Thermon TESH - Manual (Page 24)

INSTALLATION GUIDELINES SERIES HEATING CABLES PAGE 22
THERMON...The Heat Tracing Specialists ®
TEP0118U-1111
Inspection and testing of heating cable and documentation
Before thermal insulation is installed
Inspect the heating cable for possible damages along 1.
the length of the total circuit.
Megger the heating cable to ensure electrical resistance 2.
integrity. This will verify that the cable has not been
damaged during installation of the heat trace circuit.
The cable should be tested between heating cable
bus wires and the heating cable metallic braid with a
500 - 2500 Vdc test voltage for TES and 1000 Vdc for
MI conform the local electrical board. The measured
insulation resistance shall not be less than 50 MΩ.
Measure also the loop resistance. Note down the
readings in the check list (page 23).
Caution:
In case electronic thermostats are used in the
system, disconnect them before meggering the
heat tracing system.
After thermal insulation is installed
Megger the heating cable to ensure electrical resistance 1.
integrity. This will verify that the cable has not been
damaged during installation of thermal insulation of the
heat trace circuit. The cable should be tested between
heating cable bus wires and the heating cable metallic
braid with a 500 - 2500 Vdc test voltage for TES and
1000 Vdc for MI conform the local electrical board. The
measured insulation resistance shall not be less than 50
MΩ. Measure also the loop resistance. Note down the
readings in the check list (page 23).
Caution:
In case electronic thermostats are used in the system,
disconnect them before meggering the heat tracing
system.
If applicable, inspect the heating cable at the entries in 2.
the insulation cladding and at insulation end covers.
Documentation
1. Stabilized design can be used for series heating cables
to assign a lower T-class through the use of the Thermon
CompuTrace software or Thermon Engineering.
2. If stabilized design is used, the end user must record the
system parameters and the area T-class, and keep these
records for the time the heating cable is in operation.
3. If stabilized design is used, no temperature limiting device
has to be used.
4. In non-hazardous area's a limiter can be used when the
product is the limiting factor.
Caution:
A limiter must always be installed on the heating cable.