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Test Procedures
Raychem-IM-H57548-HWATsystem-EN 16/08
• Before installing the cable
• Before installing components
• Before installing the thermal insulation
• After installing the thermal insulation
• Prior to initial start-up (commissioning)
• As part of the regular system inspection
• After any maintenance
or repair work
Procedure
Insulation resistance testing (using a megohm-
meter) should be conducted at three voltages; 500,
1000, and 2500 Vdc. Potential problems may not be
detected if testing is done only at 500 and 1000 volts.
First measure the resistance between the heating
cable bus wires and the braid (Test A), then measure
the insulation resistance between the braid and the
metal pipe (Test B). Do not allow test leads to touch
junction box, which can cause inaccurate readings.
Important: System tests and regular maintenance
procedures require that insulation resistance testing
be performed. Test directly from the HWAT-ECO, ACS-
30 or the junction box closest to the RayClic-PC.
WARNING: Fire hazard in hazardous locations.
Insulation resistance test can produce sparks. Be
sure there are no flammable vapors in the area
before performing this test.
Insulation resistance criteria
A clean, dry, properly installed circuit should
measure thousands of megohms, regardless of
the heating cable length or measuring voltage
(500–2500 Vdc). The following criteria are provided to
assist in determining the acceptability of an installa-
tion where optimum conditions may not apply.
• All insulation resistance values should be greater
than 1000 megohms. If the reading is lower, con-
sult Section 10, Troubleshooting Guide.
