![background image](http://html.mh-extra.com/html/pentair/raychem-icestop/raychem-icestop_installation-and-operation-manual_1524280053.webp)
49
6
Commissioning and Preventive
Maintenance
Raychem-IM-H58067-IceStopRoofGutterDeIcingCOM-EN 18/01
WARNING: The heating cable can store a large
electrical charge after the insulation resistance
test is performed. To prevent personal injury from
electrical shock, fully discharge the cable prior to
disconnecting the megohmmeter. The megohmme-
ter may discharge automatically. However, it may
be necessary to short the cable leads. Contact your
supervisor or the instrument manufacturer to verify
the safest practice.
Using a megohmmeter, test insulation resistance at
three voltages—500, 1000, and 2500 Vdc. Significant
problems may not be detected if the insulation
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 heat-
ing cable is installed on a metal gutter, downspout,
and/or metal roof, measure the insulation resistance
between the braid and the metal surface.
Procedure
1. Disconnect all power to the heating cable, ther-
mostat, and contactor.
2. Set test voltage at 0 Vdc.
3. Connect the negative lead (–) to the heating
cable metallic braid.
4. Connect the positive lead (+) to both heating
cable bus wires.
2500 Vdc
Megohmmeter
Braid pigtail
Bus
wires