Ground Fault Outlet - Tripping

Hello all.
I'm having a weird problem with the ground fault outlet (3 prong) in my garage. It works fine if I have something plugged into the top outlet. When I plug something into the bottom outlet, it trips the breaker. I have replaced it with a new one and it's doing the same thing.
Any suggestions/tips?
Thanks in advance.
Mike
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mike snipped-for-privacy@yahoo.com (Mike McCormick) wrote:

OK, you plug something into the bottom outlet and the GFCI trips. Are you saying that if you reset the GFCI and then plug the *same* thing into the top outlet, it does *not* trip? Even after replacing the GFCI?
-- Doug Miller (alphageek at milmac dot com)
How come we choose from just two people to run for president and 50 for Miss America?
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Mike McCormick wrote:

If you're considering a new career as a tech writer, keep your day job. <G>
*********************************************************
Is the ground fault breaker built into that outlet or is it in the breaker panel?
Whether or not it's in the panel, how many wires connect to the terminals on the outlet in the garage?
When you plug "something" into the bottom outlet, have you also left "something" plugged into the top outlet?
What are the "something(s)", and do they have two wire or 3 wire cord sets on them?
*********************************************************
Jeff
--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"My luck is so bad that if I bought a cemetery, people would stop dying."
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Mike McCormick wrote:

It is not clear what you mean. Do you mean that plugging appliance A into the top works but pluggin appliance A into the bottom trips the circuit. Or do you mean that plugging A into the top is ok and keeping A plugged in and then pluggin B into the bottom trips the circuit?
How many wires entering the box? and how are they hooked up. It sounds like either plugging something into the bottom causes a short in the box, or something downstream is wired wrong.
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mike snipped-for-privacy@yahoo.com (Mike McCormick) wrote in message

Sorry I wasn't more descriptive. :-)
The outlet is a GFCI outlet.
I can plug something/anything (radio/freeezer for example) into the top outlet and things work OK. I can unplug the same thing from the top outlet and plug into the bottom outlet (with nothing plugged into the top) and it trips the GFCI outlet and kicks the breaker off in the breaker panel. I have replaced the GFCI outlet and the new one does the same thing.
I have tried plugging in two prong as well as three prong devices to this outlet. Same results - works in top outlet, trips GFCI and breaker if plugged into bottom outlet.
There are two sets of wires that connect to the terminals. One set of three wires for top outlet. One set of three wires for bottom outlet. I have confirmed that the wires are connected correctly (according to the wire colors and the bottom outlet is connected the same as the top outlet).
Thanks again for any help/tips.
Mike
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Sounds as if there is a problem with the wires on the bottom. They may be correct in the box, but may be connected wrong somewhere upstream.
Check them to be sure that the black or red wire is really the "Hot" wire and that the ground is really grounded.
-Jack
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Up to this point I'd say that the GFCI is defective. Having the breaker trip indicates that the defect is _severe_ (high amperage short). Ie: something mechanically wrong with the bottom outlet causing internal conductors to short.

Yes, and that's where this gets very wierd.

"Properly" wired, I'd _expect_ to see five wires in total:
1) two blacks, one connected to "line" (feed in), other to "load" (feed out). 2) two whites, one connected to "line" (feed in), other to "load" (feed out). 3) One bare wire (usually from "feed" cable), connected to box screw, outlet green screw and wirenut to feed thru to bare wire on "feed out" cable.
GFCI's (like ordinary receptacles) usually only have one ground screw, because they do not want to encourage you to use the GFCI's ground terminals as the connection point for downstream wiring. Ie: the outlet ground should effectively be a pigtail off a wirenut connecting all the grounds together (and to the box).

You know what I think is happening? There is an intermittent short _in_ the box. Most likely damaged insulation on one of the cables (as it goes thru the box clamp), or possibly exposed conductor on a wirenut, most likely in the bottom of the outlet box.
When pressure is applied on the bottom of the outlet (bottom half of the box), it's enough to make the exposed/damaged conductors contact each other. The geometry is such that this doesn't happen when pressure is applied to the top half.
I'd kill the breaker, remove the outlet, loosen the clamps, and very carefully inspect everything. Remediation is tricky, depends on exactly what is wrong.

