A circuit breaker provides a safety between the electricity entering your home and an electrical circuit. The breaker will trip when an electrical circuit draws more power than a breaker's rated amperage. During the installation of a new electrical circuit, you will have to install a circuit breaker in the breaker panel supplying power to your home. Properly connecting the electrical circuit to the breaker will safely supply power to the new circuit.
Turn off the main breaker of the breaker box. Touch one "hot" and one "ground" wire in one electrical circuit with the leads of a voltage tester. Check to ensure the main breaker is off if the light on the tester lights up.
Remove 1/2-inch of insulation from the white "neutral" wire and the black or red "hot" wire with a pair of wire strippers.
Loosen a ground bus bar screw---containing no wire---by turning it counterclockwise with a flathead screwdriver. Slide the end of the bare grounding wire under the loosened screw. Tighten the screw to secure the wire. Connect the bare end of the white neutral wire to the neutral bus bar using the same method.
Turn the screw located at the back of the breaker counterclockwise with a flathead screwdriver. Slide the bare end of the black or red "hot" wire between the two plates located below the breaker screw. Tighten to screw to secure the "hot" wire.
Align the breaker clips with the bars located on the back of the breaker box.
Turn on the main breaker. Touch one lead of the circuit tester to the "hot" wire connected to the breaker and the other lead to the "ground" wire.
Use electrically insulated tools to avoid a potential electrical shock.