# Generator gfci breaker tripping on transfer



## joebanana (Dec 21, 2010)

Did you read the manual? Look in the troubleshooting section. Did the xfer. sw. come with the unit?


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## nrp3 (Jan 24, 2009)

On the surface, you have the right kind of transfer switch for a generator with a GFCI panel on it, one that switches the neutral. In theory it should work. I have installed one before, but on a bonded neutral/ground generator without the GFCI panel.

Looking online, there was an optional transfer switch made by Cutler Hammer that would switch the neutral available from Briggs, though I don't know if it's available anymore. May still be available from Cutler Hammer. I'd have to look. 

Kind of a unique model, a standby with a portable type panel in it, with connections for a couple of BBQ grill tanks.


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## paulengr (Oct 8, 2017)

You said trips....does it grunt during transfer? How much does your amp clamp read as a surge during transfer? It better NOT be GFCI...Just regular ground fault for equipment which is what it should be.

If you start and run after transfer dies it trip? Thinking it can't handle the load or there's something wrong with either the regulator or the breaker. Do you have access to a load bank? Was it installed by generator company?

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## gpop (May 14, 2018)

joebanana said:


> Did you read the manual? Look in the troubleshooting section. Did the xfer. sw. come with the unit?


 
The switch did not come with the generator. The switch is new and the generator is probably 8 years old.

I have read both manuals cover to cover and ive emailed the xfer panel manufacture to see if they will assist. There is no controls diagram with the switch so theres no way to check if the unit was wired correctly at the factory. Ive triple checked the house wiring and followed there start up and test procedure and the switch passes every test until you switch with both the generator and house wiring being live at the same time.


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## nrp3 (Jan 24, 2009)

It is GFCI (for personnel) and there are a few out there that come this way.


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## gpop (May 14, 2018)

After spending a little time trying to backwards engineer the switch I keep ending up thinking its the coil. I still can not work out how a coil that had 4 wire can have one cut off at the factory and work as a 3 wire coil. 

The coil has 2 white wires and one orange wire (second orange was cut off real short near the coil). Resistance measured between any of the 3 wires reads about 4.8m ohm which seems high for a 240v coil. Starting to draw a diagram to see if it makes more sense on paper. (every transfer switch I have worked on has always had 2 coils to do the transfer so this single coil seems weird.


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## gpop (May 14, 2018)

paulengr said:


> You said trips....does it grunt during transfer? How much does your amp clamp read as a surge during transfer? It better NOT be GFCI...Just regular ground fault for equipment which is what it should be.
> 
> If you start and run after transfer dies it trip? Thinking it can't handle the load or there's something wrong with either the regulator or the breaker. Do you have access to a load bank? Was it installed by generator company?
> 
> Sent from my SM-T350 using Tapatalk


I wish it was something as simple as surging during transfer but with all the load breakers turned of it does the same until the 50 amp in the main panel is switched off. To me that sounds like the generator and house is bleeding across at some point during the transfer. 

Both the generator and transfer were installed by me. Generator is on a pad and prewired and plugs in so no wiring on that side. Transfer is designed to be installed by a home owner and is prewired. 

It was my first time ever working with romex but ive been a industrial E&I for 12 years so I should be as qualified as a average home owner.


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## gpop (May 14, 2018)

nrp3 said:


> It is GFCI (for personnel) and there are a few out there that come this way.


It seems this generator was designed to be used on new home building sites. The generator should be set up and a ground rod installed then checked by the building inspector before being used to power the worksites tools.


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## nrp3 (Jan 24, 2009)

Have a Megger? Or access to one? I'm leaning towards a short somewhere too. This problem would show itself when people would buy portables with panel gfci protection and then try to use interlocks or some non neutral switched transfer switch.


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## paulengr (Oct 8, 2017)

gpop said:


> I wish it was something as simple as surging during transfer but with all the load breakers turned of it does the same until the 50 amp in the main panel is switched off. To me that sounds like the generator and house is bleeding across at some point during the transfer.
> 
> Both the generator and transfer were installed by me. Generator is on a pad and prewired and plugs in so no wiring on that side. Transfer is designed to be installed by a home owner and is prewired.
> 
> It was my first time ever working with romex but ive been a industrial E&I for 12 years so I should be as qualified as a average home owner.


That sounds exactly like it, which is why I asked about grunting. It sounds like both sides of the transfer switch closed in. In most of them this should be impossible at a residential level.

In order to do a closed transition (both sides connected simuktaneously) the generator has to be synchronized to utility power nd there is also always a sync relay to double check this. In utility generators they typically run theirs slightly off frequency such as 60.1 Hz and then when it gets within say 10 degrees of utility, close the breaker. Once synced the generator will not unsync...It generators negative or positive torque to stay aligned. If it's far out of sync, you get a massive current draw from the counter-EMF and either the generator burns up or the breaker trips or both.

I mostly do commercial/industrial and in those the transfer switches that are open transition only have mechanical and electrical interlocks that prevent a closed transition. If that coil wire is busted and there's no protection you could be closing into the utility with the generator. Something odd about what you said. Just like a single phase motor if we have two coils with 3 wires so sharing a common somewhere, we'd expect R1, R2, R1+R2 ohms across the coils, not R1=R2=R3.


