Electrical Wire Color Codes
Electrical & Wiring · 13 specs
Direct Answer
AC electrical wiring color codes distinguish Line (hot), Neutral, and Ground conductors, standardized in the US under NEC (120/240V Black/Red/White and 277/480V Brown/Orange/Yellow) and internationally under IEC 60446 (Brown/Black/Grey Line, Blue Neutral, Green-Yellow Ground).
Source: NFPA 70: National Electrical Code / IEC 60446 / BS 7671 · Last reviewed Aug 28, 2026
Specs
| Governing Standards | NEC Article 200/250 (US) / IEC 60446 / BS 7671 (Europe/UK) |
| US 120V / 240V Phase A (Hot) | Black |
| US 120V / 240V Phase B (Hot) | Red |
| US 120V / 208V Phase C (Hot 3-Phase) | Blue |
| US 120V / 240V Neutral | White (Continuous white or gray outer finish per NEC 200.6) |
| US 277V / 480V Commercial 3-Phase (Wye) | Phase A: Brown | Phase B: Orange | Phase C: Yellow | Neutral: Gray (conventional scheme; this is a symmetrical wye system with no high-leg condition) |
| US 120V / 240V High-Leg Delta (4-Wire, 3-Phase) | Phase A: Black | Phase B: Orange (NEC 110.15-mandated high-leg marking, ~208V to neutral) | Phase C: Blue | Neutral: White |
| US Protective Earth / Ground | Bare Copper, Green, or Green with Yellow Stripe |
| IEC / Europe Phase 1 (L1) | Brown |
| IEC / Europe Phase 2 (L2) | Black |
| IEC / Europe Phase 3 (L3) | Grey |
| IEC / Europe Neutral (N) | Blue (Light Blue) |
| IEC / Europe Protective Earth (PE) | Green with Yellow Stripe (Bi-color mandate) |
US NEC vs International IEC 60446 Wire Color Comparison
| Function | US Residential (120/240V Split-Phase) | US Commercial (277/480V 3-Phase Wye) | European Union / IEC 60446 | UK Pre-2004 Harmonization |
|---|---|---|---|---|
| Phase 1 (Line 1 / Hot) | Black | Brown | Brown | Red |
| Phase 2 (Line 2 / Hot) | Red | Orange | Black | Yellow |
| Phase 3 (Line 3 / Hot) | Blue | Yellow | Grey | Blue |
| Neutral (Grounded) | White | Gray | Blue (Light Blue) | Black |
| Ground (Protective Earth) | Bare / Green | Green | Green-Yellow | Green-Yellow |
Note: the orange 'high-leg' marking is a separate NEC 110.15 requirement that applies specifically to 120/240V, 4-wire, 3-phase delta services (where one phase reads ~208V to neutral) — it is not part of the 277/480V wye scheme above, which has no high-leg conductor.
The Danger of Transatlantic Color Code Mismatches
Cross-border equipment installation carries extreme hazard due to the 2004 European Harmonization (BS 7671 / IEC 60446):
- The Black Wire Reversal: In the United States, Black is Live/Hot (120V) and Blue is 3-phase Hot. In modern European wiring, Black is Line 2, but in legacy UK wiring (pre-2004), Black was Neutral. Connecting an imported US fixture assuming black is neutral results in an energized live chassis.
- The Blue Wire Reversal: In the US, Blue is an energized 3-phase Line conductor. In Europe, Blue is Neutral.