design Guide
2. Heat-Loss Replacement
2.1
This section presents design recommendations for a RaySol heat-loss replacement system for concrete floors built over garages, loading docks, arcades, or
other cold spaces.
Application
The design goal is to prevent the floor over a cold space from cooling below
room temperature. The RaySol system achieves this by replacing the heat normally lost through the floor insulation over a cold space.
The heating cable either is attached directly to the bottom of the concrete floor
or is installed in conduit that is embedded in the concrete floor.
This section covers the most typical concrete-floor heat-loss-replacement applications. For other applications, refer to Table 1.1 in Section 1. For applications
not covered in this design guide, contact your Raychem representative for
design assistance.
2.2
Heating Cable and Components
Table 2.1 lists the cables and components that are used for concrete-floor heatloss-replacement applications.
Table 2.1. Heating Cables and Components
2.3
Design Assumptions
Description
Catalog number
Heating cable:
110–120 V
208–277 V
RaySol 1
RaySol 2
Power connection and end seal:
For cable attached to bottom of floor
For cable installed in conduit
FTC-P
FTC-XC
End seal
FTC-E
Splice:
For cable attached to bottom of
floor or for intermediate pull boxes
GMK-S or FTC-HST
The information and recommendations in this section are based on the following
design assumptions:
• The floor to be heated is indoors where the room temperature above the floor
is approximately 70°F.
• The bottom of the floor is insulated.
• The heating cable is attached to the bottom of, or installed in conduit embedded in, a standard concrete floor.
If any of these design assumptions do not apply to your application, contact
your Raychem representative for design assistance.
3
RaySol System
Design Guide
2. Heat-Loss Replacement
2.4
Determine Installation Method
The heating cable may be installed in one of two ways: fixed to the bottom of
the floor (Figure 2.1) or installed inside electrical conduit that is buried in the
floor (Figure 2.2). Attaching the heating cable directly to the bottom of the concrete floor (Figure 2.1) is the preferred method. If the bottom of the concrete
floor is not accessible, the RaySol heating cable should be installed in a
UL Listed or CSA Certified electrical conduit embedded in the concrete.
Design: Determining Heating
Cable Spacing
Concrete
Concrete
Insulation
Insulation
Figure 2.1. Heating cable attached
to the bottom of the floor.
Figure 2.2. Heating cable inside electrical
conduit embedded in the floor.
Determine Design Minimum Ambient Temperature
The design minimum ambient temperature is the lowest temperature expected
below the floor insulation.
This can be determined by using the ASHRAE 97 1/2% Winter Dry-Bulb Design
Temperature. Alternatively, if other reliable sources of information are available,
they can be used at the designer’s discretion.
Design minimum ambient temperature (°F)
Record Insulation R-Value
The insulation R-value is the thermal resistance of the floor’s insulation. Normally
the R-value will be printed on the insulation material. However, if that is not the
case, you can calculate it by dividing the insulation thickness (in inches) by the
insulation thermal conductivity.
Insulation R-value (h-ft 2/Btu)
Determine Heating Cable Spacing
Use the design minimum ambient temperature and the floor insulation R-value
to select a value from Table 2.2 on the next page. If your calculated R-value or
design minimum ambient temperature does not match the values in Table 2.2,
use the values that give the closer heating cable spacing.
If the concrete floor is placed directly on grade, install the cable on 30-inch
centers.
4
RaySol System
Design Guide
2. Heat-Loss Replacement
If the space below the floor is maintained at 50°F to 70°F, insulate the floor to
R-10 minimum and select a heating cable spacing from the 50°F row in Table 2.2.
Table 2.2. Heating Cable Spacing (in inches)
Floor insulation R-Value (h-ft2/Btu)
Lowest temperature
below floor
R-10
R-20
R-30
R-40
50°F
30
36
36
36
30°F
24
30
36
36
10°F
21
30
30
36
-10°F
18
24
30
36
-30°F
15
24
30
36
Cable spacing (inches)
2.5
Layout: Laying Out Heating
Cable and Components
Prepare Scale Drawing
In preparation for laying out each heating cable circuit, draw to scale the floor
area to be heated. Carefully note the limits of the area to be heated. Show all
concrete joints on the drawing and note the location and size of obstacles, such
as floor drains, pipe penetrations, conduit runs, columns, and fixtures.
Estimate Number of Circuits
For heating cable attached to the bottom of the floor, use the procedure that
follows. For heating cable in conduit, refer to Section 5.5 on page 25.
The length of heating cable and the number of heating cable circuits can be
estimated before a detailed layout is done if the heating cable spacing, total
heated area, and the available branch circuit breaker rating are known.
Estimate the total heating cable length as follows:
ft2 of heated floor x 12
allowComponent
Est. heating
=
+ End
ances (ft) + allowances (ft)
cable length (ft)
Heating cable spacing (in.)
The end allowance (usually 48 inches per end) is the length of heating cable
installed in protective conduit between the heated floor and the power connection junction box. The component allowance (usually 24 inches per end) is the
length of heating cable inside the power connection junction box.
Estimated heating cable length (feet)
Based on the rating of the circuit breaker and voltage, determine the maximum
length of heating cable allowed per circuit breaker from Table 2.3.
Table 2.3. Maximum Circuit Length in Feet (40°F Start-up)*
Cable operating voltage
Circuit breaker rating
120 V
208 V
220 V
240 V
277 V
30 amps
240
410
410
425
430
20 amps
160
275
275
280
290
15 amps
120
205
205
210
215
*For start-up temperatures less than 40°F, contact your Raychem representative.
Maximum circuit length (feet)
5
RaySol System
Design Guide
2. Heat-Loss Replacement
Calculate the estimated number of circuits as follows:
Estimated number
Total cable length
=
of circuits
Maximum circuit length
Round the number of circuits to the next larger whole number.
Estimated number of circuits
Locate Junction Boxes
The heating cable connects to the branch circuit wiring in a junction box by means
of a power connection and end seal—either a RaySol FTC-P for cable attached to
the bottom of the floor or a RaySol FTC-XC for cable placed in conduit.
The junction boxes may be distributed around the area to be heated, or collected
at a single location. In many applications the heating cable can be laid out so that
all power connections and end seals can be grouped in a common area without
using extra heating cable. If this can be done, select the common junction box
location to minimize the electrical conduit and wire needed to reach the branch
circuit breakers. Refer to Figure 2.3 for examples of typical layouts of cable
attached to the bottom of concrete floors.
12" typ.
24" typ.
12" typ.
24" typ.
12" typ.
24" typ.
80'
40'
A
40'
B
40'
C
Figure 2.3. Typical layouts for heating cable attached to the bottom of concrete floors
(for typical conduit layout, refer to Figures 5.2 and 5.3 on page 27)
Lay Out Heating Cable
After determining the approximate total length of heating cable, the number of
circuits, and the junction box location, do a trial layout. In making the trial layout,
follow these recommendations:
• Start and end each circuit in a junction box. The power connection and end
seal may be located in the same box or in different boxes.
• Do not design more than one run of heating cable per conduit.
• Arrange the heating cable in a serpentine pattern to uniformly cover the area
to be heated.
• Maintain the design heating cable spacing within 1 inch.
• Do not extend the heating cable beyond the room or area in which it originates.
• Do not cross expansion, crack control, or other joints.
6
RaySol System
Design Guide
2. Heat-Loss Replacement
• Do not route the heating cable closer than 4 inches to the edge of the concrete floor, drains, anchors, or other material in the concrete.
• Do not exceed the maximum length of heating cable allowed on a branch circuit breaker as determined from Table 2.3. The maximum length includes the
heating cable covering the floor as well as the heating cable included in the
junction box and protective conduit.
