GFCI Keeps Tripping

The GFCI in my garage was working fine for over 10 years until a few weeks ago it began tripping every few days. Now it just keeps tripping. There are 4 pairs of GFCI protected outlets in 3 restrooms. There is nothing plugged in. When I press the reset button, it holds for a few seconds then trips. I thought the GFCI is bad so I bought a new 15amp GFCI and replaced it today but it did not resolve the problem.
I heard you can't have a ground fault if there is no current. But I have unplugged everything and it still trips. What can cause this problem?
Thanks. Jack
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X-No-Archive: Yes
Jack wrote:

That means there's a current leakage in wiring downstream of the GFCI. Call an electrician.
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Jack wrote:

The fault could be with wiring in the wall.
--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math
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If you know how to change the GFI do that first. They often go bad in 10 years.

are
plugged
today
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Learn to read, Jack....he's already replaced it.

weeks
trips.
have
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My signature is Art, not Jack. I missed the change out but the new one could be bad too.

There
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I am wondering exactly how many GFIs he has, and which normal plugs are protected by GFIs in other places. In other words, what does "4 pairs of GFCI protected outlets in 3 restrooms" mean? Very possibly there are some receptacles that have water or other residue in them causing the GFI that feeds them to trip. Look in, and disconnect for testing, the receptacles that are protected by the GFI that is tripping. It is unlikely that the wire is bad unless it is knob and tube or cloth insulation. The problem would be in a box, its receptacle, or something plugged in. Are there any bathroom *lights* that are controlled by the GFI? --Phil
Art wrote:

--
Phil Munro Dept of Electrical & Computer Engin
mailto: snipped-for-privacy@cc.ysu.edu Youngstown State University
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Next step is to remove all the downstream outlets from the wall and see if there are any obvious problems, like connections that have come loose, cracked/broken outlets, etc. After that, you need to follow the wiring downstream from the GFCI to the first protected outlet and try disconnecting eveything after that by removing the outgoing wires. Then see if it still trips. Eventually, you should be able to determine which outlet or run is the culprit.
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I assume by "4 pairs of GFCI protected outlets", you have four individual GFCIs. If not (ie: only _one_ GFCI), then the following becomes somewhat easier, and you can ignore all the series/parallel stuff.
[Thinking more on this, it probably is a single GFCI, with a fault downstream of it.]
Are the GFCI's in series? That is, except for the last one in the series, tripping the GFCI (by the test button) will cause more than one pair of outlets to go dead.
If they're in series, your problem would be at the GFCI that's tripping, or one of them "downstream".
If they're not in series, ie: each GFCI trip only controls itself (watch out for other things you don't notice on the same circuit), then the fault would be in the receptacle box.
["downstream" outlets are connected to via the "load" terminals on each GFCI.] [Make sure you have line/load connections right. If you reverse one or both wires w.r.t. line/load, wierd things can happen.]

Knowing you've replaced the one that's tripping suggests that it's not the GFCI at fault. Unless you wired it wrong.
So onto circuit diagnosis:
Make sure you know exactly which devices are controlled by the GFCI that's tripping. You may have devices you're not aware of "downstream" of individual GFCIs. Ie: an outdoor light that's rusting out or has had some wires come loose.
A GFCI will often detect a neutral wire touching a ground wire, so they can trip even if nothing is plugged in.
Condensation, moisture leakage or corrosion can produce a conductivity pathway between a hot or neutral and ground and trip a GFCI, even if the circuit doesn't have anything plugged in.
If you have GFCIs in series, a defective "downstream one" may trip an "upstream one".
Killing the power on the circuit and then opening up each box in turn looking for moisture/corrosion or loose/stray ground wires will probably find the problem. If not, you'll have to start isolating receptacles to see which circuit section contains the fault.
The sort of really obnoxious-to-find scenario is something like someone hung something on the wall, and a nail punctured a cable and shorted a neutral to a ground.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
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I had the same problem. Turned out an exterior outlet had deteriorated.
You must have a bad connection somewhere. Disconnect the last outlet and see if you still have the problem. Then disconnect the next one, etc. It is a pita, but it is the only way to isolate the problem, and is how I found mine.
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found
Thank you all for the suggestions. Sorry I confused Phil by "4 pairs of GFCI protected outlets in 3 restrooms". To clearify that, I have only one GFCI in my house and it is in the gagurage. There are 4 pair of receptacles (each pair share the same cover plate) in the restrooms that have "GFCI protected" sticker. I did verify that only these receptacles have no power when the GFCI trips. All other lights and receptacles in the house are working fine without interruption. Again, the GFCI trips in a couple of seconds whenever I press the red "reset" button while nothing is plugged. Currently it is connected to a new GFCI and that did not make any difference.
I didn't know receptacle can go bad. I'll follow Chet and Toller's suggestions tonight to remove the receptacles one unit at a time to decide which one is bad. Thanks again!
-jack
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Didn;t confuse me, the way you described it is how they are supposed to be installed. One GFCI outlet can protect not only itself, but other regular outlets connected to it. It does create a mystery for some homeowners who don't realize it. The GFCI in the lead outlet trips, power goes out somewhere else, they look at the circuit breaker in the basement, it's not tripped and they can't figure out what happened. It's especiall confusing when the GFCI can be in the garage, yet other outlets be in bathroom, outside, etc.
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Remove the GFCI and then use a digital multimeter and check out the circuits.
wrote:

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Jack wrote:

Thanks. I am wondering if by a "pair" you mean a single "duplex" receptacle in a box. A duplex recpt has two outlets on it. It seems unusual to have *four* pairs of duplex receptacles. If your box sizes allow it, I always prefer a GFI in *each* protected location. You could do that by changing the wiring at the garage GFI so that the feed to the others is a non-protected power feed. This solves the problem of knowing where to look when a GFI trips! And since the cost is usually about $8 or so, it is not very expensive to do it. --Phil
--
Phil Munro Dept of Electrical & Computer Engin
mailto: snipped-for-privacy@cc.ysu.edu Youngstown State University
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Keep in mind, in the 70's when GFCIs were 1st required, they were VERY expensive. Hence the daisy-chaining.
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in article snipped-for-privacy@news.teranews.com, Jack at coocoonut@$$hotmail.com wrote on 7/8/04 12:32 AM:

A ground fault you cannot unplug.
Bill
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