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Rough-in Wiring
1. Branch circuits for the heaters shall be enclosed in 1" rigid
conduit for 05A heaters, or 1-1/4" rigid conduit for 07A
heaters.
2. Run branch circuit of proper voltage and wire size, in rigid
conduit, to location of left or right junction box as indicated on
heater wiring diagram. Wire entry to heater is through either
end pedestal.
Note When pedestal is not used for wire entry, pedestal base
must be covered with cover plate (supplied with pedestal). See
Figure 2.
3. When installing heaters on existing floors, the threaded end
of the rigid conduit must extend 7/8" to 1" above finished con-
crete. Conduit must be threaded a minimum of 3/8" .
4. Basic heaters are prewired and can be connected to branch
circuit at either end. Heaters with controls are prewired for
connection to branch circuit at one end only (refer to heater
wiring diagram), however, heater can be wired from opposite
end by running wires through heater wireway.
5. If it is necessary to run wires through the heater wire way,
use Table B to size the field installed wiring.
6. The factory installed wires in the heater wireway can be
loaded up to 35 amps in 05A units and up to 45 amps in 07A
units. Refer to Table C and D for maximum length of heater
run when the heaters are connected in parallel.
IF THE FACTORY INSTALLED WIRES IN THE WIREWAY ARE
USED TO CONNECT THE BUILT-IN CONTROLS, LIMIT THE
MAXIMUM CURRENT TO THE VALUES LISTED
Thermostat
24 amps @ 120-240 VAC
22 amps @ 277 VAC
Pilot duty– 125 VAC (all voltages)
Transformer relay
907 and 911 Series:
22 amps @ 120-240 VAC
19 amps @ 277 VAC
913 Series:
25 AMPS @ 120-240 VAC
22 AMPS @ 277 VAC
Power relay
25 amps @ 120-277 VAC- see wiring dia-
gram on heater
Disconnect switch
20 amps @ 120-277 VAC
Table B. Sizing Field Installed Wiring
Copper
Maximum no.
wire size
of wires
75º C
in wireway
No. 12 AWG
9
No. 10 AWG
8
No. 8 AWG
4
Table C. Maximum Length of Heater Run
(907 and 911-1Ø)
Watts/Ft. of
Maximum allowable length of heater run (feet)
the heaters
120 Volts
125
33
188
22
250
16
Note: For mix of watt densities, calculate amp draw. Do not
exceed values indicated in step 6 above.
Maximum allowable current
Up to 3
4 to 6
7 thru 9
Conductors Conductors Conductors
11.5 amps
9.3 amps
8.1 amps
17.4 amps
14.0 amps
12.1 amps
24.0 amps
21.0 amps
208 Volts
240 Volts
277 Volts
58
67
38
44
29
33
TABLE D. Maximum Length of Heater Run
(913 - 1Ø and 3Ø)
Watts/Ft. of
the Heaters 208 Volts
1Ø
125
74
188
49
250
37
376
24
500
18
564
16
625
14
750
12
7. Standard 75˚C wiring must be used in junction boxes,
way and blank sections.
Room Layout
Refer to heating plans for exact room arrangements of heaters
(with or without thermostat and/or relays and/or switches and
accessories.)
Mounting Height
Refer to Figure 1a. for typical mounting of heaters and pedestals
embedded in floor; refer to Figure 1b. for surface-mounted
heaters and pedestals.
Note: Up to 3/4" thick floor covering, such as carpet, tiles,
linoleum, etc., may be installed around and under the heater.
Heater Capacity
(Watts.Ft. Heater Length)
125, 188 and 250 Watts/Ft.
376, 500, 564, 625 and 750
Watts/Ft.
Leveling
Nut
Locknut (Do
Not Loosen
Or Remove)
Floor
Line
Pedestal
Figure 1a. Pedestal Embedded in Floor
Heater Catalog Number
907 and 911
913
Leveling
Nut
–
Locknut (Do
Not Loosen
Or Remove)
Floor
Line
77
51
38
Rigid
Conduit
Figure 1b. Surface-Mounted Pedestal
3
Maximum Allowable Length of Heater Run (Feet)
208 Volts
240 Volts
3Ø
1Ø`
-
86
-
57
-
43
-
28
-
21
27
19
24
17
20
14
Heater
Dimension "A"
(Minimum Mounting
Height Above Floor)
1-3/4"
3"
Welded
Heater
Bracket
Locknut
A
B
3/8"
Height Above Floor (Dim. "A)
Min.
2-5/8"
3-7/8"
Welded
Heater
Bracket
Locknut
Pedestal
A
240 Volts
277 Volts
3Ø
1Ø
-
99
-
66
-
49
-
33
-
24
32
22
29
19
24
16
wire-
Pedestal
Dimension "B"
(Minimum Height
Above Floor)
2"
3-1/4"
2-7/8" (5" Heaters)
4-1/8" (7" Heaters)
Max.
3-3/8"
4-5/8"
Base Mounting
Holes - 1/4" DIa.
(Suitable
Fasteners By
Others)
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