• If the heating cable is to be installed in conduit, the maximum length of heating cable that can be pulled is 450 feet. The maximum total degree of conduit
turn is 360 degrees.
• Do not install RaySol heating cable in ceilings or walls.
Record Circuit Information
Reconstruct the trial circuit layout until the design meets all of the previous recommendations. Record the total length of heating cable used on each circuit.
Assign each circuit to a circuit breaker in a specific panel board and record each
circuit length.
Actual cable length per circuit (feet)
2.6
Electrical Design: Selecting and
Sizing Electrical Parameters
Select Cable
Select the RaySol heating cable that matches your operating voltage:
• RaySol 1: 110–120 volts
• RaySol 2: 208–277 volts
Cable
Record Branch Circuit Breaker Rating
Record the circuit breaker rating to be used.
Use ground-fault protection devices (GFPDs) for all RaySol applications.
Ground-fault protection devices with a 30-mA trip level are available from
Westinghouse (GFEPD) and Square-D (QO-EPD). If operating at 277 volts, use
a Raychem TraceGuard 277™ GFPD.
WARNING: To minimize the danger of fire from sustained electrical arcing
if the heating cable is damaged or improperly installed, use a ground-fault
protection device (GFPD) with a nominal 30-milliampere (mA) trip level.
Arcing may not be stopped by conventional circuit breakers.
Circuit breaker rating (amps)
Select Maximum Length of Heating Cable per Branch Circuit
Based on the layout and using the circuit breaker rating, select from Table 2.3
the maximum length of heating cable allowed on a branch circuit.
Maximum circuit length (feet)
Select Junction Box
For the heating cable power connection and end seal, select a UL Listed or CSA
Certified junction box that is suitable for the location. Use a box with a minimum
internal volume of 16 cubic inches if the box is metallic and 19 cubic inches if the
box is not metallic.
The junction box containing the RaySol power connection and end seal must be
accessible. According to the National Electrical Code, “accessible” is defined as
1) capable of being removed or exposed without damaging the building structure or finish, or 2) not permanently closed in by the structure or finish of the
building. Refer to Article 370-19 of the National Electrical Code for restrictions
on junction box location.
7
RaySol System
Design Guide
2. Heat-Loss Replacement
Size Transformer
Calculate the total transformer load as:
Total cable length (ft)
Transformer = 0.8 x Circuit breaker x
x Voltage
load (W)
rating (A)
Maximum circuit length (ft)
Transformer load (watts)
Select Controls (optional)
For situations where controls are desired, there are three types of controls that
may be used with heat-loss-replacement systems:
• Manual control
• Ambient temperature control
• Floor temperature sensing control
Manual control
With manual control, the heating system is switched on and off using either a manual switch or a circuit breaker. The system can also be energized continuously.
Ambient temperature control
With ambient temperature control, the heat-loss-replacement system is controlled by an ambient-air-temperature-sensing thermostat, such as Raychem
AMC-1A. When the outside air temperature drops below a preset temperature,
usually 40°F, the heating cable is energized.
Floor temperature sensing control
By utilizing a thermostat with a sensing bulb embedded in the floor, the temperature of the floor can be controlled directly.
2.7
Example
This example is based on Figure 2.3-A on page 6. It represents a heat-loss
replacement application where the minimum ambient temperature below the
floor is -10°F and the floor is insulated to R-20. The heating cable will be
attached to the bottom surface of the floor.
Twenty-four-inch heating cable spacing was selected from Table 2.2 on page 5.
Twenty-four inches of heating cable per end was allowed for the component
allowance and 48 inches per end for the end allowance.
The estimated heating cable length is calculated as follows (based on the formula on page 5):
Estimated heating
40 ft x 80 ft x 12
=
+ 40 ft + 20 ft = 1660 ft
cable length
24 in
The initial estimate for the number of circuits was four. However, after the layout
was finalized, the actual length of heating cable used was 1665 feet in five circuits,
making the length of cable per circuit 333 feet.
The circuit breaker rating is 30 amps, the voltage is 277 Vac, and the maximum
circuit length from Table 2.3 is 430 feet.
The transformer load per circuit is calculated as follows (based on the formula
on this page):
Transformer load = 0.8 x 30 A x
8
333 ft
x 277 Vac = 5148 W
430 ft
RaySol System
Design Guide
3. Concrete Floor Warming
3.1
This section presents design recommendations for a concrete floor warming system using RaySol heating cables for bathrooms, foyers, schools, or gymnasiums.
Application
The design goal is to raise the floor temperature to 80°F or above so it is comfortable to walk on the floor in bare feet.
The heating cable either is attached directly to the bottom of the concrete floor
or is installed inside conduit that is embedded in the concrete floor.
This section covers the most typical concrete floor warming applications. For other
applications, refer to Table 1.1 in Section 1. For applications not covered in this
design guide, contact your Raychem representative for design assistance.
3.2
Heating Cable and Components
Table 3.1 lists the cables and components that are used for concrete floor
warming applications.
Table 3.1. Heating Cables and Components
3.3
Design Assumptions
Description
Catalog number
Heating cable:
110–120 V
208–277 V
RaySol 1
RaySol 2
Power connection and end seal:
For cable attached to bottom of floor
For cable installed in conduit
FTC-P
FTC-XC
End seal
FTC-E
Splice:
For cable attached to bottom of
floor or for intermediate pull boxes
GMK-S or FTC-HST
The information and recommendations in this section are based on the following
design assumptions:
• The floor to be heated is indoors where the room temperature above the floor
is approximately 70°F.
• The bottom of the floor is insulated.
• The heating cable is attached to the bottom of, or installed in conduit embedded
in, standard concrete floor.
If any of these design assumptions do not apply to your application, contact
your Raychem representative for design assistance.
9
RaySol System
Design Guide
3. Concrete Floor Warming
3.4
Determine Installation Method
The heating cable may be installed in one of two ways: fixed to the bottom of
the floor (Figure 3.1) or installed inside electrical conduit that is buried in the
floor (Figure 3.2). Attaching the heating cable directly to the bottom of the concrete floor (Figure 3.1) is the preferred method. If the bottom of the concrete
floor is not accessible, the RaySol heating cable should be installed in a UL
Listed or CSA Certified electrical conduit embedded in the concrete.
Design: Determining Heating
Cable Spacing
Concrete
Concrete
Insulation
Insulation
Figure 3.1. Heating cable attached
to the bottom of the floor.
Figure 3.2. Heating cable inside electrical
conduit embedded in the floor.
Since the power output of a self-regulating cable varies with the method of
installation, the heating cable spacing table (Table 3.2 on the next page) shows
a different value for each method.
Determine Design Minimum Ambient Temperature
The design minimum ambient temperature is the lowest temperature expected
below the floor insulation.
This can be determined by using the ASHRAE 97 1/2% Winter Dry-Bulb Design
Temperature. Alternatively, if other reliable sources of information are available,
they can be used at the designer’s discretion.
Design minimum ambient temperature (°F)
Record Insulation R-Value
The insulation R-value is the thermal resistance of the floor’s insulation.
Normally the R-value will be printed on the insulation material. However, if that
is not the case, you can calculate it by dividing the insulation thickness in inches
by the insulation thermal conductivity.
Insulation R-value (h-ft 2/Btu)
10
RaySol System
Design Guide
3. Concrete Floor Warming
Determine Heating Cable Spacing
Use the design minimum ambient temperature, the floor insulation R-value, and
the installation method to select the correct heating-cable spacing from Table 3.2
below. If your calculated R-value or design minimum ambient temperature does
not match the values in Table 3.2, use the values that give you the closer heating
cable spacing.
