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GFCI driving me nuts !

4K views 78 replies 12 participants last post by  Yodaman 
#1 ·
my gfci tripped when i plugged my blender in it and the blade got stuck as i had stuffed too much stuff in it. thats when my nightmare started. I replaced the GFC I and was careful about the Load vs line problem ... and it did not work .. thinking that I had a bad GFCI outlet I bought another one and tried that and that did not work either ... I went in for yet another GFCI outlet and this one worked ... but only for a day and the outlet has gone dead again ... I have tested the circuit with my voltmeter ... it's showing me 122V between the hot wire and neutral as well as between the hot wire and ground ... The only thing I have plugged in there is my microwave ... The microwave is fine because I have been plugging it into another GFCI outlet nearby and it has been working fine for over a week ... any ideas what am i doing wrong ?
 
#16 ·
my gfci tripped when i plugged my blender in it and the blade got stuck as i had stuffed too much stuff in it. thats when my nightmare started. I replaced the GFC I and was careful about the Load vs line problem ... and it did not work .. thinking that I had a bad GFCI outlet I bought another one and tried that and that did not work either ... I went in for yet another GFCI outlet and this one worked ... but only for a day and the outlet has gone dead again ... I have tested the circuit with my voltmeter ... it's showing me 122V between the hot wire and neutral as well as between the hot wire and ground ... The only thing I have plugged in there is my microwave ... The microwave is fine because I have been plugging it into another GFCI outlet nearby and it has been working fine for over a week ... any ideas what am i doing wrong ?
A GFCI test button will also not work if there is no ground.

What type of meter are you using?



Remove the GFCI and
measure from the hot to a neutral, ground and hot of another GFCI (GFCI removed)
measure from the neutral to a neutral, ground and hot of another GFCI (GFCI removed)
measure from the Ground to a neutral, ground and hot of another GFCI (GFCI removed)


That should tell you if you have a good neutral, hot and ground. It is a starting point in trouble shooting this issue.
BRIA.... I'm not sure what you meant..... I think he did that.
 
#28 ·
ok - i seem to have fixed the issue - at least for now. the switch is working now. my best guess on what went wrong is this - there is quite a bit of wire inside the box a little more than what I have usually seen in other switches .... this meant that the wires had to be coiled and pushed back into the box. And since the GFCI also outlet takes more space than a normal switch -- I am assuming that the naked ground wire had been touching the neutral point of the GFCI everytime I was pushing the GFCI in the box and against the coiled wires in the box --- it was perhaps sheer coincidence that the same thing happened every time I tried to replace the GFCI - except for the one time when it worked for a day, but eventually maybe due to the 'memory' or heat the ground wire started touching the neutral again after a day- I have no other explanation ... :) ... will let you know if it stops working - but thanks everyone esp MTN and Bria - i thought of this only because you were pointing towards the wires being short some where or the other .... i'm downgrading my skills from beginner level to idiot :)
 
#32 · (Edited)
ok - i seem to have fixed the issue - at least for now. the switch is working now. my best guess on what went wrong is this - there is quite a bit of wire inside the box a little more than what I have usually seen in other switches .... this meant that the wires had to be coiled and pushed back into the box. And since the GFCI also outlet takes more space than a normal switch -- I am assuming that the naked ground wire had been touching the neutral point of the GFCI everytime I was pushing the GFCI in the box and against the coiled wires in the box --- it was perhaps sheer coincidence that the same thing happened every time I tried to replace the GFCI - except for the one time when it worked for a day, but eventually maybe due to the 'memory' or heat the ground wire started touching the neutral again after a day- I have no other explanation ... :) ... will let you know if it stops working - but thanks everyone esp MTN and Bria - i thought of this only because you were pointing towards the wires being short some where or the other .... i'm downgrading my skills from beginner level to idiot :)
Amit... don't be downgrading your skills to idiot... upgrade to learning more new stuff. Actually, you tested and analysed things very well.

(Don't want to rain on a sunny day, but I still think you have/had a bad/poor/loose splice in the box. It may have justled back to a good connection and may function fine forever now,,,,, but I don't think a neutral ground contact would not stop your GFI from resetting (and immediately tripping).,,, this is to the best of my knowledge,,, I'm not intimately familiar with the electronics in a GFI.

Our previous thought of a neutral/ground short was before we knew that the GFI would not reset momentarially.

