GFI question??

[skeletonizer]

I was on my way out the door tonight and noticed that one of my GFI's had tripped. It is on a string of convenience outlets with one Liftmaster opener and it's light on the last outlet.

I reset the GFI and after about 3 seconds it tripped again. I unplugged everything on the circuit and reset the GFI again, same thing, 3 seconds and it tripped.

The breaker never tripped.

As I said I was on the way out the door so I just shut the breaker off.

I guess my plan for the morning is to change out the GFI and see if a different one will stay closed unless anyone has any other suggestions???

Can GFI's just go bad and if so is this the typical symptom?

All the outlets downstream are pigtailed with the grounds twisted and crimped.

 

[Gary S]

Yes, GFIs can just go bad. GFIs have electronics in them and anything with electronics can just go bad anytime it wants.
I agree that the first step is to try a new GFI. If the new one acts the same, you have a problem on the circuit. If replacing the GFI fixes the problem, you simply had failed electronics which we see everyday.

 

[skeletonizer]

The plot thickens.

I swapped out the GFI and it tripped.

So one by one I pulled out the 8 outlets on that circuit starting closest to the GFI. I left them connected and checked to make sure they were secure and reset the GFI after each one.

The last outlet on the circuit appeared to have the ground wire pretty far over on the hot side of the box when I pulled it out and when I reset the GFI it stayed closed.

I thought that I had found the problem but being a skeptic I left all the outlets hanging out of the boxes and temporarily moved on to another project. After a half hour or so passed I heard that damn click as it tripped. I reset it and it went almost a minute and popped again.

During the hour that it stayed closed I ran my circular saw on each outlet just to check and they all worked fine.

WTF?

What is my next step?

Why the delay?

If I had a short wouldn't it pop right away?

 

[ghnl]

When you pulled out all the outlets did you check that all connections were snug? My undertanding (limited to the smoke theory of electricity...) is that the GFI constantly compares the neutral vs the ground. Any discrepency (loose neutral or ground wire?) can trip the GFI.

 

[porschedude996TT]

When you pulled out all the outlets did you check that all connections were snug? My undertanding (limited to the smoke theory of electricity...) is that the GFI constantly compares the neutral vs the ground. Any discrepency (loose neutral or ground wire?) can trip the GFI.

It compares current from the line and the neutral. If there is more current going maybe to ground or thru someone who is holding a defective device then it will trip. It needs some dissimilar current value running thru it before it normally trips. If the GFI unit is bad then it will trip all on its own.

 

[Charles (in GA)]

When you pulled out all the outlets did you check that all connections were snug? My undertanding (limited to the smoke theory of electricity...) is that the GFI constantly compares the neutral vs the ground. Any discrepency (loose neutral or ground wire?) can trip the GFI.

The Line (or hot) and the neutral, are monitored by the GFCI. The ground is in no way monitored, interrupted or otherwise controlled by the GFCI. You do not even need a ground wire hooked to the GFCI for it to function.

Charles

 

[ghnl]

OK, I stand corrected. I knew it 'monitored' something...

 

[jdaallen]

You can buy an inexpensive circuit tester at Depot or Lowes that plugs into each outlet and tells you if that outlet is wired correctly. It also has a CFCI button on it to test the GFCI itself.

 

[Torque1st]

Are any of the outlets or wiring exposed to moisture or temperature changes that could cause moisture to condense on any wiring or outlet devices? A thin film of moisture with the addition of salts from finger prints can conduct electricity.

 

[skeletonizer]

The recent cold snap has caused some condensation inside my shop. All the outlets are on the outside walls except for the GFI itself. The last box on the run is in a corner high on the wall (for an opener) and I did see a little condensation on the ground wire in there. If condensation is the culprit why only one circuit? I have three GFI protected circuits that are all nearly identical and only this one is giving me trouble.

 

[tfi racing]

How old is the work and what wiring method was used?If NMD,check all the clamps in the back of the boxes,if the cable is squeezed too tight it could cause the GFI to trip.The next step is to open up the pigtails at each receptacle,starting with the one furthest away to try and isolate where the problem may be.Puzzlers like this are never any fun,but there is white to ground continuity somewhere.

 

[skeletonizer]

Well I'm leaning to a condensation problem. When I went into the shop today another GFI was tripped. This sloppy weathe during the day with single digits at night is messing with things. If I could get my damn cousin to hooke up my in floor I think I'll be OK. It's like 45 in there now. This is my first time with any real experience using GFI's. I had no idea they were that touchy. The system has been on since early May without a hitch so the only change has been the weather.

 

[Torque1st]

Water + electricity ==

 

[smedly]

I'd check the ground.
Had a similar experience- I isolated everything I could think of then went into the box and gave the screw holding the neural wire another 1/2 turn and all was well.