Black, white, green, red, blue, orange, brown, and gray. The color of the insulating sheath on the outside of the wire usually has its own meaning. Therefore, when you are fiddling with a new light fixture, in addition to turning off the circuit breaker, you must also determine the meaning of each colored wire you will encounter next.
At the beginning of the electricity consumption in the United States, there was no systematic color coding, or even a set of standards for correct use. In 1879, shortly after Edison first introduced electric lights, the insurance industry began issuing safety guidelines. The first set of official guidelines appeared in 1881 and included addressing capacity, insulation and installation. But there is no classification of wire colors.
