The grounding wire for each circuit is connected to the distribution center and then is run with the hot and neutral wires in the branch circuits. Wire Connections Connections between wires are made inside plastic or metal boxes mounted in the walls or ceiling. Switches, receptacles, and wall or ceiling-mounted light fixtures all have their own boxes. Individual wires are wrapped in color-coded insulation for easy identification. Though hot wires are usually black or red, they may be any color other than white, gray or green.
Neutral wires are white or gray.
Grounding wires are bare or green. Occasionally, a white wire will be used as a hot wire. For easy identification, it should be taped or painted black where it's close to terminals and splices. The service entrance panel and distribution center in your home are equipped with either fuses or circuit breakers. These are the weak points of each circuit - the safety devices that keep the branch circuits and anything connected to them from overheating and catching fire.