Charging trips GFCI breaker

I,m not an electrician but it seems to me it is not a huge surge, after all the load requested by car limits the current to 16 amp on 240 v.
I have a 100 000 Btu pool heatpump protected by a 40 amps GFCI Breaker and the surge is far more superior than your case ,It is a Scroll compressor and it never trips...I don't think it's the car. For what I know GFCI mesures leakeage between Ground and Neutral
Maybe @jerrymildred could chime in , if he is not on vacation

 

FIRST you need to look closely at the breaker to see if it is tripping because of excessive current OR because of a perceived ground fault.

I say "perceived" because a less than ideal connection anywhere in the circuit can cause the ground fault circuit to trip the breaker.
Even a loose ground wire. And unless it is a 4 wire 240 circuit, there isn't even a passive "ground" wire present.

Seems to me like it is a bit unusual to have a 240 circuit equipped with a GFCI.
Is that required by code where you are ?

 

a GFCI doesn't even need a ground wire. That's why code allows them to replace non-grounding receptacles on circuits that don't have a ground.

The principle of the GFCI is really simple: the current-carrying conductors that pass through it (usually a black and a white, but all three if it's a two-pole breaker) must be carrying current that sums to zero. Everything going on one wire must be returning on the other (or on the other two).

Any time the sum of the current on those conductors isn't zero, clearly some current is going someplace else, and the GFCI trips. Not a lot of chance to make the wrong call there.

I do agree it's important to determine whether the breaker is tripping because of its overcurrent-protection function or its GFCI function.

(For what it's worth, not long ago, I saw a drawing on the internet where somebody gave advice on connecting an exhaust fan to a GFCI, and showed splicing the fan's white wire directly to the white ones on the line side of the GFCI. The attentive reader may predict what that will do when the fan is turned on. )

Now, an AFCI breaker—for arc fault protection—does have a more complicated job. It has to recognize patterns of current draw that are typical of a flaky connection, but avoid tripping for things that can look a lot like that, say power tools or computer power supplies. I was recently reading about some AFCIs from Leviton that have upgradable firmware.

Hard for me to imagine a GFCI ever needing upgradable firmware.

But I wouldn't guess there's an AFCI involved in this thread. Unless the "GFCI breaker" that was put in was one of the newer dual-function ones.

 

Seemed like it used to be harder to find 2-pole GFCI breakers (I was looking around for one a few years ago to add to an old ConVerdant inverter. Now I notice them just hanging on pegs at Menards like regular stuff.

Salty though.

 

BUT.....if there is a ground wire present, it needs to have a good connection.
I know this from hard experience.

But then.......with a 3 wire, 240 circuit, is there even a true GFCI breaker available ?
I seriously doubt it.

And if that does exist, in what circumstances is it used ??

 

Well all I know is that a 2 pole 240vac GFCI breaker is monitoring imbalance between the 2 poles.If this happens some current is flowing to ground on the load circuit and the breaker trips.
Electric code in my province , rules that 240 VAc electric outdoor apparatus operating closer than 10 feet from a pool or a hottub or spa must have a 240 Vac GFCI breaker installed

 

Yes; these days they hang on the pegs at Menards right there with other circuit breakers 'n stuff. Easy to find. Bit pricey though. You can see these are 3 wire, by the white pigtail that has to go to the neutral bus. The circuit neutral, of course, has to attach to the breaker.

2-pole GFCI - Google Search

In the familiar single-pole GFCI, the black and white wires simply pass through a coil inside the unit. As long as what's going on one exactly equals what's coming back on the other, the total current through the coil is zero and nothing happens. Let the current going and coming be slightly unequal for any reason (and there's only one possible reason: some of it is following some other path), and now there is nonzero current flowing through the coil, the coil shows an induced voltage, and the GFCI trips.

To do it with a two-pole, three-wire circuit is no harder: just run all three, the white and both legs, through the coil. Normal operation will still have zero total current through the coil; it doesn't matter if what's connected is a 240-volt load and the current's coming back on the other leg, or a 120-volt load and the current's coming back on the white, or a combination with some of each. The total adding up all three currents will be zero, unless there is a fault current going someplace else.