Wire Color Codes
The NEC does not assign required colors to ungrounded (hot) phase conductors in general. The conventions below are common U.S. trade practice. Always identify conductors by terminal, marking, and testing — not by color alone. The Code does require certain colors or markings for grounded conductors, equipment grounding conductors, and a high-leg.
What the NEC actually mandates. Grounded (neutral) conductors: 200.6 — generally white or gray, or three continuous white stripes, with size and re-identification rules in 200.6 and 200.7. Equipment grounding conductors: 250.119 — bare, green, or green with one or more yellow stripes (and the usual re-identification rules). A high-leg (wild-leg) on a 4-wire delta must be orange or marked orange where the midpoint of one winding is grounded (110.15). Other phase colors are convention, not a Code color law.
Common 120/240 V single-phase (and split-phase services)
| Function | Common color | Notes |
|---|---|---|
| L1 (ungrounded) | Black | Convention |
| L2 (ungrounded) | Red | Convention |
| Grounded (neutral) | White or gray | 200.6 |
| EGC | Green, green/yellow, or bare | 250.119 |
Common 208Y/120 V three-phase
| Function | Common color | Notes |
|---|---|---|
| Phase A | Black | Convention |
| Phase B | Red | Convention |
| Phase C | Blue | Convention |
| Grounded (neutral) | White or gray | 200.6 |
| EGC | Green, green/yellow, or bare | 250.119 |
Common 480Y/277 V three-phase
| Function | Common color | Notes |
|---|---|---|
| Phase A | Brown | Convention |
| Phase B | Orange | Convention — do not confuse with a 240 V high-leg |
| Phase C | Yellow | Convention |
| Grounded (neutral) | Gray (or white) | 200.6. Where both 120/208 and 277/480 are present, many shops keep 208 neutrals white and 480 neutrals gray so the systems stay distinct — still a convention, and 200.6 must be met. |
| EGC | Green, green/yellow, or bare | 250.119 |
High-leg (wild-leg) 120/240 V 4-wire delta — 110.15
On a 4-wire delta with the midpoint of one winding grounded, the phase with the higher voltage to ground (typically about 208 V to neutral) must be orange or marked orange. That conductor is commonly landed on the “B” phase (center) of a panel, but the required identification is the orange marking, not the bus position. Confirm with a meter: the high-leg to neutral is the ~208 V reading.
Switch-leg / traveler / switched-neutral colors vary by shop and are not Code-assigned. Re-identified conductors must follow 200.7 and 250.119. Isolated-ground and isolated-phase applications have additional rules. When in doubt, megger-safe continuity and voltage tests beat color.
Reference only — not engineering, legal, or code-compliance advice. Results are estimates for qualified persons and must be verified against the NEC edition adopted where the work is done (your selected edition), manufacturer instructions, and the local AHJ. Use is subject to the Terms of Use & Disclaimer. — Morningstar Electric LLC