Another GFCI issue

[K8MHZ]

This job is about a 100 mile round trip, so I am looking for some valuable input. I would like to solve this issue in one trip as I don't plan to charge.

Here is the deal: No room for a GFCI outlet serving counter-top. Installed GFCI breaker instead. Breaker trips from time to time. There seems to be no pattern and it is assumed that it is a ground fault problem as no tripping problem occurred prior to GFCI installation.

The 'GC' is the HO's sister. GC says that there are no other outlets on the breaker except the counter-top. GFCI trips even when all loads (according to GC) are removed from circuit.

I have already tried to verify the problem but could not, as during the last several hour visit the GFCI never tripped once.

So......

Do I use the shotgun approach and replace the GFCI breaker based upon suspicion alone? If there were know issues with the breakers I would not hesitate to use that approach. If that approach is wrong, I won't know until I am back home and another visit will be required.

Do I trust the GC that there are no other outlets and fire up the ol' megger? What if he is wrong and I cook something? Some electronics go into a sleep mode that won't present a visible reading on an ohmeter, thus rendering them 'invisible' to the first step of conductor testing. I am always hesitant to do insulation tests on existing structures, especially older ones.

I would much rather figure out a way to actually verify the problem. I suspect that something is causing a perfectly good breaker to trip and I am not getting an accurate condition report from the GC.

What would be the first thing to look for in my case?

As far as I can see, there is no damage to the Romex which appears to be a very short run from the panel straight up to the outlet box. The box is also used as a J box for a lighting circuit and there is a switch for that circuit in the same box. I have pulled the receptacle and re-positioned the wires to no avail.

If this project was close by I wouldn't even bother you all with my questions. I know I can figure it out, it's just that since I am dealing with an intermittent problem I likely can't do it in one visit.

The GC just wants to put the original breaker (non-GFCI) back in service. Obviously, I declined and am dedicated to solving the problem correctly.

Any insight or info will be useful, thanks!

 

[magictolight.com]

I think I would replace the breaker, verify that their is no continuity between the grounding and the grounded conductor at the receptacle box, and if it is possible, without to much difficulty replace the romex between the wall box and the breaker panel. A 100 mile round trip would be well worth pulling out all the stops.

 

[celtic]

Megger the circuit.

 

[K8MHZ]

Megger the circuit.

OK, so let's just put away my apprehensions about doing destructive testing on older, existing wiring.

Since the problem is intermittent, the fault that causes it probably is, too, and likely won't show up during testing when I am there (and it isn't).

Also, where do I draw the line? If I only get 1/2 meg, which would fail an insulation test, how do I know the reading is related to the problem which only takes 24,000 ohms to trip the breaker?

I probably will test the cable when I do get there, but failing an insulation test does not automatically indicate problem solved.

 

[K8MHZ]

I think I would replace the breaker, verify that their is no continuity between the grounding and the grounded conductor at the receptacle box, and if it is possible, without to much difficulty replace the romex between the wall box and the breaker panel. A 100 mile round trip would be well worth pulling out all the stops.

I'll tell you what, if replacing the cable would have been easy I would have already done it. I really don't want to go through that on a guess.

More food for thought.

After having asked several times not once has anyone been able to cite the exact time the breaker tripped. It was just 'noticed' after the fact.

I may let HO borrow a UPS I have the beeps the instant it loses power. That would be a sure indication if the power loss (caused by the fault tripping the GFCI) was related to some other incident or the use of some device.

 

[growler]

I'll tell you what, if replacing the cable would have been easy I would have already done it. I really don't want to go through that on a guess.

I can understand not wanting to replace the cable but I believe I would trace the circuit and see where it goes.

I had one that was kind of odd. It was attached to and exterior receptacle that was hidden behind the hedges and would trip when the sprinkler system came on and soaked it with water. This was before the in-use cover requirements. All homes don't have those even today.

 

[growler]

Megger the circuit.

