Kohler 12RES Generator tripping GFCI outlets (update 9-21-22)

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Pacifico
Forum Member
Posts: 10
Joined: Fri Jan 21, 2022 10:47 pm
My RE system: Outback Radian GS 8048A inverter + load center
Morning Star TriStar MPPT -600Volt charge controller x2
MATE3s display/controller
Solar One HUP lead acid battery - 840 amp hour
4200kw array - twelve, 350 watt SolarWorld monocrystalline panels
MT Solar galvanized, single pole mount for the solar array
Kohler 12RES propane generator
Honda EU6500i gas generator
Note: panels mounted about 600' away hence the high voltage
charge controllers (higher voltage = smaller wire for the long run)

Kohler 12RES Generator tripping GFCI outlets (update 9-21-22)

Post by Pacifico »

(See update in eighth post dated 9-21-22 below)

Friends,

I recently added a Kohler 12RES propane generator to my off-grid system but am experiencing strange behavior when the generator runs and charges the batteries. Some, but not all of my GFCI protected house electrical outlets eventually trip, one by one, after about 10-20 minutes. It's always the same outlets that eventually trip and others never trip at all.

Some background:

My house was built 4 years ago according to modern codes by competent tradesman. It was built as an off-grid home. An experienced electrician and his apprentice did the house wiring and a solar contractor experienced in off-grid systems assembled and connected the off-grid power system.

When our off-grid system was installed, we used a Honda EU6500i as our backup generator since we already owned it and wanted to spread out construction costs over time wherever possible. For that reason, we only got around to having the Kohler 12RES installed a couple months ago. When we were charging batteries then and now with the Honda, we never experience this problem. Only when we use the newly installed Kohler generator does this happen so that's why I'm zeroing in as the Kohler being the source of this trouble.

The Kohler is set up to charge at maximum input for my battery bank but even if we dial back the amount of power, the specific GFCI protected circuits in the house still begin to trip one by one. Sometimes, one or more of the GFCI's will accept a reset while the generator is running but mostly, they stay tripped and won't reset until I turn the generator off. My solar contractor (who did the Kohler install) is at a loss to what's causing this behavior even after consulting with tech support.

I tried replacing one of the GFCI outlets with a new one just in case I had an unusually sensitive GFCI and it tripped just as fast as the original one. Again, only some GFCI outlets in the house trip. Others never trip at all.

Perhaps, one of you have seen this problem before and may have a direction to point me to in solving this mystery. If I can clarify anything, please ask.

Thanks in advance.

J
Last edited by Pacifico on Thu Sep 22, 2022 10:30 am, edited 2 times in total.
jbakker
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Posts: 276
Joined: Fri Feb 23, 2018 5:47 am
My RE system: 2 VFX3648 Inverters 2 FM60 150VDC Charge Controllers Mate3 5 KW of panels 15kw JC Onan NG Generator made in 1975.
1 Midnite Classic 150, FNDC. I have the Volt battery but it's not being used.
Now using 48 volt 800 AH Narada Lithium cells and QUCC 300 AMP 48 VDC relay BMS
Location: Goderich Ontario Canada

Re: Kohler 12RES Generator tripping (some) GFCI outlets

Post by jbakker »

Check to see if the Generator Neutral is bonded to the Generator frame.
I am assuming that the Generator is Grounded.
Only supposed to be one spot in the system where the Ground and Neutral are connected and that is the main panel in your house.
This may be the issue. There will be smarter people I am sure to help out soon as well.
raysun
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Posts: 8601
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Parallel Stacked, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Kohler 12RES Generator tripping (some) GFCI outlets

Post by raysun »

My first reaction would be to believe the generator is creating a ground fault.

Is neutral tied to ground at the generator?

If the ground between the generator and the inverter is removed temporarily, does the same tripping occur?
jbakker
Forum Guru
Posts: 276
Joined: Fri Feb 23, 2018 5:47 am
My RE system: 2 VFX3648 Inverters 2 FM60 150VDC Charge Controllers Mate3 5 KW of panels 15kw JC Onan NG Generator made in 1975.
1 Midnite Classic 150, FNDC. I have the Volt battery but it's not being used.
Now using 48 volt 800 AH Narada Lithium cells and QUCC 300 AMP 48 VDC relay BMS
Location: Goderich Ontario Canada

Re: Kohler 12RES Generator tripping (some) GFCI outlets

Post by jbakker »

RAYSUN we must have been typing a reply at the same time.

I suspect the generator neutral is bonded to the generator and the generator grounded to the main panel.

