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CODE-3 Ground Fault on Inverter after EV charging installed?

Posted: Fri Nov 28, 2025 10:29 am
by leSoleiletlaMer
Hello, am super happy to find this community of experts! Hope I can request some help.

We have 10 PV panels connected to an EP11 battery via an H1-G2 inverter installed in April and have been really happy with the system. We had a Ohme Home Pro EV charging point installed on Monday and ever since the app and inverter from panel have been reporting a CODE-3 Ground Fault that hasn't cleared down by a power off reset of the inverter/battery.

None of the RCD trips appear to be flipped and all the home electrics including the charging point appear to be working as expected, except the PV no longer charges the battery, so I've set a forced time charge to add some overnight energy (we're on Octopus Intelligent Go)

I am hoping the electrician is able to get back to check the connections sometime today, would be useful to know if there are any "gotchas" to look for - added some pictures of what the install looks like if that helps.
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Re: CODE-3 Ground Fault on Inverter after EV charging installed?

Posted: Fri Nov 28, 2025 11:43 am
by Dave Foster
A code 3 ground fault suggests that there may be a problem on the panel DC wiring - has there been any recent damage to your panels, possible water ingress ?

As a test you should be able to isolate the PV on the switch under the inverter and the fault should no longer be present - then it’ll be good old fault finding and checking for the electrician, possibly loose MC4 connectors or similar.

Re: CODE-3 Ground Fault on Inverter after EV charging installed?

Posted: Fri Nov 28, 2025 1:22 pm
by leSoleiletlaMer
Hi Dave , thanks for the reply, no changes other than installing the EV charger on Monday, after which the errors begain to show. Seems more than coincidental as they are both wired to the PV consumer unit :?

Will do as suggested and get the electrician back with a tester to see if can find any loose connections.
Cheers
David

Re: CODE-3 Ground Fault on Inverter after EV charging installed?

Posted: Sat Jan 31, 2026 3:30 pm
by sg125755
I'm having the exact same issue after an ev installation. What was the solution please?

Re: CODE-3 Ground Fault on Inverter after EV charging installed?

Posted: Sun Feb 01, 2026 1:36 pm
by leSoleiletlaMer
Hi, apologies for not updating this sooner.

TL/DR answer for us - turn the inverter and battery off, leave for 10-15 minutes then switch on again.

Took a couple of days but after conversations between the electrician and the EV company (Fresh Solar) it confirmed no ground fault was present anywhere on the EV charging installation (new breaker and cabling added next to the existing PV feed in the fusebox) or existing wiring. Chris, our very helpful PV installer at Fresh was out on another job but still made time to have a video call to check settings etc then suggested the power on reset procedure.

It seems that having not switched the battery and inverter off prior to the charger installation, the power off at the consumer unit may have tricked the system into seeing the failure as a ground fault, though why this didn't clear itself when power was turned on or why we couldn't reset via the app wasn't obvious.

Hope this helps!