Chromalox Big Red Book

HEATING CABLE

SRM/E Self-Regulating Medium Temperature (cont’d.)

Thermal Output Ratings on Insulated Metal Pipe 1

24

Cable Output vs. Temperature

20

20 W/Ft.

16

15 W/Ft.

12

10 W/Ft.

8

Heat Output (W/Ft.)

8 W/Ft.

5 W/Ft.

4

0

30 50 70 90 110 130 150 170 190 210 230 250

270 290 300

Pipe Temperature (˚F)

Note 1 — Thermal output is determined per IEEE 515-2011 Standard for testing, design installation, and maintenance of electrical resistance heat tracing section 4.1.11 Method C.

Output Wattage at Alternate Voltages (W/Ft.)

% Change In Output

% Change In Output

% Change In Output

Model

208V 3.85

220V 4.25 6.88 8.80 13.50 18.40

277V 6.45 10.24 12.50 18.45 24.40

SRM/E 5 SRM/E 8 SRM/E 10

-23 -20 -17 -15 -12

-15 -14 -12 -10

+23 +22 +20 +19 +19

6.4 8.3

SRM/E 15 12.75 SRM/E 20 17.6

-8

Circuit Breaker Selection (Max. Circuit Lengths in Ft.)

50°F Start-Up (Ft.) -20°F Start-Up (Ft.) 15A 20A 30A 40A 50A 15A 20A 30A 40A 50A 15A 20A 30A 40A 50A 0°F Start-Up (Ft.)

Cable Rating

SRM/E 5-1 SRM/E 5-2 SRM/E 8-1 SRM/E 8-2 SRM/E 10-1 SRM/E 10-2 SRM/E 15-1 SRM/E 15-2 SRM/E 20-1 SRM/E 20-2

180 360 145 285 95 190 70 145 60 115

240 480 190 380 125 255 95 190 75 155

360 720 285 575 190 385 145 290 115 230

375 750 325 650 250 490 190 385 155 305

NR NR NR NR NR NR 210 420 160 350

165 325 135 255 90 165 65 120 50 100

220 430 175 345 110 225 85 175 65 135

330 645 265 520 175 345 125 270 105 200

375 750 325 650 250 490 165 360 140 270

NR NR NR NR NR NR 210 420 160 350

155 310 130 245 85 155 60 115

210 415 165 335 100 215 80 165 65 130

310 620 250 490 170 330 120 260 100 195

375 750 325 650 245 470 150 340 135 255

NR NR NR NR 250 490 210 420 160 335

SELF-REGULATING

45 90

NR = Not Required. Maximum circuit length has been reached in a smaller breaker size. Note — Thermal magnetic circuit breakers are recommended since magnetic circuit breakers could "nuisance trip" at low temperature.

G-17