Installation Manual
Table Of Contents
12
ElectroMelt System
Design Guide
Design Steps
Circuit Breaker Rating
Use thermal-magnetic circuit breakers rated no greater than 50 amperes for
overcurrent protection. Use the lowest rated circuit breaker compatible with the
circuit lengths to be used. Use Tables 1 or 2 below to determine maximum cir-
cuit length.
Table 1. Maximum Heating Cable Circuit Length for Startup at 0°F (in feet)
Heating cable operating voltage
breaker 208 V 220 V 240 V 277 V
50 amp 245* 250* 265* 300
40 amp 200* 200* 210* 240
30 amp 145 150 160 180
20 amp 100 100 110 120
15 amp 75 75 80 90
Table 2. Maximum Heating Cable Circuit Length for Startup at 20°F (in feet)
Heating cable operating voltage
breaker 208 V 220 V 240 V 277 V
50 amp 265* 270* 285* 325
40 amp 210* 215* 230* 260
30 amp 160 165 170 195
20 amp 105 110 115 130
15 amp 80 80 85 100
*Contact RayChem for assistance, or change the voltage to 277 volts and use
TraceGuard 277. (40 and 50 amp GFPD's are not standard for these voltages).
Ground -Fault Protection Devices (GFPDs)
Use a RayChem TraceGuard 277 GFPD for 277-volt applications, up to 50
amps. Equivalent 30mA ground-leakage protection is provided by Westing-
house GFPDs or Square-D QO-EPD ground-leakage circuit breakers at 208
and 240 volts (30-amp maximum rating).
Circuit
Circuit