For on-grade installations use heating cable on 6-inch centers if the heating
cable is installed in conduit.
If the space below the floor is maintained at 50°F to 70°F, insulate the floor to R-10
minimum and select a heating cable spacing from the 50°F row in Table 3.2.
Table 3.2. Heating Cable Spacing (in inches)
3.5
Layout: Laying Out Heating
Cable and Components
Floor insulation R-value (h-ft2/Btu)
Lowest temperature
below floor
Installation
method
R-10
R-20
R-30
R-40
50°F
Surface
Conduit
8
6
9
6
9
6
9
6
30°F
Surface
Conduit
7
5
8
6
9
6
9
6
10°F
Surface
Conduit
7
5
8
5
9
6
9
6
-10°F
Surface
Conduit
6
4
8
5
8
5
9
6
-30°F
Surface
Conduit
6
4
7
5
8
5
8
6
Cable spacing (inches)
Prepare Scale Drawing
In preparation for laying out each heating cable circuit, draw to scale the floor
area to be heated. Carefully note the limits of the area to be heated. Show all
concrete joints on the drawing and note the location and size of obstacles, such
as floor drains, pipe penetrations, conduit runs, columns, and fixtures.
Estimate Number of Circuits
For heating cable attached to the bottom of the floor, use the procedure that follows.
For heating cable in conduit, refer to Section 5.5 on page 25.
The length of heating cable and the number of heating cable circuits can be
estimated before a detailed layout is done if the heating cable spacing, total
heated area, and the available branch circuit breaker rating are known. Estimate
the total heating cable length as follows:
Est. heating
=
cable length (ft)
ft2 of heated floor x 12
allowComponent
+ End
ances (ft) + allowances (ft)
Heating cable spacing (in)
The end allowance (usually 48 inches per end) is the length of heating cable
installed in protective conduit between the heated floor and the power connection junction box. The component allowance (usually 24 inches per end) is the
length of heating cable inside the power connection junction box.
Estimated heating cable length (feet)
11
RaySol System
Design Guide
3. Concrete Floor Warming
Based on the rating of the circuit breaker and voltage, determine the maximum
length of heating cable allowed per circuit breaker from Table 3.3.
Table 3.3. Maximum Circuit Length in Feet (40°F Start-up)*
Cable operating voltage
Circuit breaker rating
120 V
208 V
220 V
240 V
277 V
30 amps
240
410
410
425
430
20 amps
160
275
275
280
290
15 amps
120
205
205
210
215
*For start-up temperatures less than 40°F, contact your Raychem representative.
Maximum circuit length (feet)
Calculate the estimated number of circuits as follows:
Total cable length
Estimated number =
of circuits
Maximum circuit length
Round the number of circuits to the next larger whole number.
Estimated number of circuits
Locate Junction Boxes
The heating cable connects to the branch circuit wiring in a junction box using a
power connection and end seal—either a RaySol FTC-P for cable attached to
the bottom of the floor or FTC-XC for cable placed in conduit.
The junction boxes may be distributed around the area to be heated, or collected
at a single location. In many applications the heating cable can be laid out so that
all power connections and end seals can be grouped in a common area without
using extra heating cable. If this can be done, select the common junction box
location to minimize the wire needed to reach the branch circuit breakers. Refer
to figure 3.3 for examples of typical layouts of cable attached to the bottom of
concrete floors.
4" typ.
8" typ.
4" typ.
8" typ.
4" typ.
8" typ.
27'
13'
A
12
13'
B
13'
C
Figure 3.3. Typical layouts for heating cable attached to the bottom of concrete floors
(for typical conduit layout, refer to Figures 5.2 and 5.3 on page 27)
RaySol System
Design Guide
3. Concrete Floor Warming
Lay Out Heating Cable
After determining the approximate total length of heating cable, the number of
circuits, and the junction box location, do a trial layout. In making the trial layout,
follow these recommendations:
• Start and end each circuit in a junction box. The power connection and end
seal may be located in the same box or in different boxes.
• Do not design more than one run of heating cable per conduit.
• Arrange the heating cable in a serpentine pattern to cover the area to be
heated uniformly.
• Maintain the design heating cable spacing within 1 inch.
• Do not extend the heating cable beyond the room or area in which it
originates.
• Do not cross expansion, crack control, or other joints.
• Do not route the heating cable closer than 4 inches to the edge of the concrete floor, drains, anchors, or other material in the concrete.
• Do not exceed the maximum length of heating cable allowed on a branch circuit breaker as determined from Table 3.3. The maximum length includes the
heating cable covering the floor as well as the heating cable included in the
junction box and protective conduit.
• If the heating cable is to be installed in conduit, the maximum length of heating cable that can be pulled is 450 feet. The maximum total degree of conduit
turn is 360 degrees.
• Do not install RaySol heating cable in ceilings or walls.
Record Circuit Information
Reconstruct the trial circuit layout until the design meets all of the recommendations noted above. Record the total length of heating cable used on each circuit.
Assign each circuit to a circuit breaker in a specific panel board and record each
circuit length.
Actual cable length per circuit (feet)
3.6
Electrical Design: Selecting and
Sizing Electrical Parameters
Select Cable
Select the RaySol heating cable that matches your operating voltage:
• RaySol 1: 110–120 volts
• RaySol 2: 208–277 volts
Cable
Record Branch Circuit Breaker Rating
Record the circuit breaker rating to be used.
Use ground-fault protection devices (GFPDs) for all RaySol applications.
Ground-fault protection devices with a 30-mA trip level are available from
Westinghouse (GFEPD) and Square-D (QO-EPD). If operating at 277 volts, use
a Raychem TraceGuard 277 GFPD.
WARNING: To minimize the danger of fire from sustained electrical arcing
if the heating cable is damaged or improperly installed, use a ground-fault
protection device (GFPD) with a nominal 30-milliampere (mA) trip level.
Arcing may not be stopped by conventional circuit breakers.
Circuit breaker rating (amps)
13
RaySol System
Design Guide
3. Concrete Floor Warming
Select Maximum Length of Heating Cable per Branch Circuit
Based on the layout and using the circuit breaker rating, select from Table 3.3
the maximum length of heating cable allowed on a branch circuit.
Maximum circuit length (feet)
Select Junction Box
For the heating cable power connection and end seal, select a UL Listed or
CSA Certified junction box suitable for the location. Use a box with a minimum
internal volume of 16 cubic inches if the box is metallic and 19 cubic inches if
the box is not metallic.
The junction box containing the RaySol power connection and end seal must be
accessible. According to the National Electrical Code, “accessible” is defined as
1) capable of being removed or exposed without damaging the building structure or finish, or 2) not permanently closed in by the structure or finish of the
building. Refer to Article 370-19 of the National Electrical Code for restrictions
on junction box location.
Size Transformer
Calculate the total transformer load as:
Total cable length (ft)
Transformer = 0.8 x Circuit breaker x
x Voltage
load (W)
rating (A)
Maximum circuit length (ft)
Transformer load (watts)
Select Controls (optional)
For situations where controls are desired, there are three types of controls that
may be used with concrete floor warming systems:
• Manual control
• Ambient temperature control
• Floor temperature sensing control
Manual control
With a manual control, the concrete floor warming system is switched on and off
using either a manual switch or a circuit breaker. The system can also be energized continuously.
