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Electrical Wire Color Meaning


The color of the sheath or insulation that surrounds the wires are used as a standard in the US. The displayed insulation color is an indication of what is carried on that wire:

  • Black – The live or hot wire. Sometimes it is red instead of black.

  • White – The neutral wire. Sometimes it is brown instead of white.

  • Green or green/yellow, also bare copper – The ground wire.

Remember that even a neutral wire passes electricity and so do you. Always turn off your circuit breaker and light switch prior to working on any electrical installations.

If you are installing lights with a dimming option, you will see two sets of wires: the three listed above and then another pair of wires to connect your compatible dimmer. Some fixtures may include a purple wire as the live wire for your dimmer. Always refer to the installation manual and to your dimmer manufacturer’s installation details to see how to safely connect your dimmer and light fixture. If you have questions about your specific wiring and dimmer, please consult with a qualified electrician.

2 Comments

  • We have done wiring a 3-core wire (black, white and green) to a 2-core wire (black & white) by cutting out the green wire flush at the exit. But we have not done it to a 4-core wire. What is the fourth wire (Red) for?

    Tim on
  • Is it possible to hook together a three wire, black,white and green, to a four wire, black, white, red and bare?

    Roger on

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