Things You'll Need
110-volt circuit breaker, 20 amp
Wire cutters or strippers
A circuit breaker is what controls the power to an electric circuit. The circuit breakers in the main service panel of a house are typically rated for 110 volts or 220 volts. Most home devices, such as lighting and most outlets, are wired to 110-volt breakers. When you add a new circuit, you will need to installing a 110v breaker in the service panel to complete the circuit. Be sure to talk with an electrician if you have any question before beginning this project.
Turn the main power breaker to the service panel to the Off position. The main breaker is typically labeled and located at the top of the service panel.
Use your screwdriver to remove the screws securing the service panel's cover door. Remove the door and set it and the screws to the side for later reassembly.
Locate an open bay or slot in the service panel to insert the new circuit breaker. Line up the circuit breaker over the slot. Slide the breaker into the slot and push down to lock the U-shaped clamps on the bottom of the breaker onto the pins in the slot. You will hear the breaker snap into position.
Strip 1 inch of insulation from the ends of the wiring that is to be connected to the breaker you have installed. Attach the bare wire to the grounding strip at the bottom of the service panel. Attach the white wire to the neutral bus strip running down the center, and attach the black wire to the single screw on the breaker. Use the screwdriver to tighten all the screws to hold the wires in place.
Line up the cover door with the service panel and punch out one of the knockout slots to allow the breaker's switch to extend through when the door is reassembled. Use the screwdriver to punch out the tab.
Replace the cover door and secure it in place with the screws you removed earlier. Tighten them with the screwdriver.
Turn the main breaker and the new breaker to the On positions to test for power.
Never work on a service panel without turning off the main breaker to the panel. The high voltage within the panel can cause serious injury or death if you do not take precautions.