The 1.2T miners that AMT sells come with 1500W power supplies. It's pretty much common sense. Like I said, a 20amp dedicated circuit will do fine.
Now, if you plug and air conditioner, a hair dryer and plasma TV and sump pumps on that same 20amp circuit, you will overload it since a 20a would take up to 2000W for sure. I Thought that was obvious, but I will state it here so you know.
1 1.2T miner draws about 10 amps. You should only put 1 miner per 20 am circuit.
if you are want to run multiple per circuit you should run 208 30 amp. You could run 3 miners. ** Check with you electrician.