Chromalox Big Red Book

Heating Cable

Thermal Output Ratings on Insulated Metal Pipe 1

SRF Self-Regulating Freeze Protection (cont’d.)

9 10 11 12 13 14

10 W/Ft.

8 W/Ft.

5 6 7 8

5 W/Ft.

4

Heat Output (W/Ft.)

3 W/Ft.

3 2

Cable Output vs. Temperature

1

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 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.

Thermal Output Ratings on Plastic Pipe with Aluminum Tape

Heat Output (W/Ft.) 9 8 7 6 5 4 3 2 1 SRF3

SRF10

SRF8

SRF5

Cable Output vs. Temperature

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 Pipe Temperature (°F)

Output Wattage at Alternate Voltages (W/Ft.)

% Change In Output

% Change In Output

% Change In Output

Model

208V

220V

277V

SRF 3 SRF 5 SRF 8 SRF 10

2.4 4.1

-20 -18 -14 -13

2.6 4.5

-13 -10

3.4 5.6

+15 +13 +12 +10

6.88 8.7

7.28 9.2

-9 -8

8.96

11.1

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

Cable Rating 40°F Start-Up (Ft.) -40°F Start-Up (Ft.) 20A 30A 40A 20A 30A 40A 20A 30A 40A 350 360 NR 270 360 NR 220 325 340 660 NR NR 555 660 NR 445 595 625 230 270 NR 180 270 NR 145 220 255 450 540 NR 360 540 NR 290 440 510 180 215 NR 145 215 NR 115 180 195 330 420 NR 265 395 420 210 315 400 105 160 210 90 135 180 85 125 170 210 315 420 185 275 365 145 215 300 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. 0°F Start-Up (Ft.) SRF 3-1 SRF 3-2 SRF 5-1 SRF 5-2 SRF 8-1 SRF 8-2 SRF 10-1 SRF 10-2

G-38