Mark Shunk lives on, at least in memory. :grin:

 

[wireguru]

this is one of those times where you can never trust the HO.
"There was nothing on and connected, it just tripped on its own." "Oh I always wash my toaster with it plugged in. It never tripped before (you installed the GFI)"

Take all their countertop stuff and plug it in and see if you can get the gfi to trip.

 

[Sierrasparky]

Mark Shunk lives on, at least in memory. :grin:

Boy he's not even here and he still get's blasted!

 

[gar]

090910-1214 EST

K8MHZ:

Is that actually your call sign, and did it occur by happenstance?

The receptacle box also being a junction box might be the source of the problem, and originate from the light circuit.

You did not mention the brand of the GFCI breaker.

If you have a #2 or larger motor starter, or a standard 8 ft Slimline fixture, then these can be used as transient generators by rapidly cycling them on and off. I just wiggle a plug in a socket. You might introduce transients close to the breaker and see if this will cause a trip. I believe I did this test on the Leviton GFCI that I have discussed elsewhere and could not trip that device.

You could replace the current GFCI breaker with a standard breaker. From this breaker go to a box near the main panel, install a Leviton 7899 GFCI receptacle, now connect your circuit to the output of the Leviton. Thus, the Leviton becomes the GFCI for your problem circuit. This suggestion is only based on my impression of the Leviton from a limited analysis of its operation. I do not have any field experience with the Leviton.

To know whether anything else is on your troubled circuit disable power from the circuit, connect a signal generator of some sort, and trace the circuit path and see if there are any other outlets or parallel paths. If nothing else, then do the high voltage leakage tests.

Is anything connected to the counter top receptacle when tripping occurs? If so what is the device?

.

 

[danickstr]

I would put an extension cord in the area and kill the circuit until we find out if anything else in the house is not working. If after a few days everything works, then megger it.

 

[LarryFine]

Mark Shunk lives on, at least in memory. :grin:

Boy he's not even here and he still get's blasted!

That was a blast to you? I saw it as complimentary.

 

[K8MHZ]

I can understand not wanting to replace the cable but I believe I would trace the circuit and see where it goes.

I had one that was kind of odd. It was attached to and exterior receptacle that was hidden behind the hedges and would trip when the sprinkler system came on and soaked it with water. This was before the in-use cover requirements. All homes don't have those even today.

This is what I am hoping to find out by the use of the UPS with the outage alarm. There has to be some sort of pattern, I am nearly sure of that.

 

[K8MHZ]

this is one of those times where you can never trust the HO.
"There was nothing on and connected, it just tripped on its own." "Oh I always wash my toaster with it plugged in. It never tripped before (you installed the GFI)"

Take all their countertop stuff and plug it in and see if you can get the gfi to trip.

Fortunately the HO is not pressuring me to make the repair as the only thing she uses the outlet for is a night light. The breaker trips with or without the light plugged in and as far as she can tell nothing else is affected.

The other counter-top receptacles are on different circuits and have GFCI receptacles.

And, yeah, I take everything not only HO's tell me with a grain of salt, but I scrutinize the GC's stories as well.

 

[K8MHZ]

090910-1214 EST

K8MHZ:

Is that actually your call sign, and did it occur by happenstance?

The receptacle box also being a junction box might be the source of the problem, and originate from the light circuit.

You did not mention the brand of the GFCI breaker.

If you have a #2 or larger motor starter, or a standard 8 ft Slimline fixture, then these can be used as transient generators by rapidly cycling them on and off. I just wiggle a plug in a socket. You might introduce transients close to the breaker and see if this will cause a trip. I believe I did this test on the Leviton GFCI that I have discussed elsewhere and could not trip that device.

You could replace the current GFCI breaker with a standard breaker. From this breaker go to a box near the main panel, install a Leviton 7899 GFCI receptacle, now connect your circuit to the output of the Leviton. Thus, the Leviton becomes the GFCI for your problem circuit. This suggestion is only based on my impression of the Leviton from a limited analysis of its operation. I do not have any field experience with the Leviton.

