Author Topic: Meanings of black white and bare copper wire?  (Read 49914 times)


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Meanings of black white and bare copper wire?
« on: January 15, 2012, 04:42:11 PM »
Caution:  the meaning of these colors in the electrical wiring of your home may not necessarily be how your electrical wiring was installed.  The use of a auxiliary black or white wire to carry , jump, or connect a fixture, outlet, switch or motor, could have been installed as a convenience of the available wire.  This doesn’t mean the wiring is wrong and will fail this only means the color coding procedure was not followed.

Black, White, and Bare Copper are industry standards and the meanings of these colors are as followed:

Black – is the power or current which carries the load and is a live wire.  In the Break box it is isolated and dedicated to the breaker in which it applies to.

White – is a common wire and is a live wire which returns connection of current to complete the circuit.  In the breaker box it is connected to a common wire connection assembly which usually the breaker switch prods in modern breaker boxes will share.

Bare Copper – Most mistake the importance of this wire, it is the “Earth” or commonly known as ground wire, in which carries the current to earth and usually will cause a breaker to trip and cut off the circuit to prevent fire or continued shock.  You will notice this wire attaches to metal boxes and fixture housing, and the other end is connected to the breaker box ground/Earth wire, which is connected to a metal stake 4’ to 6’ in the ground.  Your metal plumbing and roofing may also be connected to this system.  If not for this wire and the white and black wires were to touch metal the wire would heat up and possibly start a fire.

Addition wire colors could be found and the meanings are as followed:

Red – a second power/current wire usually for a light at a ceiling fan which commonly connects to a blue wire at the fixture allocated for the light.  Can also be found at 220 volt outlets where 110v times 2 = 220v or a black and a red feeding separate prods.

Blue - is usually located in a fixture and represents a power/current connection for a light, which would connect to a red wire if available or the black wire if not.  In a ceiling fan the blue and black wire coming from the fan would connect to the black live wire from the house outlet.  Using this configuration means they share the same switch or current.

Green – is a color that shares the Bare Copper and is a ground wire. (Earth) Connecting green to Bare Copper.

Note: These color rules are only as good as the person who follows them.  I have known people to intentionally alter these from a foreclosure to cause fault and damage to the future buyer.  Really a scary thought so use your proper due diligence.  More importantly than the colors of the wire is the gauge and load rating for the wire?  If you have to ask what is this then you may want to consider hiring an electrician to do the work.  Improperly gauged wire use in the wrong application can certainly cause a fire.  Using too thin of a wire on something like a water heater will cause a fire, because the breaker would be 30-50amp and the wiring would be rated for 15amp, if a load of 30amps passes through the wire it will melt, which will be molten metal or arching and in contact of flammable material would burn.

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