How to Install a New Circuit in a House

Adding a new room, new appliance, or renovating an older home usually requires the addition of a new circuit to the breaker box to take on the new power load. Installing a new circuit is not difficult if you are aware of basic wiring techniques, but it should be done with extreme caution, like all other wiring projects. The breaker box will likely have an open spot or two for the addition of future breakers. Take advantage of these empty slots when installing a new circuit. Before adding the new circuit, install the outlets and pull AC cable through the house to the service panel, or do it after installing the new circuit but before restoring power.

Flathead screwdriver
Voltmeter
Hammer
AC cable from house, 24 inches
Needle-nose pliers
Cable clamp
Cable ripper
Wire cutter
Wire stripper
15 amp or 20 amp circuit breaker

Instructions

- 1
  Shut the main circuit breaker off at the service panel. Pry off the cover panel covering the circuit panel's wiring using the flathead screwdriver.
- 2
  Hold a voltmeter prong to the circuit breaker terminal screw and the other prong to the ground screw to verify that the power is no longer flowing to the breakers.
- 3
  Place the tip of a screwdriver against one of the circle outlines on the side of the service panel and tap the opposite end of the screwdriver with a hammer to knock out the circle for the wire to be inserted.
- 4
  Attach a cable clamp to the newly opened hole.
- 5
  Feed the AC cable from the house through the cable clamp in the side of the panel and tighen the clamp to secure the cable.
- 6
  Rip off the AC cable covering with a cable ripper from 24 inches at the end of the cable to expose the three wires inside.
- 7
  Separate the white, black and bare copper wires from the AC cable.
- 8
  Slide the end of the copper wire underneath one of the empty screws on the ground bar of the service panel. The ground bar will have bare copper wires going to it from the other circuits. Tighten the flat slot screw to hold the copper ground wire in place.
- 9
  Run the white wire to the neutral bar, which has white wires attached to it. Trim off the extra wire, strip off 1/2 inch of the coating from the end and slip the exposed wire under one of the empty screws in the neutral bar. Tighten the screw to lock the neutral white wire in place.
- 10
  Cut excess wire from the end of the black wire so it reaches the open slot for the circuit breaker. Strip off 1/2 inch from the tip of the wire and slide it under the screw in the new circuit breaker. Seal the black wire by tightening the screw on the circuit breaker.
- 11
  Press the circuit breaker into place until it clicks.
- 12
  Break off the spare circuit breaker cover from the service panel circuit breaker cover to correspond to the location of the new circuit.
- 13
  Place the service panel cover back over the circuit breakers, and turn the power back on.

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