To know whether anything else is on your troubled circuit disable power from the circuit, connect a signal generator of some sort, and trace the circuit path and see if there are any other outlets or parallel paths. If nothing else, then do the high voltage leakage tests.

Is anything connected to the counter top receptacle when tripping occurs? If so what is the device?

.

Yes, K8MHZ is my actual call sign. It is a vanity call. Not to far from me is Brian, N8MHZ. His call was assigned. I didn't know of his existence until some time after I got my new call sign. He was hiking through the dunes and when he transmitted on the local repeater I thought I was hearing things. I wasn't, I answered his call and we had a great chat and a couple more after that.

Back to the program already in progress....

Great advice about installing a Leviton dead front in place of the breaker. In fact, making a test rig out of a dead front protector and scabbing it in wouldn't be a bad idea, either, as swapping the breaker for another one of the same may not solve the problem due to a batch wide QC problem. I have been bit by that in the past.

As far as I can tell, the breaker tripped with no devices connected.

 

[growler]

No room for a GFCI outlet serving counter-top. Installed GFCI breaker instead.
The box is also used as a J box for a lighting circuit and there is a switch for that circuit in the same box.

Is this a double gange box ( plastic )or a switch/receptacle combo in a single gange box? The only bouble ganges that I can think of that are so shallow that it's hard to get a GFCI receptacle into are those gangable cut in boxes ( metal type ) or wiremold boxes ( also metal). If this is the case you may want to check where the cable enters the box for damage. When you try to ram a lot in small metal boxes it's real easy to nick a neutral or something that many only show up at times . If it's a cut in box ( old works) and madison clips then things can wiggle around a bit when appliances are plugged in.

 

[hurk27]

Here's a little food for thought, I had one case where the neutral was grounding out and it wouldn't always cause it to trip, another time it was the neutrals of another circuit got inadvertently connected together with the GFCI neutral, but this other circuit was rarely used so it wouldn't trip all the time. try lifting the neutral for this circuit and see if it still has continuity to the neutral bar, if it does you have either a grounded neutral or a bootlegged neutral.

 

[electricalperson]

i would megger the circuit at 1kv. make sure you remove ALL LOADS lightbulbs, appliances all other electronic circuits too. megger at a low volt probably 50 or 100v first to make sure nothing is attached. megger neutral to ground hot to ground. its also possible you might have neutrals tied together in switch boxes with more than one circuit

 

[gndrod]

question or 2

question or 2

K8MHZ,
I probably missed it but did you mention the GFCI and panel brand yet? OCPD Amp size? Length of BC run. Over 100 ft.? Any other BC parallel cabling together in that run? Type of lamping (ballasted?) from the switch circuit in same box? Neutrals tied together?

It is bizarre that this is the only outlet from the panel OCPD for a receptacle and lighting circuit and not a MWBC. If this is a kitchen counter outlet was it originally for the lighting? Or was the receptacle combined later with the light circuit? I interpret 2 BC's in the same box. Is this correct or am I in need of more info and most likely not on the same page yet. Tx, rbj

 

[K8MHZ]

K8MHZ,
I probably missed it but did you mention the GFCI and panel brand yet? OCPD Amp size? Length of BC run. Over 100 ft.? Any other BC parallel cabling together in that run? Type of lamping (ballasted?) from the switch circuit in same box? Neutrals tied together?

It is bizarre that this is the only outlet from the panel OCPD for a receptacle and lighting circuit and not a MWBC. If this is a kitchen counter outlet was it originally for the lighting? Or was the receptacle combined later with the light circuit? I interpret 2 BC's in the same box. Is this correct or am I in need of more info and most likely not on the same page yet. Tx, rbj

The brand is SQD QO. Yes, I agree that it is strange that there is only one outlet on this circuit. I don't know the original intent of the circuit and the house has had additions put on it. No barrier in the box in question and it is stuffed. That is why I did the breaker thing.

I really suspect that I will find something else on the circuit that proves to be the culprit. I have had pretty good luck with SQD stuff and I think the GFCI I installed is just doing it's job.