Ambient temperature control
With ambient temperature control, the concrete floor warming system is controlled by an ambient-air-temperature-sensing thermostat, such as Raychem
AMC-1A. When the outside air temperature drops below a preset temperature,
usually 40°F, the heating cable is energized. Ambient temperature control is
normally used only with systems designed for floor heat loss replacement.
Floor temperature sensing control
By utilizing a thermostat with a sensing bulb embedded in the floor, the temperature of the floor can be controlled directly.
14
RaySol System
Design Guide
3. Concrete Floor Warming
3.7 Example
This example is based on Figure 3.3-A on page 12. It represents a concrete
floor warming application where the minimum temperature below the floor is
30°F and the floor is insulated to R-20. The heating cable will be attached to
the bottom surface of the floor.
Eight-inch heating cable spacing was selected from Table 3.2 on page 11.
Twenty-four inches of heating cable per end was allowed for the component
allowance and 48 inches per end for the end allowance.
The estimated heating cable length is calculated as follows (based on the formula on page 11):
Estimated heating
13 ft x 27 ft x 12
=
+ 40 ft + 20 ft = 587 ft
cable length
8 in
The initial estimate for the number of circuits was three. However, after the layout was finalized, the actual length of heating cable used was 590 feet in five
circuits, making the length of cable per circuit 118 feet.
The circuit breaker rating is 15 amps, the voltage is 220 Vac, and the maximum
circuit length from Table 3.3 is 205 feet.
The transformer load per circuit is calculated as follows (based on the formula
on page 14):
Transformer load = 0.8 x 15 A x
118 ft
x 220 Vac = 1520 W
205 ft
15
RaySol System
Design Guide
16
RaySol System
Design Guide
4. Tile and Marble
Floor Warming
4.1
This section presents design recommendations for tile and marble floor warming
systems using RaySol 1 heating cable for bathrooms and foyers.
Application
The design goal is to raise the floor surface temperature above 80°F, making it
comfortable to walk on with bare feet.
RaySol 1 heating cable is embedded in the mortar setting bed under a tile or
marble floor. Do not install it in showers or under bath tubs.
This section covers the most typical tile and marble floor warming applications.
If your application is not covered here, please refer to Table 1.1 in section 1. For
applications not covered in this design guide, contact your Raychem representative for design assistance.
4.2
Heating Cable and Components
Table 4.1 lists the cables and components that are used in tile and marble floor
warming applications.
Table 4.1. Heating Cable and Components
Description
Catalog number
Heating cable (110–120 V)
RaySol 1
Power connection and end seal
FTC-XC
End seal
FTC-E
Splice (for intermediate pull boxes)
GMK-S or FTC-HST
17
RaySol System
Design Guide
4. Tile and Marble
Floor Warming
4.3
The information and recommendations in this section are based on the following
design assumptions:
• The floor to be heated is indoors where the room temperature above the floor
is approximately 70°F.
• The bottom of the floor is insulated or located on grade.
• The heating cable is embedded in standard-density mortar. Lightweight, dryset mortar such as Gypcrete is not considered standard.
• The minimum thickness of the mortar is 1 inch.
• The heating cable shall not be installed in shower floors.
Design Assumptions
If any of these design assumptions do not apply to your application, contact
your Raychem representative for design assistance.
Junction box
1
⁄2" Conduit
Heating cable
Mortar
Subfloor
Insulation
6"
Figure 4.1. Typical tile and marble installation
4.4
Design: Determining Heating
Cable Spacing
Determine Design Minimum Ambient Temperature
The design minimum ambient temperature is the lowest temperature expected
below the floor insulation.
This can be determined by using the ASHRAE 97 1/2% Winter Dry-Bulb Design
Temperature. Alternatively, if other reliable sources of information are available,
they can be used at the designer’s discretion.
Design minimum ambient temperature (°F)
18
RaySol System
Design Guide
4. Tile and Marble
Floor Warming
Record Insulation R-Value
The insulation R-value is the thermal resistance of the floor’s insulation.
Normally the R-value will be printed on the insulation material. However, if that
is not the case, you can calculate it by dividing the insulation thickness in inches
by the insulation thermal conductivity.
Insulation R-value (h-ft 2/Btu)
Determine Heating Cable Spacing
Use the design minimum ambient temperature and the floor insulation R-value to
select the correct heating cable spacing from Table 4.2. If your calculated R-value
or design minimum ambient temperature does not match the values in Table 4.2,
use the values that give the closer heating cable spacing.
For on-grade installations use heating cable on 9-inch centers.
If the space below the floor is maintained at more than 50°F, insulate the floor to
R-10 minimum and select a heating cable spacing from the 50°F row in Table 4.2.
Table 4.2. Heating Cable Spacing (in inches)
Floor insulation R-Value (h-ft2/Btu)
Temperature
below floor
R-10
R-20
R-30
R-40
50°F
8
9
9
9
30°F
7
8
8
8
10°F
7
7
8
8
-10°F
6
7
7
8
-30°F
6
7
7
7
Cable spacing (inches)
4.5
Layout: Laying Out Heating
Cable and Components
Prepare Scale Drawing
In preparation for laying out each heating cable circuit, draw to scale the floor
area to be heated. Note the limits of the heated area carefully. Show all concrete joints on the drawing and note the location and size of obstacles such as
floor drains, pipe penetrations, conduit runs, columns, and fixtures.
Estimate Number of Circuits
The length of heating cable and the number of heating cable circuits can be
estimated before a detailed layout is done if the heating cable spacing, total
heated area, and the available branch circuit breaker rating are known. Estimate
the total heating cable length as:
Est. heating
=
cable length (ft)
ft2 of heated floor x 12
allowComponent
+ End
ances (ft) + allowances (ft)
Heating cable spacing (in)
The end allowance (usually 48 inches per end) is the length of heating cable
installed in protective conduit between the heated floor and the power connection junction box. The component allowance (usually 24 inches per end) is the
length of heating cable inside the power connection junction box.
Estimated heating cable length (feet)
19
RaySol System
Design Guide
4. Tile and Marble
Floor Warming
Based on the rating of the circuit breaker, determine the maximum length of
heating cable allowed per circuit breaker from Table 4.3.
Table 4.3. Maximum Circuit Length in Feet (40°F Start-up)*
Circuit breaker rating
RaySol circuit length
30 amps
160
20 amps
105
15 amps
80
*For start-up temperatures less than 40°F, contact your Raychem representative.
Maximum circuit length (feet)
Calculate the estimated number of circuits as follows:
Total cable length
Estimated number =
of circuits
Maximum circuit length
Round the number of circuits to the next larger whole number.
Estimated number of circuits
Locate Junction Boxes
The heating cable connects to the branch circuit wiring in a junction box by
means of a RaySol FTC-XC power connection and end seal.
The junction boxes may be distributed around the area to be heated, or collected at a single location. In many applications the heating cable can be laid out so
that all power connections and end seals can be grouped in a common area
without using extra heating cable. If this can be done, select the common junction box location to minimize the electrical conduit and wire needed to reach the
branch circuit breakers.
Lay Out Heating Cable
After determining the approximate total length of heating cable, the number of
circuits, and the junction box location, do a trial layout. In making the trial layout
follow these recommendations:
• Start and end each circuit in a junction box. The power connection and end
seal may be located in the same box or in different boxes.
• Do not design more than one run of heating cable per conduit.
• Arrange the heating cable in a serpentine pattern to cover the area to be
heated uniformly.
• Maintain the design heating cable spacing within 1 inch.
• Do not extend the heating cable beyond the room or area in which it originates.
• Do not cross expansion, crack control, or other joints.
• Do not route the heating cable closer than 4 inches to the edge of the tile or
marble floor, drains, anchors, or other material in the setting bed.
