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asking for a friend, seriously. Buried line, long enough that digging it up probably won't happen unless we can figure out where the fault is. 120V - hot, neutral and ground. The end by the power he has temporarily connected to a plug. If he plugs it into a GFI outlet, the GFI trips. The other end isn't connected to anything, the 3 wires are separated and capped. So there's a problem somewhere in between with the hot going to ground. I'm hoping there's something that could be rented or created to figure out where the problem is. I saw a youtube video of a device with 2 probes that measures any difference in current between them. The guy using it walked the path of the buried line and stuck both probes in the ground every 2' or so. The spot where device detected a difference in current - one side had none, the other found the current moving to ground - was.
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I'm interested in the replies to this, but my apporach probably would be not to screw around with too much. Just put in a new line if it's at all possible.
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05-30-2017, 09:34 AM
(This post was last modified: 05-30-2017, 09:36 AM by JTTHECLOCKMAN.)
Lots of facts are being left out but lets start at the beginning. First off sometimes a GFCI is so sensitive that they become a pain. May need to change the GFCI. Some are better than others. If the cable is underground cable it is meant to be buried so it does not just disintegrate. You need to get a continuity tester and check if there is actually a ground between wires or to ground. If so then first check at each end of cable for nicks in the cable which could have happened when installing caps or when installing into a box or when installing into a clamp. Make sure if if it was stapled that no staples punched a hole in the cable. Check the run of the cable and look for areas where there may have been a disturbance such as new plantings or anywhere a shovel could have been used. Did this just start occurring?? Look for any sections that enter a hole in a foundation or somewhere it may have been crushed or scraped. These are the obvious things to look for. If nothing is found it maybe just as easy to run a new line in either PVC or again undergound cable.
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05-30-2017, 09:34 AM
(This post was last modified: 05-30-2017, 09:38 AM by Roly.)
Was this something that was working and quit ? Or are you just trying to see if it works. Roly
Posting at the same time as clockman agree with all he said. If it is a long run a gfci may trip due to capacitance of the line.
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(05-30-2017, 09:34 AM)Roly Wrote: If it is a long run a gfci may trip due to capacitance of the line.
This I did not know. Its a long run, at least 150'. could be closer to 200. It has not been used, yet. Resistance was measured on all 3 legs and they all are the same. Continuity was measured on all 3 legs and they are all good. There have been no disturbances since the line was buried, I suppose a rock could have crushed something when the trench was filled.
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We just went through this at our club after having some backhoe work done. After some exploratory digging and the wire wasn't broke in the most likely place. We abandoned the line and trenched in 180' of wire. 3 guys, a trenching machine, 3 hours and a new line was buried and hooked up. We spent more time screwing around trying to find the break.
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(05-30-2017, 10:21 AM)crokett™ Wrote: Resistance was measured on all 3 legs and they all are the same. Continuity was measured on all 3 legs and they are all good.
Safe to assume you also checked for continuity, or lack of continuity, between each conductor (B-W, B-G, W-G)?
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(05-30-2017, 11:13 AM)TDKPE Wrote: Safe to assume you also checked for continuity, or lack of continuity, between each conductor (B-W, B-G, W-G)?
yes. we did. the line in question would be useful, but is not critical. It was put in when a water line was put in for a garden. He's never used it. He's hoping he doesn't have to abandon it.
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(05-30-2017, 12:25 PM)crokett™ Wrote: yes. we did. the line in question would be useful, but is not critical. It was put in when a water line was put in for a garden. He's never used it. He's hoping he doesn't have to abandon it.
This is why I preach to anyone that will listen to never, ever, install direct buried wire. If a conduit had been laid in instead of cheaping out it would be a simple matter of replacing the conductors instead of the thought of trying to find the fault or worse, re-digging the entire run. 3/4" or 1" sch40 pvc is a whole lot cheaper than digging 200' of trench.
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Try connecting to a outlet that does not have a gfci, if it trips a breaker there is a problem. Roly
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