A while ago I bought a California style plug to NEMA 14-50 adapter for possible use at horse shows that I frequently attend. I was at one this weekend and as I looked up from our barn stall area I found such a receptacle attached to a rafter. Here it is with the adapter plugged in: First time I've been able to use this adapter and of course this horse show was 10 minutes from my house so I didn't need the charge. I got a nice 40 amps at 240v from it when I tested it. Question for the electricians out there. This is a large facility and I know they have to have three phase power running through it (Del Mar Fairgrounds) but the car initially sensed 246 volts which went down to 240v under load. How was it not 208v?