My GFCI has gone TU

While attempting to find a power source to keep the RV battery charged, I recently learned that my outside outlets have quit working. Drag. So I started looking for other outlets that can be reached by the RV extension cord. The ones in the garage are dead too. Hmm…

I then learn about my GFCI (Ground Fault Circuit Interruptor, for those just following along) receptacle, and that my basement workshop also cannot get power.

I then read that GFCI’s are squirrelly little things which can take hiatus for the most specious of reasons. I replace the puppy.

The reset button lights the LCD for a tiny fraction of a second and I hear the treadmill try to boot up - then it fails.

I think I understand that something downstream from the GFCI has a ground fault. I replace all the other receptacles downstream from the GFCI. No workee. I then go back to the GFCI and remove the Load wires. Voila! The reset button stays reset! At least now my accomplice has power to her treadmill and the DVD player.

But that still leaves me with no power to my lair of villainy, or the batcave, or the patio. Since I can’t get power to any of them, how do I find out which one is the culprit?


  • H.

It’s been a little while since I had to troubleshoot my workshop wiring but things I’d try:

  1. Get an AC outlet tester (it’s a three-pronged widget that costs a few dollars at the hardware store. You plug it into each outlet and it will tell you if it finds open ground, reversed wires, etc). Here’s one (although it’s $18):

  1. Since the GFCI tripping cuts power to the downstream outlets you could try swapping the GFCI with the regular outlet on the first receptacle downstream, see if it trips, then swap it with #2, #3, etc. Just work your way down the line until you can isolate where the fault lies (at outlet #4, or between #2 and #3, whatever it happens to be). I’d think that the problem would be right at a box but I suppose it could be in the wall which would be a pain.

  2. Although you’ve replaced all the outlets, check the screws that hold the outlets and cover plates on. When I was wiring my garage I managed to have a screw nick the insulation of a hot wire when I closed all the boxes up following inspection. Turned the power back on and bang, short-circuit.

  3. I’m told that having one GFCI protecting a lot of outlets can lead to false tripping of the GFCI. If everything seems to be perfect, put an extra GFCI in the middle of the run and see if that helps. How many outlets are protected by the existing GFCI and approximately what is the circuit length? A 200’ run may behave differently than a 20’ run.

  4. Are you doing all of your testing with nothing plugged into the outlets? If there’s only a problem when you plug something in, that item could be the problem. See if you get the same result when you plug the (treadmill, etc) into a different outlet.

  5. I’m sure you know to do this but kill the circuit at the breaker before working on it :smiley:

Thanks, Valgard.

When I replace the GFCI with a regular outlet, will I have to unbundle the Line and Load pairs? Today is the first time I’ve replaced an outlet, though I’m a master at installing dimmer switches!

There’s been nothing plugged into anything while I’m doing the changes. I must have done about four miles of Stairmaster going into the basement to switch the breaker everytime I do something. The treadmill has been my tester in the garage because it beeps when it first gets power.

Thanks again!

The outlet tester **Valgard ** linked to won’t help if the downstream outlets only get power for two miliseconds before the GFI trips.

What I’d do is to leave the existing GFI in place. Connect the wires that were on its LOAD terminals to the LINE terminals. This makes it so the GFI only is protecting whatever’s pluged directly into it. Now, go on down the line, and replace the regular outlets with GFIs.

20 years ago, GFIs were painfully expensive things, but they have gotten cheap enough that there’s no particularly good reason to put up with playing hide-and-seek with a fault that might be nothing more than the wiring got damp from high humidity in a bathroom or a recent rain.

Don’t do that – it almost certainly violates the electrical code. GFCI’s are now required in certain locations (generally places that can get wet, like bathrooms, garages, & outdoor outlets). And for good reason – the safety of you & your family.

Leave the GFCI outlet there, and go thru the suggested procedure to find just what downstream is causing it to trip, and then fix that. You might consider replacing the downstream outlets with GFCI ones, each controlling only the single outlet and not downstream loads. That adds cost, in that you have to buy more GFCI’s (but they’re cheap nowdays), but it saves you the time & effort of searching out where the fault is – it’ll be at whichever one of the GFCI’s is still tripping.

