I realize this question doesn't have anything to do with wood heat, but since I know there are alot of tradesmen on the forum, I though I might get a quick answer. My sister is renovating some property she bought. She had a Electrician/HVAC guy who is an idiot. I won't go into all the problems I've called him on so far, but calling him an idiot might be giving him too much credit. Today he was hooking up the first outside AC unit. It's a standard 220 ton and half unit. He was wiring it with 12-2 wire. I told him that wouldn't work. He said it would. So I clarified, It will work but it's not up to code. He is run one 110 leg through the black/hot wire; the second 110 leg through the white/common wire; and the bare wire goes to ground back at the circuit box. we got into an argument over the ground wire being the common. He said it doesn't have a common wire on it only a ground. I said your ground wire is acting as a common and you don't have a ground. Can you guys please clarify this? And if you have time maybe post a link where I can get the information to print out for him. Or tell me he's right and I'm wrong. Thanks.