But happy you are up and running now....

Good going...
 
#35 ·
Amit.... We x-posted when I thought you had it working.

Now I find more possibly indictive evidence you have a week/tentative /poor splice/connection somewhere.

When you have a weak tentative connection and under load (microwave) the connection/splice heats up and can break.

The fact that it appears you have no power to the gfi recep (no light and will not reset momentarily) indicates to me the liklyhood of a poor splice (wire nut) and especially with a crowded box, seems to me that that would be the likely location. (You never answered me whether your GFI feed is off a pigtail)

I think BRI suggested putting in a regular receptical... simple enough, and then we'll have a little more indication if you have a loss of power, or a ground fault.

If the regular recep fails... we will know you have a loss of power. If it works, we will still not know for certain the issue.

Good luck
 
#49 ·
Here I thought this one was solved.

I also see the GFCI is being used in isolation, i.e. there are no downstream outlets running off of the load side of the GFCI.

A GFCI will not reset due to a few conditions.

1) no power, without power the reset cannot latch
2) fault condition,
(a) ground fault exists (inbalance between hot and neutral currents)
(b) neutral and ground are shorted (GFCI detects this as a fault and trips
(c) neutral corruption on load neutral (when a load side neutral is
inadvertently combined with other circuit neutrals in a downstream box

Since yours seems to be an intermittent issue it seems to suggest your wiring is correct except maybe you have some loose connections somewhere that are arcing under load.

It is possible (but highly unlikely) your microwave is creating noise on the AC lines that is playing havoc in the GFCI circuitry but I think this is a long shot as GFCI circuits are very mature and noise immune. Regardless your problems seems to persist even when oven is off.

So I'd look for a loose wirenut upstream or maybe a fractured wire beneath the insulation at a sharp bend. If the box is metal maybe someone cranked down on the NM cable clamp too hard such that it has pinched through the insulation to the conductor. If it was on the white line that would create a neutral to ground fault but no arcing.
 
#50 ·
thanks Curious for the explanation - its helps me understand gfc better. yes, most people are pointing to some fault in wire/ connections... will put a regular outlet and see -- it will at least tell me if it an 'arc' / spliced wire/ loose wire nut related issue on hot or neutral
 
#54 ·
OK so I checked the war teach between neutral and ground and hot within this OK and with another outlet ... here are the results I'm getting ... I took a video while doing these tests but I realize that this site doesn't allow us to upload videos

A. within the same outlet:
hot to neutral 82V
hot to ground 122V
ground to neutral 29V

B. between this outlet and the other one
1. hot of other and neutral of this 142V
2. neutral of other and hot of this 122V
3. neutral of other and neutral of this 29V

not sure whats going on
 
#57 ·
also after I put the outlet back into the wall, I was able to reset it - so I measured the workdays again this time in the outlet - now it is showing me 122V between neutral and hot and negligible between neutral and ground. The only thing I did in between was that I had switched off the main breaker off and then on in order to put the outlet back
 
#62 ·
also after I put the outlet back into the wall, I was able to reset it - so I measured the workdays again this time in the outlet - now it is showing me 122V between neutral and hot and negligible between neutral and ground. The only thing I did in between was that I had switched off the main breaker off and then on in order to put the outlet back
Are you sure that you did not turn on or turn off anything (changing the draw) on either of these two circuits while you went to turn off the breaker.
 
#58 ·
AMIT..... Could you reread your post.... and try to explain exactly what you did in this test.......

If I understand at all.... you had tested this circuit previously and it read fine.

Do you know what a MWBC (multi wire branch circuit) is and is one involved here.
 
#61 ·
yes MTN - i had tested it before and it was fine --- it is fine now as well after i have put the outlet back

i am now beginning to think that the problem is in one of the other appliances i have on this circuit - my washer dryer and dishwasher ... next time the gfci fails, i will unplug them one by one to see if anything changes
 
#64 · (Edited)
There is nothing that can occur in the upstream appliances that would cause you to have an intermittent voltage, or no voltage on the last outlet. It is more likely that in one of the upstream devices you have a poor connection, and it revealed itself when your blender locked up and overloaded the circuit.

Based on your test reading finding voltage between the ground and neutral, it's a fair bet that a neutral wire in an upstream box is poorly spliced, or backstabbed into the receptacle.
 
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