Open your electrical panel, find the main circuit breaker, and flip the switch to the "off" position. The main breaker has the highest ampere rating among all the breakers, and is commonly installed on the top of the panel. Unscrew the electrical panel cover using a screwdriver.
Place a receptacle box on the spot where you wish to install the 220-volt outlet and trace its outline using a pencil. Cut out the drywall by running a utility knife several times along the outline. Insert the electrical cable into the hole, fish the wires up the wall, and pull it up from inside the ceiling, making sure to leave two feet of cable dangling from the wall. Insert the cable through a hole on the receptacle box and push the receptacle box into the hole. Turn the two screws in the front of the box clockwise to flip out plastic swing clamps that will hold the box against the drywall. Tighten the screws to secure the box.
Run the electrical cable across the ceiling and drop it through a vacant or available conduit pipe above the electrical panel. Pull the cable carefully from inside the electrical panel and cut using diagonal pliers it when it reaches the bottom of the panel.
Strip off about four inches from the tip of the cable's outer covering using diagonal pliers. Do not cut through the insulation of the inner wires.
Loosen the gold-colored terminal screws on each side of a 220-volt 30-ampere receptacle using a screwdriver. Loosen the green terminal screw at the bottom of the receptacle. Wrap the black wire clockwise around the gold terminal screw on one side of the receptacle, wrap the white wire clockwise around the gold terminal screw on the other side of the receptacle and tighten the screws. Wrap the bare or green wire around the green terminal screw and tighten the screw to secure the connection.
Wrap electrical tape around the white wire near the receptacle to indicate that the wire is live. Wrap electrical tape two times around the side of the receptacle to cover the terminal screws. Tuck the wires gently in a zigzag pattern into the outlet box. Mount the receptacle onto the outlet box using the screws supplied with the receptacle.
Get a 220-volt circuit breaker from your local hardware and turn the switch on top of the breaker to the "off" position. Hold the breaker above the vacant slot with its terminal screws facing away from the center of the panel and its switch facing toward you. Push the breaker into the slot to engage the copper clips beneath it onto the metal bus bar on the breaker panel.
Hold the white and black wires dangling from the conduit pipe above the breaker, and arrange the wires neatly so that they will reach the terminal screws behind the 220-volt circuit breaker. Route the gray or bare wire to a vacant terminal screw on the ground bar. Cut the wires once they reach the terminal screws and strip off 1/2 inch of insulation from the tip of each wire using a wire stripper.
Loosen the terminal screw on the ground bar, and loosen the two terminal screws at the end of the breaker. Insert the stripped end of the black wire into the hole at the base of the terminal screw on one side of the two-pole breaker, and insert the stripped end of the white wire into the the hole at the base of the terminal screw on the other side of the breaker. Insert the ground or bare wire into the hole at the base of the terminal screw on the ground bar. Turn the three terminal screws clockwise to tighten them, and pull on the wire slightly to make sure that they are not loose.
Turn the switch on top of the main circuit breaker to the "on" position. Turn the switch on top of both poles of the 220 volt circuit breaker to its "on" position. Plug a 220 volt appliance to the receptacle, and turn on the appliance.