There are three things you must take into consideration when wiring a 220-volt outlet. First, 220-volt circuits do not use neutrals. Second, hot wires going to the receptacles alternate with each other. The electrons go into the circuit through one wire, and then move out of the circuit through the second wire, creating electricity. Third, the outlet itself is different in shape (and sometimes in size) from a 120-volt outlet. Each application or appliance will require a special outlet to fit the plug that comes with it.
Turn off the power and follow all safety precautions concerning electricity.
Run No. 12/3 wire from the panel to the outlet location. Normally, only one outlet can be used for each circuit. Strip 12 inches of the sheath off of both ends of the 12/3 wire. Inside the wire's sheath, you will find three wires: a black wire (hot), a red wire (hot) and a green wire (ground). Sometimes there will be a white wire as well, which is not connected.
Strip 1/2 inch of the wires' insulation off to expose the inner copper wires. The 220-volt/20-amp circuit breaker is actually a double breaker in one and has two terminal screws attached to it. Insert the red wire under the first terminal screw and the black wire under the second terminal screw. Tighten both screws to secure the wires in the circuit breaker.
Insert the black wire on the outlet into the terminal screw. There should be a marking on the outlet that shows where each wire should be plugged in. The black wire may have a mark that reads: "Black," "Hot" or just "B." The red wire may read: "R," "Red" or "Hot." The green wire may have just a green terminal screw or a mark that says: "G" or "ground." The mark on the white wire, which may be used on some appliances, may read: "White," "W," "Neutral" or just "N." Match each wire to its terminal screw. Insert the wire under the screw, and then tighten the screw to complete the connection.
Some appliances will require a fourth connection for "neutral" (e.g., to power an oven light in a 220-volt oven or an indication light on a 220-volt dryer). In this case, use No. 12/4 wire.