• Do not exceed the maximum length of heating cable allowed on a branch circuit breaker as given in Table 4.3. The maximum length includes the heating
cable covering the floor as well as the heating cable included in the junction
box and protective conduit.
• Do not install RaySol heating cable in ceilings or walls.
• Do not bury splices in mortar. Splices can only be used in intermediate pull
boxes.
20
RaySol System
Design Guide
4. Tile and Marble
Floor Warming
Record Circuit Information
Reconstruct the trial circuit layout until the design meets all of the previous
recommendations. Record the total length of heating cable used on each circuit.
Assign each circuit to a circuit breaker in a specific panel board and record each
circuit length.
Actual cable length per circuit (feet)
4.6
Electrical Design: Selecting and
Sizing Electrical Parameters
Select Cable
RaySol 1 cable is suitable for operating voltages of 110 to 120 Vac.
Cable
RaySol 1
Select Branch Circuit Breaker Rating
Record the circuit breaker rating to be used.
Use ground-fault protection devices (GFPDs) for all RaySol applications.
WARNING: To minimize the danger of shock or of fire from sustained electrical arcing if the heating cable is damaged or improperly installed, use a
ground-fault protection device (GFPD) with a nominal 5-milliampere (mA)
trip level. Arcing may not be stopped by conventional circuit breakers.
Circuit breaker rating (amps)
Select Maximum Length of Heating Cable per Branch Circuit
Based on the layout and using the circuit breaker rating, select from Table 4.3
the maximum length of heating cable allowed on a branch circuit.
Maximum circuit length (feet)
Select Junction Box
For the heating cable power connection and end seal, select a UL Listed or CSA
Certified junction box that is suitable for the location. Use a box with a minimum
internal volume of 16 cubic inches if the box is metallic and 19 cubic inches if the
box is not metallic.
The junction box containing the RaySol power connection and end seal must be
accessible. According to the National Electrical Code, “accessible” is defined as
1) capable of being removed or exposed without damaging the building structure or finish, or 2) not permanently closed in by the structure or finish of the
building. Refer to Article 370-19 of the National Electrical Code for restrictions
on junction box location.
Size Transformer
Calculate the total transformer load as:
Total cable length (ft)
Transformer = 0.8 x Circuit breaker x
x Voltage
load (W)
rating (A)
Maximum circuit length (ft)
Transformer load (watts)
21
RaySol System
Design Guide
4. Tile and Marble
Floor Warming
Select Controls (optional)
The RaySol 1 heating cable has a start-up characteristic similar to that of an
incandescent lighting load. Any control used to switch the heating cable should
be suitable for incandescent loads and should have an ampacity equal to that of
the branch circuit.
Manual control
It is common for floor-warming systems to be operated 24 hours a day without
any temperature controls other than the inherent self-regulating action of the
RaySol 1 heating cable. When operated without external temperature controls
the maximum floor temperature will be between 85°F and 95°F. If the heating
cable is to be switched by a time clock, set the clock to energize the system
about two hours before the floor needs to be warm to allow time for warm-up.
Thermostatic control
By utilizing a thermostat with a sensing bulb embedded in the floor, the temperature of the floor can be controlled directly. For direct temperature control use a
thermostat with a remote sensing bulb similar to the Raychem AMC-1B. Locate
the thermostat sensing bulb at the same elevation as the heating cable and midway between adjacent runs of cable. Keep the sensing bulb as far from the
walls of the room as possible. Install the sensing bulb inside PVC conduit so
that the bulb can be removed if service is ever necessary.
4.7
Example
This example is based on a bathroom (10 feet x 10 feet) where the lowest temperature underneath the floor is 10°F and the floor is insulated to R-10. The circuit
breaker rating is 30 amps and the voltage is 120 Vac.
Seven-inch heating cable spacing was selected from Table 4.2 on page 19.
Twenty-four inches of heating cable per end was allowed for the component
allowance, and 48 inches per end for the end allowance.
The total heating cable length is calculated as follows (based on the formula on
page 19):
Estimated heating
10 ft x 10 ft x 12
=
+ 8 ft + 4 ft
cable length
7 in
= 183 ft
After the layout was finalized, the actual length of heating cable used was 190
feet in two circuits, making the length of cable per circuit 95 feet.
The circuit breaker rating is 30 amps, the voltage is 120 Vac, and the maximum
circuit length from Table 4.3 is 160 feet.
The transformer load per circuit is calculated as follows (based on the formula
on page 21):
Transformer load = 0.8 x 30 A x
22
95 ft
x 120 Vac = 1710 W
160 ft
RaySol System
Design Guide
5. Freezer Frost
Heave Prevention
5.1
This section presents design recommendations for RaySol freezer-floor frostheave-prevention systems. The heating cable is installed inside electrical conduit embedded in concrete, sand, or soil.
Application
Subfreezing temperatures inside cold rooms and freezers cause heat to be lost
from the soil under the floor, even when it is well insulated. As the soil freezes,
capillary action draws water into the frozen areas where the water forms a concentrated ice mass. As the ice mass grows, it heaves the freezer floor and
columns, causing damage.
Concrete
Insulation
Conduit
Subfloor
Heating cable
Soil
Figure 5.1. Typical freezer frost prevention installation
The electrical conduit carrying the RaySol heating cable may be installed in the
subfloor under the freezer-floor insulation, as illustrated in Figure 5.1. The subfloor layer may be a reinforced concrete slab, a concrete mud slab, a bed of
compacted sand, or simply compacted fill. The conduit spacing will vary from
96 inches to 30 inches, depending on the design conditions.
This section covers the most typical freezer-frost-heave-prevention applications.
For other applications, refer to Table 1.1 in Section 1. For applications not covered in this design guide, contact your Raychem representative for design
assistance.
23
RaySol System
Design Guide
5. Freezer Frost
Heave Prevention
5.2
Table 5.1 lists the cables and components that are used for freezer-frost-heaveprevention applications.
Heating Cable and Components
Table 5.1. Heating Cables and Components
5.3
Design Assumptions
Description
Catalog number
Heating cable:
110–120 V
208–277 V
RaySol 1
RaySol 2
Power connection and end seal
FTC-XC
End seal
FTC-E
Splice (for intermediate pull boxes)
GMK-S or FTC-HST
The information and recommendations in this section are based on the following
design assumptions:
• Any size freezer or cold room operating below 32°F will experience frost
heaving.
• The bottom of the floor is insulated and located on grade.
• The heating cable is in conduit embedded in concrete, sand, or soil. If you are
using a different medium, contact Raychem for an analysis.
If any of these design assumptions do not apply to your application, contact
your Raychem representative for design assistance.
5.4
Design: Determining Heating
Cable Spacing
Determine Freezer Temperature
Determine the temperature at which your freezer operates.
If it operates at more than one temperature, or if the operating temperature may
be changed in the future, base the spacing selection on the lowest anticipated
operating temperature.
Freezer temperature (°F)
Record Insulation R-Value
The insulation R-value is the thermal resistance of the floor’s insulation.
Normally the R-value will be printed on the insulation material. However, if that
is not the case, you can calculate it by dividing the insulation thickness in inches
by the insulation thermal conductivity.
Insulation R-value (h-ft 2/Btu)
Determine Conduit Spacing
Use the freezer operating temperature and the floor insulation R-value to select
the correct conduit spacing from Table 5.2 on the next page. If your calculated
R-value or freezer operating temperature does not match the values in Table
5.2, use the values that give the closer heating cable spacing.
Within each cell, there are two numbers, one for conduit spacing and one for
freezer load.
