GFCI keeps tripping

[Jleidolph1]

We ran a 40 amp service from the main house to a detached garage. Ran romex to a junction box, in the crawl space, to PVC with THHN to the garage. We drove 2 ground rods at the subpanel in the detached garage, and also bonded the gas line, which was buried in the trench with our service. There are 3 circuits in the panel, (yeah the 40A service was overkill), one for lighting, one for the heater, and one for the plugs. First plug we hit the GFCI and jump around to about 5 plugs inside the garage and 2 plugs outside the garage. The GFCI tripped to the point where it wouldn’t reset anymore. We replaced the GFCI thinking that was the issue, but the new one tripped as well. So after pulling out plugs and checking wirings, especially the outside plugs in case they got wet, nothing seemed to be touching, or wet and the GFCI reset and held. We were able to test the garage door opener, and everything was working perfect. Get a call today, that the GFCI tripped again and won’t reset. Any ideas as to what the issues would be? Figured it there was any wiring problems, we wouldn’t be able to get the GFCI to reset without it tripping again.

 

[ptonsparky]

Welcome to the forum.
Describe exactly what you have done, down to the number of conductors you have as you transition from one wiring method to the other. The bonding etc.

We don’t know your skill level.

 

[Little Bill]

First off, just a manner of semantics, you have a feeder not a service.

As far as the GFCI tripping. I would ask them, or check for yourself what is plugged in. Then unplug anything that is plugged in. Reset the GFCI, if it holds, plug one thing at a time in and see if you can catch what is tripping it. Sometimes people don't think or maybe just won't tell you the whole story. It could be as simple as a heater with a bad cord or even a faulty phone charger.

 

[tom baker]

Sounds like you checked wiring, a GFCI will trip with a neutral to ground fault. GFCI tripping is almost never a bad GFCI

 

[kwired]

On top of what others said, if there is nothing plugged in and it still trips, time to meg the branch circuit conductors to look for ground faults in permanent wiring.

Also try disconnecting conductors from load side of GFCI and see if it holds with just the supply conductors connected.

* make sure you don't have any mix up with line and load connections on the GFCI. GFCI receptacles currently being made may stay set with line/load reversed, but won't reset once they are tripped with line and load reversed. Can't speak for all brands but P&S does what I just said.

 

[Little Bill]

On top of what others said, if there is nothing plugged in and it still trips, time to meg the branch circuit conductors to look for ground faults in permanent wiring.

Also try disconnecting conductors from load side of GFCI and see if it holds with just the supply conductors connected.

* make sure you don't have any mix up with line and load connections on the GFCI. GFCI receptacles currently being made may stay set with line/load reversed, but won't reset once they are tripped with line and load reversed. Can't speak for all brands but P&S does what I just said.

The P&S ones I use won't even set to start with if line/load is reversed. I always listen for the "pop" when I first power them up. If I don't hear that I figure that I (or someone else) may have not connected a wire or they are reversed. Most times it is line/load reversed.

 

[acin]

THHN? in ug pvc. thhn-2 or thwn is what you use. correct me if im wrong

 

[kwired]

The P&S ones I use won't even set to start with if line/load is reversed. I always listen for the "pop" when I first power them up. If I don't hear that I figure that I (or someone else) may have not connected a wire or they are reversed. Most times it is line/load reversed.

I think they are "tripped" when manufactured. may possibly get the reset button pressed while not powered - it will stay "in" when not powered but will pop back out when power is applied and is likely why they almost always trip when new and first time you power them.

I have played with them a little - if you successfully get it reset (normally needs to be powered to do so) then power it down and reverse line/load connections it will stay set when you power it back up. But once you trip it it won't reset again if line/load are reversed. Again this for P&S not sure if others are the same way or not. I mostly only use P&S and am most familiar with them.

 

[ptonsparky]

THHN? in ug pvc. thhn-2 or thwn is what you use. correct me if im wrong

I don’t know when I’ve ever seen anything but dual rated in the smaller sizes.

 

[AC\DC]

If they are tripping with nothing in them I would find the mid point of the line and disconnect the receptacle and see if it still tripped. If so work back, and opposite if it held. If I found a bad wire in the wall I would do an insulation test on that one.

 

[Flicker Index]

Comparing an older Leviton and a newer Leviton.

Older ones are fully manually reset. The test button closes a contact to a leak resistor that causes it to trip.

Newer (post 2015) one ships in tripped position and resetting is electrically assisted while tripping is manual. If you push "test" without power, it will open. It won't close without power. If you wire it backwards, you can't close it. Here's the catch. If you remove it while closed, then hook it up backwards, as it may happen when the outlet is removed for some work and reinstalled, it will remain closed.

The likelihood of that happening is fairly high. The old one feeds in from the bottom, then out the top. The new one feeds in from the top and out the bottom. The difference is a recipe for error.

First off, just a manner of semantics, you have a feeder not a service.

As far as the GFCI tripping. I would ask them, or check for yourself what is plugged in. Then unplug anything that is plugged in. Reset the GFCI, if it holds, plug one thing at a time in and see if you can catch what is tripping it. Sometimes people don't think or maybe just won't tell you the whole story. It could be as simple as a heater with a bad cord or even a faulty phone charger.

How would a faulty phone charger trip a GFCI? You'd have to have a short between pri and sec sides within the charger in addition to the charging end of cord touching something grounded.

 

[hillbilly1]

Since it was tripping originally, then mysteriously quit tripping, I would venture a guess something was turned off between the time the tripping was happening, and then not. I would further say, it probably was a light switch, and that load has a mistapped neutral or hot to the wrong circuit. Probably the HO turned that switch back on later after you left, and re-introduced the problem.

 

[Little Bill]

How would a faulty phone charger trip a GFCI? You'd have to have a short between pri and sec sides within the charger in addition to the charging end of cord touching something grounded.

I have seen them trip a GFCI. Can't explain how but know that after it was removed, no more tripping, and I did say "faulty"! They will also trip an AFCI. Whatever, my point to the OP was to check what's plugged in.

 

[ptonsparky]

A partially engaged charge cord for an Apple laptop, load end, will trip an older combination AFCI. Long before and not a dual function. Repeatable.

 

[Dell3c]

I'm agreeing w/ hillbilly1.. Noticing in first posting total (3 circuits) exiting from load center ..Might this be a (multiwire branch circuit) or circuit(s) on same grounded conductor (neutral). Possibly are you introducing stray current (or problem) onto line side neutral conductor, feeding this GFCI device?