Also worth doing.
Does the "test" button work (when nothing plugged in and breaker turned on?)
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Now all the while I was thinking there are 2 duplex receptacles involved. An "upper" one (maybe near the panel) and a "lower" one located elsewhere in the garage.
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Mike, A word of warning ... do NOT plug your freezer into a GFCI outlet. When the freezer kicks on it may trip the GFCI leaving you with a freezer full of spoiled food. Same thing applies to a refrigerator. You should run a dedicated (non-GFCI) outlet to the garage for the freezer.
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This is a multi-part message in MIME format. --------------040904020309000706060406 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit
Mike McCormick wrote:

Shut off the power to that outlet at the breaker panel and pull that outlet out of its box so that it's hanging on it's wires with none of the screw contacts anywhere near touching anything else.
Turn the power back on again.
Put on a pair of heavy rubber gloves, and try your pluging in tests again. BE CAREFULL!!!
If you can now plug into the bottom outlet without tripping the GFI, then shut off the power and look at things carefully to see if you can see whether any uninsulated parts of any of the wires could be touching any other uninsulated things (like a metal outlet box or the bare ground wires) when it's reinstalled and you push in on the outlet's lower end. If that's what's doing it, you should be able to figure out what to do to correct it.
If the GFI still trips when it's free of the box, then shut off the power and disconnect the wires coming from the "out" screws on that receptical. (They are feeding another receptical or device protected by that GFI.) Try your tests again.
If that doesn't do it, either you're either accidently misleading us with your descriptions or you've got a poltergeist in your house. <G>
Jeff
--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"My luck is so bad that if I bought a cemetery, people would stop dying."
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The question is, where are the two sets of wires connecting to the GFCI coming from? One possibility is that the bottom wire feeds from the top (hot) one and then goes to another outlet somewhere. That other (or others) outlet(s) might be the cause of the tripping. Another possibility is that both wires connecting to the GFCI are hot. In that case, there might be a problem with the connection of the bottom wire to your breaker box (if coming directly from the box) or with outlets or devices upstream drawing too much power or being faulty. Use an outlet tester to check whether turning off the breaker for the top plug also cuts power to the bottom one or examine the GFCI to see if the connecting tabs have been removed. If the GFCI only has one hot feed (most likely) try to disconnect the bottom wires and then test the bottom plug. If it doesn't trip it's a good indication that the problem is downstream. My guess is that there is a ground fault downstream. The GFCI is not causing the problem, it's just showing it to you. Unless you find the problem easily I would call a pro. You might have a potentially dangerous situation somewhere on that line. Good luck, Stephan.
in article snipped-for-privacy@corp.supernews.com, Jeff Wisnia at snipped-for-privacy@conversent.net wrote on 2/11/04 5:21 PM:

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No, this is all misleading.
The OP's problem is that a device plugged into the upper outlet works fine, and the same device plugged into the lower outlet causes the GFCI _and_ breaker to trip.
The two outlets on a GFCI are internally connected together (like on an ordinary outlet with uncut jumpers), therefore, it shouldn't matter which outlet is being used, it should behave _identically_.
No matter which wire is connected to which terminal, it couldn't possibly cause this problem, especially if it ever worked in the past.
There are only two possibilities:
1) the GFCI itself is defective. But the OP has replaced it, and the problem is still happening, so, unless he's managed to get two successive GFCI's with exactly the same marginal/unusual defect, _extremely_ unlikely.
2) The act of pushing in on the bottom outlet causes a hot-ground [+] short in the wiring inside the box (load side of the GFCI)[+], whereas pushing on the top outlet doesn't. This suggests a bit of bare hot wire near a ground that makes contact with the ground when the box or wiring is flexed by pushing on the bottom half of the GFCI. I'd first concentrate on anything visible (like bare hot wire at a wirenut or damaged insulation touching the ground wire, box, or GFCI mounting strap), and then check for damaged cable under the box clamp[s]. I'd guess the latter, but do it step at a time so you can _identify_ what's causing it. I hate things magically starting to work without proving a reason for it.
[+] hot-ground short because a hot-neutral short shouldn't trip the GFCI, only the breaker. Not a neutral-ground short, because that would be exceedingly unlikely to blow the breaker. Load side because a short on the line side shouldn't trip the GFCI either. But, at the ampere levels implied by a breaker trip, all bets are off - it could be either hot.
--
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It's not just anyone who gets a Starship Cruiser class named after them.
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