Wire colors
Name the conductor from its color. Get 10 right to finish.
On a US job, what is the green conductor?
The two systems side by side
| Conductor | US (NEC) | IEC 60445 (Europe) |
|---|---|---|
| Neutral | White or gray (required) | Blue |
| Ground / protective earth | Green, green-yellow or bare (required) | Green-yellow |
| Phase 1 | Black or brown (common practice) | Brown |
| Phase 2 | Red or orange (common practice) | Black |
| Phase 3 | Blue or yellow (common practice) | Grey |
Watch out for blue and black: in the US they are hot conductors, under IEC blue is the neutral and black is phase L2. Always check which system a building or machine was wired to.
Questions
- What color is the neutral wire?
- In the US, white or gray (NEC 200.6). Under IEC 60445, used across Europe, blue.
- What color is the ground wire?
- In the US the equipment grounding conductor is green, green with yellow stripes, or bare copper (NEC 250.119). Under IEC 60445 the protective earth is green-yellow.
- Does the NEC set the colors for phase wires?
- No. It only reserves white, gray and green. Black, red and blue (208Y/120 V) and brown, orange and yellow (480Y/277 V) are common practice, not code rules.
Explained in our own words and checked against several references. For the full rules, see the NEC (NFPA 70), NFPA 79, IEC 60617, IEC 60445 and IEC 81346-2. Your drawing legend always comes first.