# GFCI circuits trip on generator



## Slow_Floccer (Sep 10, 2020)

Hi all. I've only recently joined this forum and hoping to find some answers. Our newly-rebuilt off-grid cabin is wired for solar, but also wired at the main breaker panel to accept generator input for the whole structure. Our solar installation is not complete yet, so we're running (when we need to) the generator to power the fridge, some lights, water pressure tank, tankless water heater, that sort of thing. The problem is, we have 4 GFCI circuits in the cabin and when running the generator these circuits continually pop. After popping, sometimes they cannot be reset for a while, like 10-30 minutes, then randomly I can re-set them. Sometimes they'll stay "good" for an hour or more, and sometimes they pop again right away. It's really a mystery. The electrician has alternately blamed a bad batch of GFC outlets which he says he'll swap out. But now he's blaming the generator. We've used three different generators and they all cause the same GFCI faults. The most recent generator is brand new Champion model but still the problem persists. I think there is something wrong with the wiring (not the generator) because I read that many many people use a generator in this situation and no-one mentions GFCI faults.

Another oddity is that the brand new dishwasher will not run properly, it just stays at the start of cycle and never counts down. Also the GE range clock runs way slower than actual time. And the lights (all LED) flicker and surge to weird brightness when the dimmer is moved low-high-low.

I'm really not looking forward to a long drawn out troubleshooting with the electrician. I'm not sure they have the experience needed to troubleshoot this. Plus being off-grid and far from the city, the trips are very expensive. Can anyone here help with some troubleshooting suggestions? 

Thanks in advance!
Eric


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## iowagold (Jan 22, 2020)

is the generator bonded to the case frame of the generator?
if it is a construction open framed generator it is bonded from the factory.

but with the flickering..
that is an issue some where..
like maybe a neutral not tight in a plug or jack on the gen , or gen cord, or the generator inlet wiring.

check all of the screws!!
yup long day checking everything for tight!!
then do the tug test to make sure they are mechanical tight.
i have seen screws bind up and not grip the wires...
as well if there is any wire nuts any where in the system that also can be an issue.

i would start with a kilawatt meter
click here for the test tools page
that will show voltage as well as HZ.
and it also will show the load up to 15 amps for plug in items.

so what is the exact model of the champ generator?
and how are you connected from the generator to the cabin?
a custom cord or a factory made cord?

how is the breaker panel earth grounded?
and is it earth to neutral bonded at the breaker panel?


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## tabora (Sep 6, 2018)

Yup, must be an intermittent connection somewhere. I had a similar issue at my cottage where the GFCI kept popping and it turned out there was an internal break in one of the wiring runs feeding an outlet string from a sub-panel. Had to replace about 20 feet of 12-2G Romex.


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## Slow_Floccer (Sep 10, 2020)

iowagold said:


> is the generator bonded to the case frame of the generator?
> if it is a construction open framed generator it is bonded from the factory.
> 
> but with the flickering..
> ...



The brand new generator has neutral bonded to frame. The GFCIs popped and lights flickered with that. Champion website shows how to disconnect neutral from frame to make it floating and I did that..... same result, popping GFCIs. Flickering lights have been there since the beginning. That seems to be an indicator of bad wiring? My electrician seems to want to point fingers rather than go tug wires. I want to go tug wires but not sure where to start or how to measure "good" vs "bad". 

How can I use the KAW in this situation to find the problem?

The champion generator is the "Champion Power Equipment 100592 6250-Watt Dual Fuel Portable Generator with CO Shield technology "
The cord is a custom cord. 30amp at the generator side, 50amp at the house side.

As to "how is the breaker panel earth grounded".... well there is a rod pounded into the ground about 6 feet away and it is connected (I think, but have never checked....)
I don't know whether it is earth to neutral bonded at the panel. I can ask my electrician these questions or go look at it to determine. 

Thank you for your help/reply.
Eric


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## Slow_Floccer (Sep 10, 2020)

tabora said:


> Yup, must be an intermittent connection somewhere. I had a similar issue at my cottage where the GFCI kept popping and it turned out there was an internal break in one of the wiring runs feeding an outlet string from a sub-panel. Had to replace about 20 feet of 12-2G Romex.


