My original 120V EVSE charge cord (orange lead) died after one week and would not provide any charge, even at 8 Amps. The new one worked fine for a week, but started tripping last week when on 12Amps. We had a heat wave, presumably putting more load on the grid-- perhaps that made a difference. I got a volt meter and figured out the the GFI plug was starting at 119V and dropping to 105V and would trip after 30 mins of charging.
I rigs up thick extension cord to a closer outlet and the voltage dropped from 120/121 down to 117/116V, and it fully charged twice.
Then today, I tried to charge off 120V at work-- which previously worked a couple of times with the old charging cable. You guessed it-- it tripped after about 30 mins.
I didn't bring my volt meter to work (I will), but was curious if others have noticed increased sensitivity on crappy outlets with the revised charging cord.