Okay, I’ll leave the GFCI in place, and replace the others with GFCI’s, yes? Since they’re all at the ends of their various lines, do they get wired to the LINE terminals?

ok, i know this is inappropriate - but I find all this technical conversation very sexy. Is that wrong? Good luck figuring out your solution - i just love to hear guys “talk shop.”


In boxes with two sets of wires (both sets presumably attached to the plain-jane outlets) you’ll need to tie those (same colored*) wires together with wirenuts with pigtails going the LINE terminals of the GFCI; the LOAD terminals will not be used.

Not the clearest description I’ve ever given. If you have the slightest question about how to do this, go to the library and find a book with lots of pretty pictures of electrical wiring - this is one of those things that is much easier to show than to explain.

*i.e., white wires go together, black wires go together; don’t mix 'em unless you’re insurance is paid up

Let’s get a few things straight. A GFCI breaker may protect as many receptacle devices as are present on the branch circuit. A GFCI receptacle may protect up to six (6) downstream duplex receptacles.

If a GFCI is tripping, blindly replacing other devices is not only a waste of time, but also a waste of money.

Since the GFCI at the beginning has been replaced, and the downstream receptacles have also been replaced, my first question is: did you use screw terminals, or backstab connections on the downstream devices? If backstab, redo them the right way, and use screw terminals. Since you may have something flaky going on, I’d also leave all of them standing free of their respective device boxes, and see if the GFCI will reset. If so, begin installing them, one at a time, and thereby determine which one has nicked wiring or some other fault causing the trip.

Turn off the breaker, remove the LOAD wires from the GFCI, unplug anything plugged into any of the other outlets protected by the GFCI…and put a meter across each pair of the wires. Test for resistance between hot and neutral, between hot and ground and between neutral and ground. That will tell you if there are any shorts. If there are, check each outlet, disconnecting and testing until you find the short. If you don’t find any evidence of a short, you have a bad GFCI. Replace it.

Already done, per the OP.

Also, metering for a short is not necessarily instructive. If you happen to be metering a branch circuit with transformwer wired across it, such as for a doorbell, it can look like a short at DC. The advice given by dwc above is best.

I used screw terminals. Home Despot didn’t have the backstab kind which would have not only matched my GFCI, but also the three receptacles I threw away. Hey, they were cheap and I thought I could replace the lot of them easier than I could buy a meter.

We can trouble-shoot the circuit in question without replacing all the devices downstream of the GFCI.

Where is the primary GFCI located?

Is it wired properly, IOW, do you know for sure that the line comes right from the breaker and that the neutrals aren’t crossed? If it’s wired backwards (line and load reversed) it will not work. IOW, make sure the hot and neutral from the breaker go to the line of the GFCI and that the branch circuit wires go to the load.
Neutrals must be separate, no pigtails or crossing allowed.

What causes the circuit to trip? Is it the treadmill? Re-wire the GFCI to the line and load properly while everything is unplugged from the outlets downstream and see if it holds.

Does any lighting not work when the GFCI trips? If so, you may have a dimmer on that circuit which is causing the problem.

What I would do if there is a dimmer on the circuit is similar to what gotpasswords has suggested. Rewire the circuit off the load side of the GFCI and then only add GFCIs where they are needed. In the garage, basement, outside, etc. They will all be line GFCIs and not have any loads off of them. I can get you a list of locations from the code where GFCIs are required if you are confused as to where they are needed. IOW, you may have ten outlets on the circuit but only four need to be GFCIs. If you have lighting loads on the circuit also this would solve the problem of the dimmer tripping the GFCI.
Also, the treadmill might be better served if it was on its own circuit. Since you seem to be able to do some menial wiring you might be able to add an additional circuit safely.

