22 | nVent.com
Power Supply and
Electrical Protection
7
7.1 Voltage Rating
Verify that the source voltage corresponds to the
heatingcable rating printed on the cable jacket and
specified by the design.
7.2 Electrical Loading
Overcurrent devices are selected according to
the heating cable type, source voltage, and circuit
length to allow start-up at the designed ambient
temperatures. The design specifies the size and
type of overcurrent device.
7.3 Ground-Fault Protection
If the heating cable is improperly installed, or
physically damaged to the point that water contacts the
bus wires, sustained arcing or fire could result. If arcing
does occur, the fault current may be too low to trip
conventional circuit breakers.
nVent, the U.S. National Electrical Code, and the
Canadian Electrical Code require both ground-fault
protection of equipment and a grounded metallic
covering on all heating cables. All RAYCHEM products
meet the metallic covering requirement. Following are
some of the ground-fault breakers that satisfy this
equipment protection requirement: Square D Type GFPD
EHB-EPD (277 Vac), Cutler Hammer (Westinghouse)
Type QBGFEP.
480-V VPL must use RAYCHEM 920, 200N, T2000, or
NGC-30 controllers only, which provide ground-fault
protection at 480 volts.
WARNING: To minimize the danger of fire from
sustained electrical arcing if the heating cable is
damaged or improperly installed, and to comply
with nVent requirements, agency certifications, and
national electrical codes, ground-fault equipment
protection must be used on each heating cable branch
circuit. Arcing may not be stopped by conventional
circuit breakers.
WARNING: Disconnect all power before making
connections to the heating cable.
