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8
Commissioning and Preventive
Maintenance
Raychem-IM-H57548-HWATsystem-EN 16/08
Charred or damaged cable must be replaced to avoid
the risk of arcing or fire.
Figure 17: Shielding the cable from the flame
Circuit length verification (capacitance test)
The installed circuit length is verified through a
capacitance measurement of the HWAT heating
cable. Compare the calculated installed length
against the system design. If the calculated length
is shorter than the system design, confirm all con-
nections are secure and the grounding braid is
continuous.
Insulation Resistance
Insulation Resistance (IR) testing is used to verify the
integrity of the heating cable inner and outer jackets.
IR testing is analogous to pressure testing a pipe and
detects if a hole exists in the jacket.
Power check
The power check is used to verify that the system is
generating the correct power output. This test can
be used in commissioning to confirm that the circuit
is functioning correctly. For on-going maintenance,
compare the power output to previous readings.
The heating cable power output per foot is calculated
by dividing the total wattage by the total length of a
circuit. The current, voltage, operation temperature
and length must be known. Circuit length can be
determined from “as built” drawings, meter marks
on the cable or with the capacitance test. The watts
per foot can be compared to the heating cable out-
