Hi, I just purchased a 2022 SE MINI Cooper, and the car comes with a charging cable with a built-in surge protector. The closest socket from my parking space is 50 feet away, and is a "Nema 5-20" (20 amps, 120 V, 1-phase). When I plug the charging cable directly into this socket, the surge protector "Power" led turns on, indicating all is well. But, when I plug in a 50-ft extension cord (12-gauge wire) into the socket then the charging cable into this extension cord, then the surge protector reads "Fault". This fault happens before I've even plugged the charging cable into the car.
So, is my extension cord simply not beefy enough, do I need a 10-gauge extension cord, with the special Nema 5-20 plug, rated for 20 amps?
Or, should I not use an extension cord at all?
Thank you for your insights and help.