What electrical wire color codes mean
All electrical wires are made according to standard color codes which identify each wire's function in a circuit. Knowing which wire does what is imperative not only in the correct configuration of an electrical system, but it is also paramount for homeowner safety.
Black: Black is used for power in all circuits. Any circuit's black wire should be considered hot or live. Black wire is never used for a ground or neutral wire and should be used to as the power feed for a switch or an outlet. A black wire is often used in a circuit as a switch leg, the connection that runs from the switch to the electrical load.
Red: Red indicates the secondary live wires in a 220-volt circuit, used in some types of switch legs and in the inter-connection between smoke detectors that are hard-wired into the power system. A red wire can be connected to another red wire or to a black wire.
Blue and yellow: Yellow and blue are also used to carry power, but are not for wiring the outlets for common plug-in electrical devices. These colors are used for the live wire pulled through conduit. Yellow is used mainly as switch legs to fans, structural lights and switched outlets. Blue is used mainly as a traveler for a three-way or four-way switch.
White and gray: White and gray are used to indicate a neutral wire. White is the color most often used for this function. A neutral wire connects to the neutral bus bar within an electric panel. White and gray connect only to white and gray.
Green: Green indicates the grounding of an electric circuit. A green wire can connect only to another green wire and should never connect to any other color wire. Green wires connect to the grounding terminal in an outlet box and run from the outlet box to the ground bus bar within an electric panel. The purpose of the green wire is to provide a path to ground for a circuit's electric current if a live wire within the circuit happens to touch metal or some other conductive material.
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