Freezer load is the additional cooling load imposed on the cooling system by the
freezer-frost-heave-prevention heating cable. It is the heat transferred through
the insulation into the freezer, expressed in watts per square foot of floor area.
24
RaySol System
Design Guide
5. Freezer Frost
Heave Prevention
Table 5.2. Conduit Spacing and Freezer Load
Floor insulation R-Value (h-ft2/Btu)
Freezer
temperature
R-10
R-20
R-30
R-40
30°F
Conduit spacing
Freezer load
96
0.7
96
0.4
96
0.3
96
0.3
20°F
Conduit spacing
Freezer load
81
0.8
96
0.5
96
0.4
96
0.3
10°F
Conduit spacing
Freezer load
63
1.0
96
0.6
96
0.4
06
0.3
0°F
Conduit spacing
Freezer load
51
1.3
84
0.8
96
0.5
96
0.4
-10°F
Conduit spacing
Freezer load
42
1.5
72
0.8
96
0.6
96
0.5
-20°F
Conduit spacing
Freezer load
36
1.8
63
1.0
87
0.7
96
0.6
-30°F
Conduit spacing
Freezer load
33
2.0
57
1.1
78
0.8
93
0.6
-40°F
Conduit spacing
Freezer load
30
2.3
51
1.2
69
0.8
84
0.7
Note: Conduit spacing is expressed in inches; freezer load is expressed in watts per square foot (W/ft 2).
Conduit spacing (inches)
Freezer load (W/ft2)
5.5
Layout: Laying Out Heating
Cable and Components
Prepare Scale Drawing
In preparation for laying out each heating cable circuit, draw to scale the freezer
floor area to be heated. Note the limits of the heated area carefully. Show all
concrete joints on the drawing and note the location and size of obstacles such
as floor drains, pipe penetrations, conduit runs, columns, and fixtures.
Estimate Number of Circuits
The amount of heating cable and the number of heating cable circuits can be
estimated before a detailed layout is done if the conduit spacing, area dimensions, and the available branch circuit breaker rating are known.
Based on the rating of the circuit breaker and voltage, determine the maximum
length of heating cable allowed per circuit breaker from Table 5.3, which follows.
Table 5.3. Maximum Circuit Length in Feet (40°F Start-up)*
Cable operating voltage
Circuit breaker rating
120 V
208 V
220 V
240 V
277V
30 amps
240
410
410
425
430
20 amps
160
275
275
280
290
15 amps
120
205
205
210
215
*For start-up temperatures less than 40°F, contact your Raychem representative.
Maximum circuit length (feet)
25
RaySol System
Design Guide
5. Freezer Frost
Heave Prevention
Let side "A" be the side the conduit runs parallel to. Side "A" cannot be greater than
the maximum circuit length. Let side "B" be the side that is perpendicular to the
conduit runs. Refer to Figures 5.2 and 5.3 for examples of side A and side B.
The number of estimated conduit runs is calculated as follows:
Estimated number =
of conduit runs
Side B (ft) x 12
Conduit spacing (in)
Round the estimated number of conduit runs to the next larger whole number.
Estimated number of conduit runs
Estimate the total heating cable length as follows:
Est. no. of
Est. heating
allowComponent
= Side A (ft) x conduit runs + End
ances (ft) + allowances (ft)
cable length (ft)
Estimated heating cable length (feet)
The end allowance (usually 48 inches per end) is the length of heating cable
installed in protective conduit between the heated floor and the power connection junction box. The component allowance (usually 24 inches per end) is the
length of heating cable inside the power connection junction box.
When the maximum circuit length is greater than or equal to side A times two,
then the conduit run can be looped into the hairpin layout (Figure 5.2). In a hairpin configuration, when you have an odd number of circuits, one circuit will be a
straight run.
If maximum circuit length (ft) ≥ 2 x side A (ft), then
Estimated number of circuits = Number of conduit runs
2
When the maximum circuit length is less than side A times two, then use a
straight run layout (Figure 5.3).
If maximum circuit length (ft) < 2 x side A (ft), then
Estimated number of circuits = Number of conduit runs
Round the number of circuits to the next larger whole number.
Estimated number of circuits
Locate Junction Boxes
The heating cable connects to the branch circuit wiring in a junction box using a
RaySol FTC-XC power connection and end seal. The heating cable is routed
from the subfloor to a junction box located above grade through protective conduit. In most freezer-frost-heave-prevention applications, separate junction
boxes are used for the power connection and end seal.
26
5. Freezer Frost
Heave Prevention
Two basic types of heating cable layouts are used:
• The hairpin layout (Figure 5.2) is used both in smaller freezers where it results
in material and labor savings over the straight run layout (Figure 5.3), and in
other freezers where only one wall of the freezer is accessible for mounting
junction boxes.
• The straight run layout (Figure 5.3) is used when the freezer dimension
exceeds one-half the maximum heating cable circuit length (insufficient heating cable allowed for a run down and back).
96" typ.
48" typ.
96" typ.
160'
80'
Side B
Figure 5.2. Hairpin layout
Side A
48" typ.
Side A
RaySol System
Design Guide
80'
Side B
Figure 5.3. Straight run layout
Lay Out Heating Cable
After determining the approximate total length of heating cable, the number of
circuits, and the junction box location, do a trial layout. In making the trial layout,
follow these recommendations:
• Start and end each circuit in a junction box. The power connection and end
seal may be located in the same box or in different boxes.
• Do not design more than one run of heating cable per conduit.
• Arrange the conduit so it uniformly covers the area to be heated.
• Maintain the design conduit spacing within 4 inches.
• Do not extend the heating cable beyond the room or area in which it originates.
• Do not cross expansion, crack control, or other subfloor joints.
• Do not route the conduit closer than 4 inches to the edge of the subfloor,
drains, anchors, or other material in the concrete.
• Do not exceed the maximum length of heating cable allowed on a branch circuit breaker as given in Table 5.3. The maximum length includes the heating
cable covering the floor as well as the heating cable in the junction box and
protective conduit.
• The maximum length of heating cable that can be pulled through conduit is
450 feet. The maximum total degree of conduit turn is 360 degrees.
• Do not install RaySol heating cable in ceilings or walls.
• When the combined lengths of two or more circuit runs are less than the maximum circuit length allowed, these runs can be combined in one circuit breaker.
27
RaySol System
Design Guide
5. Freezer Frost
Heave Prevention
Record Circuit Information
Reconstruct the trial circuit layout until the design meets all of the previous recommendations. Record the total length of heating cable used on each circuit.
Assign each circuit to a circuit breaker in a specific panel board and record each
circuit length.
Actual cable length per circuit (feet)
5.6
Electrical Design: Selecting and
Sizing Electrical Parameters
Select Cable
Select the RaySol heating cable that matches your operating voltage:
• RaySol 1: 110–120 volts
• RaySol 2: 208–277 volts
Cable
Select Branch Circuit Breaker Size
Record the circuit breaker rating to be used.
Use ground-fault protection devices (GFPDs) for all RaySol applications.
Ground-fault protection devices with a 30-mA trip level are available from
Westinghouse (GFEPD) and Square-D (QO-EPD). If operating at 277 volts, use
a Raychem TraceGuard 277 GFPD.
WARNING: To minimize the danger of fire from sustained electrical arcing
if the heating cable is damaged or improperly installed, use a ground-fault
protection device (GFPD) with a nominal 30-milliampere (mA) trip level.
Arcing may not be stopped by conventional circuit breakers.
Circuit breaker rating (amps)
Select Maximum Length of Heating Cable per Branch Circuit
Based on the layout and using the circuit breaker rating, select from Table 5.3
the maximum length of heating cable allowed on a branch circuit.
