Just bought a Tesla Model 3, most fun car I've ever driven. 120 volt charging was a joke, 3-5 miles per hour wasn't going to work. Had an electrician put in a 240 volt 30 amp circuit that gets me 24 miles per hour. Things are good. But, I'm a little concerned about the installation. I read up on it and I understand that electricity coming into the house is at 240. The main box provides 240 to the AC, water heater, range, and the box in the garage. The box in the garage splits that 240 into two 120 phases with half the circuits being on one phase and the other half on another. All the stuff I've seen says you put in a 30 amp breaker that fits into and pulls from 2 adjacent slots to achieve 240.
My guy tells me that my box doesn't work that way. So he put a 30 amp breaker in one slot and put another 30 amp breaker in the slot 2 below that one, not the adjacent one. Those joined together to power the 240 outlet. Well, it works so I'm guessing he's right, but does that make sense? When I sell the house am I going to be told it's not up to code?