How did you troubleshoot this? I believe this may be the problem but my electrician wants to point fingers at other issues. It's new wiring in new construction..... How can I diagnose a break like this?

One thing the electrician says is "all 4 GFCI circuits pop so it must be the generator. If only one GFCI circuit popped then it might be the wiring". Is his reasoning sound?


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## tabora (Sep 6, 2018)

Slow_Floccer said:


> How did you troubleshoot this? I believe this may be the problem but my electrician wants to point fingers at other issues. It's new wiring in new construction..... How can I diagnose a break like this?


Well, in my case it was fairly simple... My 2800W 120V Onan feeds a 25A GFCI box on my bathroom/tool shed. This constitutes the "Main Panel" and therefore my entire installation is GFCI protected. The shed just has one outlet block and a switched overhead light, and then a 75' 10-2G feed line goes to the cottage sub-panel (floating neutral). I turned off the cottage feed and all was well, so I knew the problem was not in the shed.









I isolated the 4 circuits in the main cottage, and then added them back in one by one until the GFCI at the shed popped. Of course, it was the circuit with the most outlets on it (four) and a long feeder since it was the farthest string from the panel. I got lucky and next isolated the first outlet in the string and the GFCI still popped, so it was either that outlet or the feeder line. I bypassed the GFCI and took my thermal imaging camera and scanned the line and there was a hot spot (just one little red pixel) about half way between the panel and the outlet. Replaced the feeder line and voila, c'est réparé!


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## tabora (Sep 6, 2018)

Slow_Floccer said:


> One thing the electrician says is "all 4 GFCI circuits pop so it must be the generator. If only one GFCI circuit popped then it might be the wiring". Is his reasoning sound?


Since it happened with multiple generators, I'd say no. I wouldn't have believed my problem would be a piece of new, faulty 12-2G Romex, but it happens! GFCI circuitry works by sensing a difference in the amount of electricity flowing into the circuit to that flowing out, even in amounts of current as small as 4 or 5 milliamps. Since it's happening intermittently, it could be caused by something vibrating the faulty (loose?) item. In my case, the neutral shielding was just thin in one place and was letting some return current leak onto the ground wire. I never knew it was there until I added the GFCI when I upgraded the generator.


Slow_Floccer said:


> As to "how is the breaker panel earth grounded".... well there is a rod pounded into the ground about 6 feet away and it is connected (I think, but have never checked....)
> I don't know whether it is earth to neutral bonded at the panel. I can ask my electrician these questions or go look at it to determine.


One thing about GFCIs: It's REALLY important that only a SINGLE neutral/ground bond be present in the system, and that should be at the main panel/ground rod. The generator neutral should be floating and there should not be another ground rod at the generator in most cases.


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## tabora (Sep 6, 2018)

Another thought: I just read the specs on your generator, and it says that the THD is 12-20%, vs an inverter generator or other high-end conventional generators that can have a THD of less than 5%. You may need to have a constant load item in the circuit to smooth things out (LED flicker)?

And a further thought: The specs say "*GFCI Protected Household Outlets - *Covered outlets include one 120/240V 30A locking outlet and four 120V 20A GFCI protected household outlets." If the L14-30 is GFCI protected, it may be messing with its downstream cousins... Although looking at the wiring diagram, I don't see any GFCI test/reset function for the L14-30 so I think that it actually is not GFCI protected.


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## Slow_Floccer (Sep 10, 2020)

Thank you so much for taking the time and your replies. My head is spinning a bit as to what to look at first but today I'm going through all the circuits on the panel. I'm going to turn them all off, then turn them on one-by-one to see if there are any individual circuits that, when on at the same time as the GFCIs, cause those to trip. 

Actually what I've found is that, if I turn every circuit off at the breaker/panel and turn on only the GFCI circuits, one at a time, they are each popping all by themselves. (well the first three did this. The fourth one hasn't popped yet.)

Anyway I just wanted to say thanks and I'll keep at it.


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## iowagold (Jan 22, 2020)

is any of the solar stuff integrated yet??
that could be the issue if it is.

just remember one set of 2 to 4 ground stakes for the earth ground.
the gfci units will detect any difference in the ground to neutral.

lol is the 4th gfci defective ??
could be causing the others to trip!!

also look for spider webs in the electric boxes..
i have seen those trip gfci units.


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