Hello, I`m new here, so I hope this works, and goes to the right place. Any way, I have a contractor comeing to hook up a air condition unit, and I told him, I will bring the 220v line thru the wall, and he will take care of the rest. My house was built in the early 60`s, so I have to add a subpanel, to get the 220. The way I`m thinking is to take the two legs from the main fuses, and bring it into the subpanel. The sub will be as small as I can find it, maybe 4 circuits. I know that the 220, will take 2, 20 amp circuits, and I have no plans on adding any more. My first question is, is it a good idea to take the two legs from the main fuses, and what size wire should I use to add the subpanel, I`m thinking 10, maybe 8 if I can find it. The wire to the air condition unit will be 12-2. They require a 20 amp, circuit. Any help, will be appreciated.