I have a NEMA 14-50 socket in my garage on a 50A breaker (6ga wire) setup. I originally had the 14-50 plug in wall charger, but it got replaced due to heating issues, and they don't make those any more so I got a gen2.
Rather than re-wire the whole thing, I used this:
General Electric WX09X10037 4-Feet 50-Amp 4 Wire Range Cord
https://www.amazon.ca/gp/product/B00LQDFOMY/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
and turned my wall charger into a plug-in charger limited to 40A continuous to satisfy code for a 50A breaker, using the rotary switch setting on the charger.
I had to snip off the lugs, the cable is stranded and it was a bit of a struggle to get everything connected within the confined case. The charger just uses black and red (and green, ground) so the white is capped. But - it works, it's a plug-in appliance now, etc. etc. while charging, the cable does not even feel warm to the touch.
I don't feel I'm losing anything since the max a model 3 (LR AWD) will do is 48A anyway.
Plus in the event of a charger problem, I have the 14-50 wall socket I can also use with the portable charger.
It sure beats hiring an electrician, getting permits, and losing the 14-50 wall socket.
EDIT: I see in my earlier ost I said a 40A breaker. When we got the plug-in charger, we decided to up the circuit to 50A and re-run with 6Ga not 8Ga (about 30 feet). Still had the 14-50socket, so with the Gen2 wall charger, I wanted to keep that socket. When trying to diagnose the heat problems with the plug0in, we switched to a Hubell 9450 industrial socket. Those suckers are $170 so why throw it away?
As I posted, I charge automatically starting at 1AM, so odds are dishwasher, stove, dryer will be done by then. Only competition on the service would be A/C which is 30A so highly unlikely I pop the main breaker. 40A is 57km/hr charge, so 1AM to 7AM will add almost a complete 80% charge to the battery.