EV charging on GFCI

Is the charger connected to a grounded mains socket ? Any current leaking from the L to PE can cause CFCI problems. You do not need a direct physical leakage to surrounding ground.

Mains EMC filter capacitors will let some current flowing from L to PE. If the capacitors are too large, this can trigger the GFCI.

In countries with unpolarized mains sockets try turning the plug around. The leakage might be slightly smaller from the other pole to PE and not trigger the GFCI.

Yes, would it be better not to connect the ground wire?

I have tried both ways. I might be able to wire a non GFCI socket directly to the main breaker box for now, but that's not always possible.

OK, i'll open it up to take a look later. I need to replace my axle and hub bearing first.

That is pretty dangerous. An internal ground fault could put full mains voltage to the car chassis for a long time. Only when barefoot touching the car would trip the GFCI (assuming it works properly).I dog might not like the small electric shock when sniffing or pissing on your car :-).

If you sometimes use this modified mains cord into a socket without GFCI (or faulty GFCI) and there is a real ground fault in the car, the car can be at the full mains potential even when touching the car chassis, possibly killing people.

A better solution is using a non-GFCI socket and use full (L+N+PE) cord. If there is a real ground short in the car, it will blow the mains fuse in a few seconds.

One solution is to use an insulation transformer 120/120 V (or 230/230 V depending on country).

Then by all means, cut the ground wire. I'm sure that will give the best result for everyone.

Q: WHAT’S THE PROBLEM with outlets on GFCI breakers – aside from cost? A: About 60% of the time, we find that EV chargers WILL NOT WORK on a GFCI breaker (true of both wall mount and “mobile connectors”). In those cases, when an EV charger is plugged in, the breaker trips (and won’t reset with the unit plugged in). This is because all EVSE already have GFCI technology built-in, and the two devices (GFCI breaker and GFCI charger) don’t play well together. This is an extreme version of the problem known as “nuisance tripping.”

Yes, this will come up again in another house. I am going to try to add a switch to by-pass the internal GFCI.

afaik RCDs are mandatory in EU, at least it is here. Though they are not like the US, they are at the fuse panel and ~30mA. So I'm sure the manufacturers have thought about it

VFDs and other big switchers are notorious for tripping RCDs, they don't like DC

Not needed with external GFCI. Needed for raw outlet. So, switching is an option.

his "charger" is probably a pile of random electronic scrap held together with zipties and chewing gum

No, it's a commercial sealed unit. You think i would bother with GFCI if I put scraps together?

isn't it the GFCI in the house that trips?

"the two devices (GFCI breaker and GFCI charger) don’t play well together"

That is some sort of official statement???

Can anyone explain why this would be? My understanding is the GFCI is just a toroid with both power leads wound through it so that is is sensitive to the difference in current only. This is sensed by an amplifier and used to control a relay. I can't see how cascading these would cause any problem.

Yes, because the GFCI in the charger is leaking.

I believe the GFCI in the device is part of the spec. I looked into building my own a few years back. It doesn't save much money, so I dropped the idea. But, the GFCI is in every EVSE you can buy.

It's leaking? Do you clean it up with a mop?

What is the EVSE leaking to? What makes you think it is "leaking"?

With an electronic mop.

It might be some biasing circuit to detect GFCI, but big enough to trigger an external GFCI.

One option is to ground the car itself, instead of the charger, and see what happen.

Very interesting. I'm going to see if that's the case in my garage. Thanks Don!