Maximum circuit length (feet)
Select Junction Box
For the heating cable power connection and end seal, select a UL Listed and
CSA Certified junction box that is suitable for the location. Use a box with a minimum internal volume of 16 cubic inches if the box is metallic and 19 cubic
inches if the box is not metallic.
The junction box containing the RaySol power connection and end seal must be
accessible. According to the National Electrical Code, “accessible” is defined as
1) capable of being removed or exposed without damaging the building structure or finish, or 2) not permanently closed in by the structure or finish of the
building. Refer to Article 370-19 of the National Electrical Code for restrictions
on junction box location.
Size Transformer
Calculate the total transformer load as:
Total cable length (ft)
Transformer = 0.8 x Circuit breaker x
x Voltage
load (W)
rating (A)
Maximum circuit length (ft)
Transformer load (watts)
28
RaySol System
Design Guide
5. Freezer Frost
Heave Prevention
Select Controls (optional)
Temperature controls are not normally used with the RaySol freezer-frostheave-prevention system. The self-regulating heating cable automatically
reduces its power output as the freezer subfloor temperature rises so that a
thermostat is not necessary to provide high-temperature limit protection or to
protect the heating cable. And since the heat output of the system is low, the
energy savings realized by control of the subfloor temperature is small and often
not worth the potential maintenance problems presented by use of temperature
control devices.
For cases where temperature control or temperature monitoring is desired, use
a thermostat with a remote sensing bulb similar to the Raychem AMC-1B.
Locate the thermostat sensing bulb at the same elevation as the heating cable
and midway between adjacent runs of cable. Keep the sensing bulb as far from
the walls of the freezer as possible.
5.7
Example
This example is based on Figure 5.3 on page 27. It represents a freezer-floor
frost-heave-prevention application where the freezer temperature is -20°F and
the floor is insulated to R-40.
Heating cable spacing of 96 inches was selected from Table 5.2 on page 25.
Twenty-four inches of heating cable per end was allowed for the component
allowance, and 48 inches per end for the end allowance.
The estimated heating cable length was calculated as follows (based on the formula on page 26):
Estimated heating
80 ft x 160 ft x 12
=
+ 80 ft + 40 ft = 1720 ft
cable length
96 in
After the layout was finalized, the actual length of heating cable used was 1730
feet in ten circuits, making the length of cable per circuit 173 feet.
The circuit breaker rating is 30 amps, the voltage is 277 Vac, and the maximum
circuit length from Table 5.3 is 430 feet.
The transformer load per circuit was calculated as follows (based on the formula
on page 28):
Transformer load = 0.8 x 30 A x
173 ft
x 277 Vac = 2675 W
430 ft
29
RaySol System
Design Guide
30
RaySol System
Design Guide
6. Condensed Specification
Guide
This is the product portion of a specification for the RaySol System. For a complete specification that includes installation and testing recommendations, contact your Raychem representative.
6.1 Floor Warming and Heat Loss
Replacement
PART 1 – GENERAL
1.1 Furnish and install a UL Listed and CSA Certified (select: concrete floor
warming or heat loss replacement) system composed of RaySol heating
cable, components, and controls.
PART 2 – PRODUCTS
2.1 The heating cable and termination components shall be UL Listed for
Radiant Heating and CSA Certified for Designation 1B.
2.2 The self-regulating heating cables shall consist of two (2) nickel-copper bus
wires embedded in parallel in a radiation-crosslinked polymer core that
varies its power output in response to temperature all along its length,
allowing the heating cable to be installed in conduit without overheating, to
be cut to length in the field, and to have no heating-cable-to-cold-lead
connections buried in the slab. The heating cable shall be covered with a
radiation-crosslinked modified polyolefin dielectric jacket and protected by a
tinned-copper braid and a fluoropolymer outer jacket. A constant-wattagetype heating cable is not acceptable.
2.3 The heating cable shall operate on (select: 110, 120, 208, 220, 240, or
277) volts without the use of transformers.
2.4 The heating cable shall be RaySol 1 or RaySol 2 as manufactured by
Raychem Corporation.
2.5 The power connection, end seal, and splice kits shall be applied in the field.
2.6 Each circuit shall be protected by a 30-mA ground-fault protection device.
PART 3 – PERFORMANCE
3.1 The heating cable shall meet the following performance criteria:
• For floor heat loss replacement: A minimum temperature of 70°F (± 5°F)
or 2 watts/ft2.
• For floor warming: A minimum temperature of 80°F (±5°F) or 6 watts/ft2.
• A maximum thermal output at 40°F of 16.5 watts/ft.
3.2 The heating cable spacing shall be determined by an application-specific,
steady-state, finite-difference, thermal analysis of the floor to be warmed.
3.3 The program output shall show slab temperature based on the depth and
thermal conductivities of the floor layers, ambient temperatures, voltage,
and heating cable output. A copy of the program output shall be submitted
to the engineer for approval.
PART 4 – INSTALLATION
4.1 The heating cable shall be installed according to the manufacturer's recommendations, the instructions supplied with the heating cable and components, and the instructions in the RaySol Installation Manual (H54693).
4.2 If in conduit, the heating cable shall be installed at least 11/2 inches below
the finished surface of the floor at the spacing indicated on the drawings.
4.3 The heating cable shall be protected from damage during installation.
Heating cable repairs and splices shall be made using a splice kit provided
by Raychem.
PART 5 – TESTING
5.1 After installation, prior to concrete pour, the cable shall be meggered at
2500 Vdc, from conductor to braid. Resistance readings shall be 20 megohms
to infinity. After concrete pour, the cables shall be retested. Submit test record
to the engineer.
31
RaySol System
Design Guide
6. Condensed Specification
Guide
6.2 Tile and Marble Floor Warming
PART 1 – GENERAL
1.1 Furnish and install a UL Listed and CSA Certified tile and marble floor
warming system composed of RaySol heating cable, components, and
controls.
PART 2 – PRODUCTS
2.1 The heating cable and termination components shall be UL Listed for
Radiant Heating and CSA Certified for Designation 1B.
2.2 The self-regulating heating cables shall consist of two (2) nickel-copper bus
wires embedded in parallel in a radiation-crosslinked polymer core that
varies its power output in response to temperature all along its length,
allowing the heating cable to be installed in conduit without overheating, to
be cut to length in the field, and to have no heating-cable-to-cold-lead
connections buried in the slab. The heating cable shall be covered with a
radiation-crosslinked modified-polyolefin dielectric jacket and protected by a
tinned-copper braid and a fluoropolymer outer jacket. A constant-wattagetype heating cable is not acceptable.
2.3 The heating cable shall operate on (select: 110 or 120) volts without the
use of transformers.
2.4 The heating cable shall be RaySol 1 as manufactured by Raychem
Corporation.
2.5 The power connection, end seal, and splice kits shall be applied in the field.
2.6 Each circuit shall be protected by a 5-mA sensitivity ground-fault protection
device.
PART 3 – PERFORMANCE
3.1 The heating cable shall meet the following performance criteria:
• The floor temperature shall be maintained above 80°F.
• The maximum thermal output at 40°F shall be 16.5 watts/ft.
3.2 Heating cable spacing shall be determined by an application-specific,
steady-state, finite-difference, thermal analysis of the floor to be warmed.
3.3 The program output shall show slab temperature based on the depth and
thermal conductivities of the floor layers, ambient temperatures, voltage,
and heating cable output. A copy of the program output shall be submitted
to the engineer for approval.
