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Help confirming a ground fault in underground cable

668 Views 3 Replies 3 Participants Last post by  Wally4320
This is a follow-up and change to a posting made a few days ago. We have a 10-2 UF cable (not 12-2 as previously posted) going underground 20 feet to a driveway lamp post. The GFCI for the circuit was tripping. The black and white wires were isolated at both ends. Black to ground and white to ground read 60 K-ohms. A nick in the underground wire was found and that section cut out. At that point the multimeter reading became 11 M-ohm black to ground and white to ground, and zero continuity from black to white. Is this normal in an underground situation? Or should there always be absolutely zero continuity (infinite resistance) regardless of the location of the wire. This is important to know because we do not want to dig up and replace the UF cable unnecessarily. As a test, a second UF cable buried in the yard that is not tripping its GFCI and is operating correctly was isolated at both ends and gave a resistance reading of appx. 6 M-ohms. Is this acceptable, or does it indicate a ground fault that is not significant enough to trip the breaker? Many thanks.
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theoretically, a conductive path of 20,000 ohms will allow the 6 ma to pass on a 120vac circuit. the 6ma is the threshold of most GFCI devices to trip.

it seems there is a breach in the insulation of some sort if there is anything other than infinity ohms (open) on separate conductors. i would borrow another meter to verify. make sure your hands are not in the circuit.
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