What Are Wiring Colors?

In alternating current (AC) and direct current (DC) powered circuits, different wiring colors are used to identify the purpose of individual wires. Some jurisdictions require all wiring colors of a powered circuit to be disclosed in legal documents, whereas others may only color code some of the wires.

Different countries have electrical codes governed by their own regulatory bodies, so the meaning of different colored wires may differ from country to country. The United Kingdom follows the codes of the International Electrotechnical Commission, the United States uses the US National Electrical Code and Canada has adopted the Canadian Electric Code.

Although different countries follow their individual electrical codes, their color coding is, for the most part, consistent with that of the United States. Five main colors are used to identify wires, which are green or green/yellow, white, black, red and blue. Some countries may also use brown, orange, yellow and gray as part of their wiring schematics. The green or green/yellow wire is used for the protective ground. White wiring is used to identify a neutral wire. A line or single-phase wire is identified with black or red wiring, depending on the country, and three-phase lines are usually identified with black, red and blue wires.