Let's hope he finds a solution
fcwlp
Forum Emperor
Posts: 1023
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Kohler 12RES Generator tripping (some) GFCI outlets

Post by fcwlp »

On the 12-RES the N-G comes bonded from the factory and is located in the junction box on the generator.
raysun
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Posts: 8601
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Parallel Stacked, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Kohler 12RES Generator tripping (some) GFCI outlets

Post by raysun »

fcwlp wrote: Thu Apr 14, 2022 4:26 pm On the 12-RES the N-G comes bonded from the factory and is located in the junction box on the generator.
So the solution is to remove the N-G bond (jumper) in the junction box. Hot L1, L2; N; and G; all connected to the GSLC (or whatever AC wiring panel is used) as per the normal scheme.
Pacifico
Forum Member
Posts: 10
Joined: Fri Jan 21, 2022 10:47 pm
My RE system: Outback Radian GS 8048A inverter + load center
Morning Star TriStar MPPT -600Volt charge controller x2
MATE3s display/controller
Solar One HUP lead acid battery - 840 amp hour
4200kw array - twelve, 350 watt SolarWorld monocrystalline panels
MT Solar galvanized, single pole mount for the solar array
Kohler 12RES propane generator
Honda EU6500i gas generator
Note: panels mounted about 600' away hence the high voltage
charge controllers (higher voltage = smaller wire for the long run)

Re: Kohler 12RES Generator tripping (some) GFCI outlets

Post by Pacifico »

Thanks everyone for your responses. I'll run your comments by my solar guy and see if some of these ideas aren't ones we've already considered or could try next. He'll be back soon to continue searching out solutions to this conundrum and I'll report back once this happens.
Pacifico
Forum Member
Posts: 10
Joined: Fri Jan 21, 2022 10:47 pm
My RE system: Outback Radian GS 8048A inverter + load center
Morning Star TriStar MPPT -600Volt charge controller x2
MATE3s display/controller
Solar One HUP lead acid battery - 840 amp hour
4200kw array - twelve, 350 watt SolarWorld monocrystalline panels
MT Solar galvanized, single pole mount for the solar array
Kohler 12RES propane generator
Honda EU6500i gas generator
Note: panels mounted about 600' away hence the high voltage
charge controllers (higher voltage = smaller wire for the long run)

Re: Kohler 12RES Generator tripping (some) GFCI outlets

Post by Pacifico »

September 21st update:

I am cautiously optimistic that the mystery of the tripping GFCI outlets when on generator power has been solved. It seems that the Leveton brand of GFCI's were overly sensitive and would all eventually trip within about 10 minutes of the Kohler generator coming on. all of the Leveton brand GFCI's were removed and replaced with a different brand made by Legrand. After running the generator for 40 minutes today, none of the Legrand GFCI's tripped!

Since my first post on this issue back in April, Kohler had been kind enough to send out an experienced Kohler generator repairman as well as a licensed electrician to look over my entire off-grid system since no one could make sense of why this was happening. Together with the solar contractor that installed my system and many calls to tech-support, they all spent quite a bit of time trouble shooting and testing. It was the electrician who suggested switching to a different brand GFCI after exhausting all other possible issues. He had a different brand GFCI outlet (made by Legrand) in his truck, popped it in and it seemed to work without eventually tripping like all the ones made by Leviton would do when the generator was running.

At that point, it was decided that we should try replacing all the Levtion GFCI's with Legrand GFCI's and see what happens. After another week, my order of a dozen Legrand GFCI outlets arrived and I replaced all the original Levitons with Legrand and anxiously awaited results after switching on the generator. After 40 minutes of the generator running, I didn't get any tripped GFCI's. I'll run the generator again in the morning and check all the GFCI's but I'm at this point, cautiously optimistic that this strange and frustrating conundrum has been solved.

I still don't know why none of this ever happened in the four years I was running a Honda EU6500i generator. It was only when I upgraded to the Kohler 12RES that the issue of the tripping GRCI's started. Some of the other electrical outlets in my house are served by Leviton brand combination GFCI/AFCI outlets and none of those ever tripped, only the GFCI's.
Last edited by Pacifico on Thu Sep 22, 2022 8:01 pm, edited 1 time in total.
fcwlp
Forum Emperor
Posts: 1023
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Kohler 12RES Generator tripping GFCI outlets (update 9-21-22)

Post by fcwlp »

Pacifico wrote: Wed Sep 21, 2022 9:00 pm He had a different brand GFCI outlet (made by Lebrand) in his truck,
Thanks for the update. For those of you looking for Lebrand GFCIs it is Legrand. :smile:
Pacifico
Forum Member
Posts: 10
Joined: Fri Jan 21, 2022 10:47 pm
My RE system: Outback Radian GS 8048A inverter + load center
Morning Star TriStar MPPT -600Volt charge controller x2
MATE3s display/controller
Solar One HUP lead acid battery - 840 amp hour
4200kw array - twelve, 350 watt SolarWorld monocrystalline panels
MT Solar galvanized, single pole mount for the solar array
Kohler 12RES propane generator
Honda EU6500i gas generator
Note: panels mounted about 600' away hence the high voltage
charge controllers (higher voltage = smaller wire for the long run)

Re: Kohler 12RES Generator tripping GFCI outlets (update 9-21-22)

Post by Pacifico »

fcwlp wrote: Thu Sep 22, 2022 5:51 pm
Thanks for the update. For those of you looking for Lebrand GFCIs it is Legrand. :smile:
Thanks, I corrected my post. Don't know how I missed the spelling, the box they came in is sitting right in front of me! #-o
raysun
Forum Emperor
Posts: 8601
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Parallel Stacked, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Kohler 12RES Generator tripping GFCI outlets (update 9-21-22)

Post by raysun »

still don't know why none of this ever happened in the four years I was running a Honda EU6500i generator. It was only when I upgraded to the Kohler 12RES that the issue of the tripping GRCI's started.
Im not sure it is causal, but the EU6500i is an inverter generator with very clean AC, while the Kohler is an alternator generator with (a bit less) clean AC.
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