PART 4 – INSTALLATION
4.1 The heating cable shall be installed according to the manufacturer's recommendations, the instructions supplied with the heating cable and components, and the instructions in the RaySol Installation Manual (H54693).
4.2 The heating cable shall be protected from the setting bed to the junction
box by installing it inside 1/2-inch-minimum EMT conduit or rigid plastic or
metal conduit.
4.3 The protective conduit shall be extended at least 6 inches into the setting
bed. Install bushings on both ends of the conduit.
4.4 The heating cable shall be protected from damage during installation.
Heating cable repairs and splices shall be made using only approved splice
kits provided by Raychem.
PART 5 – TESTING
5.1 After installation of the heating cable, prior to placing the mortar setting bed,
the heating cable shall be meggered at 2500 Vdc, from conductor to braid.
Resistance readings shall be 20 megohms or greater. After placing the setting bed, the cables shall be retested. Do not install tile or marble over heating cables that fail the Megger test. After the floor is complete, repeat the
test and submit test records to the engineer. Do not energize heating
cables with Megger readings of less that 20 megohms.
32
RaySol System
Design Guide
6. Condensed Specification
Guide
6.3 Freezer Frost Heave Prevention
PART 1 – GENERAL
1.1 Furnish and install a UL Listed and CSA Certified freezer-frost-heaveprevention system composed of RaySol heating cable, components, and
controls.
PART 2 – PRODUCTS
2.1 The heating cable and termination components shall be UL Listed for
Radiant Heating and CSA Certified for Designation 1B.
2.2 The self-regulating heating cables shall consist of two (2) nickel-copper bus
wires embedded in parallel in a radiation-crosslinked polymer core that
varies its power output in response to temperature all along its length,
allowing the heating cable to be installed in conduit without overheating, to
be cut to length in the field, and to have no heating-cable-to-cold-lead
connections buried in the floor. The heating cable shall be covered with a
radiation-crosslinked modified-polyolefin dielectric jacket and protected by a
tinned-copper braid and a fluoropolymer outer jacket. A constant-wattagetype heating cable is not acceptable.
2.3 The heating cable shall operate on (select: 110, 120, 208, 220, 240, or 277)
volts without the use of transformers.
2.4 The heating cable shall be RaySol 1 or RaySol 2 as manufactured by
Raychem Corporation.
2.5 The power connection and end seal shall be applied in the field.
2.6 Each circuit shall be protected by a 30-mA ground-fault protection device.
PART 3 – PERFORMANCE
3.1 The heating cable shall meet the following performance criteria:
The subfloor temperature at the coldest section in contact with either
sand or soil shall be 40°F, with the freezer load (cooling load imposed
on the system by the frost heave prevention) ranging between but not
exceeding 0.3 to 2.3 watts/ft2 depending on the R-factor of the floor insulation and cable spacing.
3.2 Heating cable spacing shall be determined by an application-specific,
steady-state, finite-difference, thermal analysis of the floor to be warmed.
3.3 The program output shall show slab temperature based on the depth and
thermal conductivities of the floor layers, ambient temperatures, voltage,
and heating cable output. A copy of the program output shall be submitted
to the engineer for approval.
PART 4 – INSTALLATION
4.1 The heating cable shall be installed according to the manufacturer's recommendations, the instructions supplied with the heating cable and components, and the instructions in the RaySol Installation Manual (H54693).
4.2 The heating cable shall be installed in conduit according to the manufacturer’s
instructions.
4.3 The conduit shall be extended to the junction box. Do not use wire pulling
compound. No splices within the conduit are allowed.
PART 5 – TESTING
5.1 After installation, prior to concrete pour, the heating cable shall be meggered at 2500 Vdc, from conductor to braid. Resistance readings shall be
20 megohms to infinity. After concrete pour, the cables shall be retested.
Submit test record to the engineer.
33
RaySol System
Design Guide
34
RaySol System
Design Guide
7. Appendix A
Warranty; Suitability
(a) Raychem warrants products delivered hereunder against faulty workmanship and use of defective materials for a period of eighteen (18) months from
the date of installation or twenty-four (24) months from the date of shipment,
whichever is sooner. When the contract calls for systems design, drawings,
technical advice, services or instructions (collectively “Services”) by Raychem,
in connection with the products, Raychem further warrants for the above stated
warranty period solely that such Services will be undertaken in accordance with
Raychem’s reasonable technical judgment based on Raychem’s understanding
of the pertinent technical data as of the date of performance of such Services.
The foregoing warranty with respect to products shall not be enlarged or affected by, and (except as expressly provided herein) no obligation or liability shall
arise or grow out of, Raychem’s rendering Services in connection with the products. Such warranty is the only warranty made by Raychem and it can be
amended only by a written instrument signed by a duly authorized officer of
Raychem. If the products furnished by Raychem hereunder are determined to
contain a deficiency, Buyer’s exclusive remedy shall be to have Raychem repair
such products or supply replacement products or credit Buyer’s account for
such products and accept their return, whichever Raychem may elect in its sole
discretion. Notwithstanding the foregoing sentence, in no circumstances shall
Raychem have any liability or obligation with respect to expenses, liabilities, or
losses associated with the installation or removal of any products or the installation of replacement products or for any inspection, testing, or redesign occasioned by any deficiency or by the repair or replacement of products.
Raychem’s obligations are subject to the further condition that Raychem shall
have no liability whatsoever for any deficiency unless (i) Raychem is notified in
writing promptly (and in no event later than 30 days) after discovery by Buyer of
the alleged deficiency, which notice shall include a detailed explanation of the
alleged deficiency, (ii) the products containing the alleged deficiency are
promptly returned to Raychem, F.O.B. Raychem’s plant, and (iii) Raychem’s
examination of such products discloses to Raychem’s satisfaction that such
alleged deficiency actually exists and occurred in the course of proper and normal use and was not caused by accident, misuse, neglect, alteration, or improper installation, repair, or testing. If any products so prove to contain a deficiency
and Raychem elects to repair or replace them, Raychem shall have a reasonable time to make such repair or replacement.
THE FOREGOING WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES,
EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT, AND OF ANY OTHER OBLIGATION ON
THE PART OF RAYCHEM.
(b) It shall be the responsibility of the Buyer to determine, on the basis of the
most current written technical data, the suitability of the products and of any
systems design or drawings for the intended use and their compliance with
applicable laws, regulations, codes, and standards and the Buyer assumes all
risks pertaining thereto.
35
®
R
LISTED
9J86
Radiant
Heating Cable
DESIG. 1B
Raychem Corporation
Construction Products Group
300 Constitution Drive
Menlo Park, California 94025-1164
Tel (800) 542-8936
Fax (650) 361-5579
All of the above information, including illustrations, is believed to be reliable. Users, however,
should independently evaluate the suitability of each product for their application. Raychem
makes no warranties as to the accuracy or completeness of the information, and disclaims
any liability regarding its use. Raychem’s only obligations are those in the Standard Terms
and Conditions of Sale for this product, and in no case will Raychem be liable for any incidental, indirect, or consequential damages arising from the sale, resale, use, or misuse of
the product. Specifications are subject to change without notice. In addition, Raychem
reserves the right to make changes—without notification to Buyer—to materials or processing that do not affect compliance with any applicable specification.
Raychem Canada Ltd.
6303 Airport Road
Mississauga, Ontario
Canada L4V 1N4
Tel (800) 387-3993
Fax (905) 671-0972
ISO 9 0 0 1
©1994 Raychem Corporation Printed in USA H54994 2/95
RaySol and TraceGuard 277 are trademarks of Raychem Corporation.
Raychem is a registered trademark of Raychem Corporation.
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