I used to charge off of a GFCI. Technically it was an outlet daisy chained after the GFCI outlet (I know, I know, dedicated outlet and all that junk, but it was a 20A circuit and only the garage door was on the same circuit).
Are you saying you have multiple wires on the ground screw? Because that is not allowed.For those who think I don't have a ground line, my sprinkler system controller is "load" tied to the outlet and it also requires a ground to operate as it's an outdoor controller mounted inside the garage. It worked properly with the GFCI as it connects to the load and ground screws on the back of the outlet.
Back stab connections only accept 14 ga wire anyway.On the flip side I verified that I used the wrap method for the wires when I installed the outlet in the first place. I've never liked the push in concept for wiring as I can't see inside the outlet to verify good and solid mechanical connections. 10 gauge wire is hard to wrap around the screws but I wrapped so I could visually verify a good mechanical connection to the outlet. The two circuit lengths are 10 ft and 40 ft and I'm using the shorter one for my EVSE.
#1: Why are you using #10? 20A circuit only requires 12 ga.Three strand 10 gauge wire cable, Black - Hot, Red - Neutral, and bare ground. (I couldn't find Black/White/Green in 10 gauge at the time.) As I posted my sprinkler system controller requires a ground wire as well since it's designed to be installed outdoor with a direct tie to the circuit. It works. My EVSE works on the original non-GFCI outlet as well.
Not true. All 20A outlets are rated for #10 wire. They have to be in case you have to upsize the wire for extra length.The majority of 120V outlets are not designed to accept wire thicker than 12 gauge, and using 10 gauge wire creates a potential unsafe condition and would not pass inspection. A safe workaround is to use a 12 gauge pigtail with a wirenut.