Do not pussyfoot with outdoor electrical leakage. I have found issues like yours, and ended up finding underground splices where they just sliced the wires with wirenuts or electrical tape, and covered then back up! If these are tripping the GFCI, abandon those wires and run new cable. Your insurance company will be grateful!Hi all. I am stumped.
Yesterday I did a few minor updates on a home that was wired in the 80s.
I will try to be brief.
There is a (surface mount) receptacle on an outside wall of a home for a deck area, the deck is 30 ft x 30 ft and other than 30 feet away the deck it 100% closed in and water tight, under no circumstances can any snow or rain come anywhere near the receptacle, nor do they use this receptacle to plug in any power tools or anything else for use "off" of the deck.
Out of the top of the PVC receptacle box is 1/2 inch PVC conduit up to a water proof switch that feeds four light in the deck area. Coming out of the bottom of the surface mounted PVC receptacle box there are two, 12/2 NMWU wires that feed two sheds (via under the ground) in the back yard. Each shed has one receptacle and one light. Neither are GFCI protected. So I decided to replace the receptacle on the deck with a GFCI receptacle to protect the two sheds.
The bottom line? Once the GFCI receptacle was installed, it trips. Every time.... When I disconnect the two 12/2 NMWU wires that feed the sheds it doesn't trip, The GFCI operates fine as a receptacle and as a feed for the lights, but again, hook up the two 12/2 NMWU wires for the sheds,,,,,it trips.
I have carefully inspected the visible part of the 12/2's under the deck (before they go underground) and they are fine.
I inspected the 12/2 s from the entry points in the shed to where they enter a junction box, the wires are fine. I disconnected everything from the junction box except the incoming feed and capped off the wires and after doing so, still the GFCI on the deck trips.
There must be a short or something wrong under the ground between the deck and the sheds, no?
Also. I tried connecting the 12/2 NMWU's independently, one at a time, and once each one is connected by itself, the GFCI trips. The only difference is when I connect one of them to the GFCI it trips instantly, the other trips after about 3 seconds.
I am sorry this is such a long drawn out explanation but I wanted to give as much info as I could. It has to be a fault in the 12/2 under the ground, no?
Any ideas or suggestions will be much appreciated.
P.S. Everything works fine if the deck receptacle is not a GFCI.
With the deck receptacle standard, not GFCI, I temporarily, installed a GFCI receptacle in one of the sheds, and it works fine. (just some added info)