Converting a 220-volt circuit over to a 110-volt circuit isn't something most homeowners will have reason to do, but in some cases it's necessary. One such example is when you replace an electric dryer with a gas model. The electric dryer uses 220 volts, while a gas model only needs 110 volts because the heat is produced by gas, not electricity. Knowing how to convert the wiring will save you from having to run a new circuit.
Changing the Wiring on the Outlet Side
Turn off the double-pole breaker that powers the 220-volt circuit. A double-pole breaker takes up two slots in your electrical panel, but it's controlled by a single breaker switch.
Test the 220-volt outlet with the voltage tester to make sure the power is off.
Unscrew and remove the outlet's cover plate and the two screws that secure it to the wall box. Carefully pull the outlet out of the wall box.
Loosen the terminals on the outlet and disconnect the wires. Check the ends of the wires for any corrosion or other visible problems. If needed, cut away the existing exposed wire and use the wire strippers to strip about 3/4 inch of new insulation away from the ends of the wires.
Connect the ground wire to the green ground screw in the new 110-volt outlet, the white wire to the silver terminal screw and the black wire to the bronze terminal screw.
Wrap the terminals with a layer of electrical tape and secure the outlet to the wall box using the top and bottom screws. Then, install the receptacle plate.
Changing the Wiring in the Panel
Remove the electrical panel cover. You may need someone to give you a hand, as panel covers can be heavy and difficult to manage while you're removing the screws. Use extreme caution while performing this portion of the job. The electrical panel is live.
Find the circuit breaker you turned off earlier. Look in the panel to see if you have any available spare 20-amp breakers (meaning one that does not already have a wire connected to it).
Turn off the 20-amp breaker you are going to be using and loosen the terminal screw where the wire gets inserted.
Loosen the two terminal screws on the original double-pole breaker (which should still be off) and carefully pull out the black-and-white wires. Bend the wires safely out of the way.
Locate the neutral bar inside the panel. It is the silver bar with a lot of screws in it; plus, you'll see all of the other white wires connected to it. Loosen one of the unused screws and insert the tip of the white wire under it. Tighten the screw to hold the white wire in place.
Insert the black wire under the terminal on the 20-amp breaker and tighten the screw down to hold it in place.
Replace the electrical panel cover and turn the 20-amp breaker on.
Test the outlet for voltage. The outlet should now be reading between 110 and 120 volts.