![background image](http://html.mh-extra.com/html/pentair/raychem-icestop/raychem-icestop_installation-and-operation-manual_1524280057.webp)
53
7
Test Procedures
Raychem-IM-H58067-IceStopRoofGutterDeIcingCOM-EN 18/01
Frequency
Insulation resistance testing is recommended at four
stages during the installation process and as part of
regularly scheduled maintenance.
• When received
• After the cables have been installed
• Prior to initial start-up (commissioning)
• As part of the regular system inspection
• After any maintenance or repair work
* Under adverse weather conditions, or when the
tails or terminal connections have evidence of
moisture, lower insulation resistances may be
encountered. Wipe tails, face of pot, and all termi-
nal connections with a clean dry rag to eliminate
moisture and retest.
Test Criteria
The minimum insulation resistance for a clean, dry,
properly installed circuit should reflect the values
shown above, regardless of the heating cable length.
7.3
Insulation Resistance (Megohmmeter) Test
The insulation resistance test is critical to ensure
the safety and reliability of the heating cable system.
This test should be performed as part of the installa-
tion of the system, and is useful for troubleshooting
an installed system.
WARNING: Shock or Fire Hazard. Disconnect
power to all circuits prior to testing.
Using a megohmmeter, test insulation resistance at
three voltages—500, 1000, and 2500 Vdc.
Significant problems may not be detected if the insu-
lation resistance is tested only at 500 or 1000 volts.
First, measure the resistance between the heating
cable bus wires and the grounding braid; then, if the
heating cable is installed on a metal gutter, down-
spout, and/or metal roof, measure the insulation
resistance between the braid and the metal surface.