I have a GFCI in the garage that tripped and keeps tripping. I traced it to an outlet in the basement but there is something weird going on. I'm not an electrician, but I've done a bit of wiring, but I don't know how to interpret this.
In the picture is the basement outlet pulled apart and the power is on and the GFCI is reset and working. This basement outlet has 3 14/2 cables coming in. I think one is power from the garage, and the other two lead to outlets outside the house. I checked the wires until I found 120V and then marked them with yellow tape, which is what is shown in the image.
However, if I connect the multimeter to the black/yellow and one of the other whites I get a reading of 101.8, and the other white reads 0.7. This shouldn't be happening, right?
Not an electrician, but I have a theory. Both wires should be close to 0 since they aren't connected to the white neutral wire that goes back to the breaker box.
You know this, but don't do any of this without shutting off the breaker between changes.
Often the white neutral wire is tied to earth ground at the panel and you've left the ground wire connected to the other outlet. Something at the other end (or along the way) to the other outlet is partially tying ground back to neutral.
The white wire that you tested at 0.7 while disconnected is probably fine it doesn't have a path back to the panel. The other one is suspect. You can reconnect them one at a time and I bet the 101V run is the one that blows GFCI.
GFCI trips if the current going down the black wire isn't coming back on the white wire. That missing current is probably going to ground and not in a good way.
Water in an outdoor outlet box? Irrigation system gone bad? Bad outdoor light? Extension cord in a puddle? Staple through a wire? Etc.
Thanks for the reply.
You are right, the 101V one would trip the GFCI. I traced it to the backyard outlet. I connected everything else yesterday and left it like that and it was fine today.
I went back to it again this evening, pulled apart the basement outlet and tested them all again. It was giving 122, 0.7 and 0.7, so no weird 101 today. I wired it all back together tonight and it's not tripping. IDK what happened, but I think the outlet might have gotten wet. I pulled apart each outlet yesterday and put them back together better, but I can't remember what order I did what. I'm going to leave it like this with a lamp for the next few days on so I'll know if it trips again.
I had this happen to me when I installed a new outlet in a bedroom. I ended up rewiring every outlet and finally figured out it was when I buttoned up one of the outlets the ground was barely shorting to one of the blacks. Drove me nuts for a couple days…