What the Wire Colors Mean
Wire color tells you the job each conductor does, and getting it right is a safety essential. In standard 120-volt and 240-volt residential wiring in the United States, the colors follow a consistent convention. The code is strict about the neutral and ground colors, while hot conductors simply have to be a color that is not reserved for neutral or ground.
The Standard Residential Color Code
| Color | Function |
|---|---|
| Black | Hot (ungrounded), the most common hot conductor |
| Red | Hot (second hot in 240-volt circuits, or a switch leg) |
| Blue and Yellow | Hot, often used as travelers or additional hots in conduit |
| White or Gray | Neutral (grounded conductor) |
| Green or Green with Yellow Stripe | Equipment ground |
| Bare Copper | Equipment ground |
Hot Conductors
Black is the standard hot in most circuits. Red commonly serves as the second hot leg in a 240-volt circuit, the traveler between three-way switches, or a switched leg for a light. In conduit work, blue and yellow are also used as hots so each conductor can be told apart.
Neutral and Ground
White or gray is always the grounded neutral, which carries current back to the panel. Green, green with a yellow stripe, or bare copper is the equipment grounding conductor, which provides a safe fault path and normally carries no current. These two color rules are required by code and should never be repurposed.
The White Wire Exception
In some older or specific wiring situations, a white conductor inside a cable is used as a hot, such as in a switch loop. When that happens, the code requires the white conductor to be re-identified at both ends with black or red tape or marking so the next person knows it is energized. If you see a white wire wrapped in colored tape, treat it as hot.
Code and Safety Note
Always treat any conductor as live until it is tested and confirmed de-energized, since colors can be mislabeled in older work. Follow the National Electrical Code and local amendments, confirm with your authority having jurisdiction, and use a licensed electrician for wiring connections.
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