When plugged into shorepower GFI, it trips the breaker

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pwoens asked Jul 9, '23

When plugged into shorepower GFI, it trips the breaker

Install is in a MB Sprinter

Victron Multiplus 12/120/3000

5 BattleBorn lifepo4 100 batteries in parallel

Lynx, Cerbo, Touch. MPPT, DC to DC, etc

All wires are proper gauge

Built the van over the winter and once all electrical was done I kept it plugged into shore power in my shop, which was 12/2 romex 20amp breaker with a GFCI receptacle. It never tripped breaker or GFCI after the build was done. It wasn't until about a month ago that the GFI started tripping. I plugged it into a different breaker with no GFI and it runs fine. Took it to our river property and plugged into the 30 amp GFCI breaker there and it tripped breaker every time the MP tried to switch over.

Ground and neutral bars are separate in my vans breaker panel. I went ahead and disconnected AC wires coming out of the MP that fed the breaker panel and still same issue. I lowered the limit in the MP to 15amp to see if that would help and same results. I also turned the disconnect to the batteries off and same issue.

I am sure its something simple I've overlooked but hoping for ideas.

Ground from Lynx is a 2/0 straight to medal wall of the van. Ground from the MP is to same wall of the van but is an 8 gauge

Thanks in advance for any ideas or suggestions.

wiring Help

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Answer 1 · 2023-07-10T12:59:52Z

mvas answered · Jul 10, 2023 at 12:59 PM

Ground Relay configuration and actual operation?

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Answer 2 · 2023-07-10T15:06:38Z

pwoens answered · Jul 10, 2023 at 03:06 PM

@mvas apologies for my ignorance, what do you mean "Ground Relay Configuration"? I sincerely appreciate your input!!

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Answer 3 · 2023-07-11T02:33:37Z

mvas answered · Jul 11, 2023 at 02:33 AM

Disconnect AC power wires going into and out of Multiplus. Check for "leakage" between Neutral connection and Ground connection on both the AC Input and then the AC output terminals. Use Ohms setting on Multimeter. N-to-G should be an open circuit. Somehow you have some current returning via the ground wire, instead of 100% coming back through the neutral wire only. The internal "Grounding Relay" re-connects N-to-G internally. This re-creates the N-G Bond only when running off-grid. If it is stuck "closed" it will trip GFCI.

Somewhere you have "leakage" ( low ohms ) between Neutral & Ground.

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