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## gpop (May 14, 2018)

paulengr said:


> That sounds exactly like it, which is why I asked about grunting. It sounds like both sides of the transfer switch closed in. In most of them this should be impossible at a residential level.
> 
> In order to do a closed transition (both sides connected simuktaneously) the generator has to be synchronized to utility power nd there is also always a sync relay to double check this. In utility generators they typically run theirs slightly off frequency such as 60.1 Hz and then when it gets within say 10 degrees of utility, close the breaker. Once synced the generator will not unsync...It generators negative or positive torque to stay aligned. If it's far out of sync, you get a massive current draw from the counter-EMF and either the generator burns up or the breaker trips or both.
> 
> ...


Im not black lighting on to the grid this is a simple sub panel with 2 feeds that are separated by a transfer switch

I finally figured out that the coil is more than just a coil. Im not exactly sure what component it contains but the resistance rises rapidly. (it may also contain a diode)

The generator gfci tripping is annoying (when it trips it shuts the generator off) but after multiply tests I can find no safety risk to a lineman or to the generator so I can learn to live with it. While running on the generator I used a plug in gfci tester and the generator tripped as well as the gfci receptacle which may be a pain during a black out but its something I can live with until I buy a more suitable generator. 

My biggest concern was something wired wrong on the factory side that could lead to a un-safe problem.


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## gpop (May 14, 2018)

nrp3 said:


> Have a Megger? Or access to one? I'm leaning towards a short somewhere too. This problem would show itself when people would buy portables with panel gfci protection and then try to use interlocks or some non neutral switched transfer switch.


I figured testing any receptacle that's live when the generator is powering the house with a plug in gfci tester was just about equal to doing a meg test. Generator tripped during the test so everything on the panel is gfci protected.


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## MDShunk (Jan 7, 2007)

You have a N-G bond at the panel end and a N-G bond at the generator. Of course the GFCI trips.


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## gpop (May 14, 2018)

MDShunk said:


> You have a N-G bond at the panel end and a N-G bond at the generator. Of course the GFCI trips.


I'm not sure what you are trying to say.


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## Wiresmith (Feb 9, 2013)

gpop said:


> I'm not sure what you are trying to say.


if its a closed transition switch you likely have 2 main bonding connections during transition. you will have neutral current on a ground path, and your neutral current will be lower than your ungrounded conductor's imbalance current so your gfci trips


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## gpop (May 14, 2018)

Wiresmith said:


> if its a closed transition switch you likely have 2 main bonding connections during transition. you will have neutral current on a ground path, and your neutral current will be lower than your ungrounded conductor's imbalance current so your gfci trips


I had to google that. Makes sense on the coil side of the switch (micro switchs). I presume this is to prevent the switch from hanging half way during the transition with no power to the coil. 

Thanks


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## turnerjr (Jan 17, 2020)

GPOP, did you ever resolve your issue with the your generator gfci breaker tripping when you operate you generac 6582 transfer switch? I have the exact same issue with my setup. I have a generac 6852 transfer switch and a generac xc8000e generator. Likewise my generator main gfci breaker trips when transferring back to utility power.


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## Wirenuting (Sep 12, 2010)

turnerjr said:


> GPOP, did you ever resolve your issue with the your generator gfci breaker tripping when you operate you generac 6582 transfer switch? I have the exact same issue with my setup. I have a generac 6852 transfer switch and a generac xc8000e generator. Likewise my generator main gfci breaker trips when transferring back to utility power.


Turnerjr welcome to ET

Please take the time to fill out your profile. 
Them start a new thread to ask about yours.


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## gpop (May 14, 2018)

turnerjr said:


> GPOP, did you ever resolve your issue with the your generator gfci breaker tripping when you operate you generac 6582 transfer switch? I have the exact same issue with my setup. I have a generac 6852 transfer switch and a generac xc8000e generator. Likewise my generator main gfci breaker trips when transferring back to utility power.


Nope still does it due to the coil design.


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## CoolWill (Jan 5, 2019)

gpop said:


> Nope still does it due to the coil design.


What do you mean? How does the coil design trip the GFCI?


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## gpop (May 14, 2018)

CoolWill said:


> What do you mean? How does the coil design trip the GFCI?


If you read the old post there's more detail. The jest of the problem is the transfer switch was designed cheaply and only used one coil with 3 wires rather than 2 separate coils. 
Tbh the transfer switch was designed to be sold for use with a generac generator (non-gfci) and the briggs i own should have been used with there transfer switch. Funny thing is turnerjr has a generac generator with a gfci so tech support should be able/forced to help him (they refused to help me as my generator was not a generac)


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## KLG3 (Jan 5, 2022)

gpop said:


> Generac manual transfer panel 6852
> Briggs and straton propane 7kw generator 040248
> 
> The transfer switch is a 3 contact switch (switchs neutral).
> ...


This problem is caused by the millisecond delay in the contactor points. If the hot hits a split second before the neutral, you get a GFCI trip. The solution for us was to bond the transfer switch neutral to the transfer switch ground lug with a small 8 gauge jumper. Then the neutral is always sensed by the GFCIs for that split second and the GFCIs stop tripping on startup.


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