Okay. The GFCI is in the garage. I believe that it is immediately off the main breaker box. Downstream from it are the garage receptacale (1), the basement receptable (also just one) and the external porch receptable. Each of these are two-outlet gangs with just one hot, one neutral and one ground.

None of them, apart from the GFCI in the garage, has any wires coming off of them. They all seem to be the ends of their lines.

What causes it to trip? I discovered it was tripped when I tried to power my RV from the porch outlet. This was after the sort of rains that are the only other reason Iowa gets into the news.

Nothing, but nothing, as gotten any power to those three outlets (the garage, the basement and the porch) since the GFCI tripped. I suppose I could just bypass the GFCI and connect the Line to the Load wires, but that seems like a bad idea. :rolleyes: So I’m not going to do that.

The last thing I tried was to pull all the outlets in question out of the walls, so that if there was a short-to-box I might have gotten rid of it. Nothing. Then I removed the hot wire from each outlet in turn (yes, the breaker was off). My thought was that this would tell me which of the three was shorting. Instead, it told me nothing.

So I went back and unwired the Load wires from the GFCI, until I can get back to play with it some more. I suppose I could rewire the Load wires into the GFCI and replace the other three with GFCI’s in the hope that one of them would trip. But I’m really guessing at this stage.

I suspect that somewhere in the walls there is an exposed, wet, wire connection and that I will end up paying a whole lot to an electrician to find and fix it.

Since you have identified three downstream duplex receptacles, and state that only the one in the garage at the GFCI has more than one piece of romex in the device box, this leaves two possibilities:
(1) there are four pieces of romex in the garage device box, those being one line from the panelboard, and three branches going to the listed locations, or
(2) if there aren’t four pieces of romex in the garage device box, there is a junction box somewhere else.

If you have four pieces of wire in the garage device box, try hooking up one of the branches at a time, to see if the faulty branch can be isolated. If you don’t have four in that box, I suggest you find the junction box and examine connections there.

Don’t confuse backstab with pressure screw terminals. All of the GFCIs I’ve seen lately have the pressure screws, and they make excellent contact. Backstabs are notorious for making poor contact, hence my query. My home was wired with backstabs, and I had to remake many duplex connections when I added GFCIs to bring the place up to current NEC standards.

To answer your question about what causes it to trip, a GFCI protects you by monitoring current flow on both the hot and neutral, and if they are equal, the unbalanced flow is zero, and the GFCI stays on. If the current flow on the two are not equal, that tells the GFCI that something else (possibly YOU) is completing a parallel path, and the device opens the circuit before you fry.

Okay. One last idea before I have to pay someone. Right now the Load lines are off the GFCI in the garage, which means that the GFCI itself powers things, but nothing downstream from it does.

There’s another outlet in the garage and it’s dead too. It seems to have a pair coming off the main GFCI and another pair that lead to the porch external outlets, and these two pairs are ganged and pigtailed into the garage outlet. The dead one.

The porch and the basement outlets are single-pair, ends of their lines. If I:
replace the garage, the porch and the basement unprotected outlets with GFCI’s, and;[/ul]
[ul]hook the Load wires back up to the main GFCI[/ul]
will that:
power the ones that aren’t shorted and;[/ul]
[ul]show me which one is?

If I read you right, and you’ve guessed the wire routing right, there has to be a junction box somewhere after the garage outlet you describe - perhaps between that outlet and the porch. Check the garage walls for a four-inch-square metal plate with two screws in opposite corners. That would be the junction box. These things are supposed to be accessible, but it’s always possible someone later mounted something on the wall over it. The j-box is a distribution point - one cable coming in feeds however many cables are going out.

You haven’t driven any screws into the garage wall lately, have you? If I had to guess (and, I guess I do!), I would suspect that someone drove a screw or nail into the wall sometime and happened to hit a cable.

Thanks! I’ll see if I can find it.

Okay - that’s weird. I still haven’t found that junction box, but since it’s been a day and half since the rains quit (did I say I was in Iowa?) I decided to link it up again and see what happens.

Everything works. Power to the basement, shop, porch…I think I’ll leave it alone for a while.