King Electric SRK08 GFEP device kit - Manual (Page 4)

Model Volts Watt/ft
Maximum
Single Run Length
SR123 120V 3 w/ft 325 ft. (99M)
SR125 120V 5 w/ft 270 ft. (82M)
SR128 120V 8 w/ft 210 ft. (64M)
SR1210 120V 10 w/ft 180 ft. (55M)
Volts
Start up
Temp.
Circuit
Breaker*
SR123
3w/ft.
SR125
5w/ft.
SR128
8w/ft.
SR1210
10w/ft.
120 V
50ºF
(10ºC)
15 Amp 325 ft. (99M) 225 ft. (69M) 145 ft. (44M) 115 ft. (35M)
20 Amp 435 ft. (133M) 270 ft. (82M) 195 ft. (59M) 150 ft. (46M)
0ºF
(-18ºC)
15 Amp 230 ft. (70M) 155 ft. (47M) 100 ft. (30M) 85 ft. (26M)
20 Amp 305 ft. (93M) 205 ft. (72M) 130 ft. (40M) 110 ft. (34M)
-20ºF
(-29ºC)
15 Amp 205 ft. (63M) 135 ft. (41M) 90 ft. (27M) 75 ft. (23M)
20 Amp 275 ft. (84M) 180 ft. (55M) 115 ft (35M) 100 ft. (30M)
Table 3: Maximum Single Cable Length
The maximum length of a single cable run is noted in Table 3
and cannot be exceeded. If the application requires a longer
cable run, then multiple cables and additional power circuits
must be used.
Circuit protection depends on the length of cable required
and the start-up temperature since the cable will draw more
power (wattage) when cold. Multiple cables can be run from
a single power circuit up to a maximum combined length as
noted in Table 5. Larger amperage circuits breakers can
handle longer combined cable lengths, but the maximum
length for a single cable run does not change. The NEC
requires the use of ground fault protection breakers for
heating cable.
Table 5: Circuit Protection Per Combined Cable Length for Pipe Freeze Protection
Circuit Breaker Protection and Cable Length Design for Pipe Freeze Protection
Rev 11.04.12 www.king-electric.com 4