King Electric SR self-reg, cut to length - Manual (Page 11)

Model Volts
Output at
32ºF (0ºC)
Maximum
Single Run
Length
SR123 120V 5.0 w/ft 273 ft. (83M)
SR243
208V 4.1 w/ft 530 ft. (129M)
240V 5.0 w/ft 547 ft. (161M)
277V 5.9 w/ft 590 ft. (180M)
SR125 120V 8.0 w/ft 216 ft. (66M)
SR245
208V 7.1 w/ft 397 ft. (121M)
240V 8.0 w/ft 432 ft. (132M)
277V 9.0 w/ft 466 ft. (142M)
SR128 120V 12.1 w/ft 171 ft. (52M)
SR248
208V 11.4 w/ft 312 ft. (95M)
240V 12.1 w/ft 347 ft. (106M)
277V 13.0 w/ft 385 ft. (117M)
SR1210 120V 14.8 w/ft 152 ft. (46M)
SR2410
208V 14.2 w/ft 274 ft. (83M)
240V 14.8 w/ft 312 ft. (95M)
277V 15.8 w/ft 346 ft. (106M)
Rev 11.04.12 www.king-electric.com 11
Technical Data Table
Maximum operating temp. 150°F (65°C)
Maximum exposure temp. 185°F (85°C)
Minimum installation temp. 0°F (-18°C)
Minimum bending radius 1”, (24 mm)
Dimensions
.496” x .236”
(12.6mm x 6mm)
Service voltage
110-120V,
208V-277V
Cable Volts
Start up
Temp
15 Amp
(ft.)
20 Amp
(ft.)
30 Amp
(ft.)
40 Amp
(ft.)
SR123 120V
32ºF (0ºC) 273 273 273 273
20ºF (-7ºC) 254 268 273 273
0ºF (-18ºC) 213 255 273 273
-20ºF (-29ºC) 182 248 273 273
SR243 240V
32ºF (0ºC) 547 547 547 547
20ºF (-7ºC) 501 547 547 547
0ºF (-18ºC) 426 547 547 547
-20ºF (-29ºC) 368 492 547 547
SR125 120V
32ºF (0ºC) 188 216 216 216
20ºF (-7ºC) 166 216 216 216
0ºF (-18ºC) 144 193 216 216
-20ºF (-29ºC) 127 173 216 216
SR245 240V
32ºF (0ºC) 381 432 432 432
20ºF (-7ºC) 331 432 432 432
0ºF (-18ºC) 292 387 432 432
-20ºF (-29ºC) 258 347 432 432
SR128 120V
32ºF (0ºC) 126 168 171 171
20ºF (-7ºC) 118 157 171 171
0ºF (-18ºC) 103 136 171 171
-20ºF (-29ºC) 92 123 168 171
SR248 240V
32ºF (0ºC) 257 342 347 347
20ºF (-7ºC) 235 311 347 347
0ºF (-18ºC) 204 268 347 347
-20ºF (-29ºC) 184 244 347 347
SR1210 120V
32ºF (0ºC) 102 143 152 152
20ºF (-7ºC) 97 126 152 152
0ºF (-18ºC) 88 117 152 152
-20ºF (-29ºC) 76 104 152 152
SR2410 240V
32ºF (0ºC) 172 226 312 312
20ºF (-7ºC) 159 215 312 312
0ºF (-18ºC) 150 197 298 312
-20ºF (-29ºC) 138 182 273 312
Table 9: Circuit Breaker Protection for Deicing Table 10: Technical Data Ratings
Table 11: Maximum Single Run Length
Technical Data Notes:
1. The maximum single cable run is the longest length of heating cable before there is a
significant voltage drop which will lower the wattage rating of the cable.
2. The circuit breaker sizes in Table 9 are per the National Electric Code (NEC).
3. The NEC requires ground-fault equipment protection (GFEP) for fixed outdoor deicing
equipment. All electrical connections should be made by a licensed electrician.
Circuit Breaker Protection and Cable Length Design for Deicing
Model 208V 277V
SR243 0.97 1.08
SR245 0.92 1.08
SR248 0.90 1.11
SR2410 0.88 1.11
Table 12: Circuit Length Adjustments
Circuit length adjustments for 240V
cables operated 208V and 277V are
noted in table 12.