Home circuit breakers come in two types: single pole (120 volts) and double pole (220 volts). Common appliance ratings range from 10 to 40 amperes, although higher amperages are sometimes required. Appropriate wiring and installation is necessary for both types to operate correctly and safely. Although double pole circuit breakers are commonly used for appliances, they do have other uses such as multi-wire circuits and powering sub-panels.
Turn off the main breaker. You will be working in close proximity to the exposed bus bars of the circuit panel and dangerous currents and voltages. Be safe--turn it off. Turn on your work light and you're all set to start.
Remove the panel front cover. Usually, these are held in place by large combination sheet metal screws sized for a #2 slotted or square head screwdriver.
Move a 120 volt breaker to another empty position. (Only perform this step if two breaker positions are not adjacent, usually one on top of the other.) Gently pry one up from the center with a slotted screwdriver until it pops loose, then remove it and position it in an empty slot on the other side of the panel. In some cases, you might have to rearrange more than one breaker if the panel is nearly full.
Install the new 220 volt circuit breaker. The breaker attaches in two places: one has conductors in it, the other does not. Place the non-conducting side in first, then push the breaker in at the center until it snaps into place. If the breaker is not in the off position, turn it off now.
Before proceeding with wiring, make sure the breaker is firmly seated in place and that the switches are in the off position before wiring the circuit. If you will be wiring the circuit later, tape the switches in the off position and follow step 5 in section 2.
Open a new "knock out" by tapping it lightly with a screwdriver and hammer. Then grasp it and twist it out with the pliers. Install the proper bushing or connector, then bring the wire into the panel, leaving plenty to work with. If using cable, trim all but one inch of cable insulation away from the cable that is inside the box, leaving only the insulators on the individual wires.
Begin with the ground wire if there is one. Route it neatly along the others to the grounding bar, trim it to length, strip if necessary and put it in place, tightening down the screw with a #1 square head screwdriver.
If the neutral bar is separate from the ground bar, connect the white neutral wire to the neutral bar. Route the wire neatly, trim to length and strip off 3/4 inch of insulation. Put it in place and tighten the screw with a #1 square head screwdriver.
Neatly route both colored "hot" wires to the new circuit breaker. Trim to length, strip 3/4 inch of insulation away and place each wire under separate terminal plates. Tighten the terminal screws securely with a #1 or #2 square head screwdriver.
Remove the blank knockouts from the circuit panel cover that correspond to the new locations used. Install the panel cover, add a label for the new circuit breaker and you are finished. At this point, you can turn the main power back on. Leave the new breaker off until you complete the circuit wiring.