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Wire colors & phases
The US electrical color code at a glance — how to tell hot from neutral from ground, and how the phases are marked in single- and three-phase systems.
Back to AstralLearnSingle-phase 120/240V
Most homes
- Hot — L1 — Black
- Hot — L2 — Redthe second hot in 240V circuits
- Neutral — White
- Ground — Green/baregreen, green-yellow, or bare copper
Three-phase 208Y/120V
Light commercial
- Phase A — Black
- Phase B — Red
- Phase C — Blue
- Neutral — White
- Ground — Green/bare
Three-phase 480Y/277V
Commercial / industrial
- Phase A — Brown
- Phase B — Orange
- Phase C — Yellow
- Neutral — Gray
- Ground — Green/bare
What the NEC actually requires: only two colors are mandated — the grounded (neutral) conductor must be white or gray, and the equipment ground must be green, green-with-yellow, or bare. The hot colors above are the common convention, not a blanket NEC rule; what matters is that hots are clearly distinguishable and consistent throughout the building.
The high-leg rule: on a 120/240V high-leg (delta) system, the phase with the higher voltage to ground (~208V) must be marked orange — NEC 110.15. That's why orange is avoided for a normal phase where a high leg could exist.
Identifying a circuit: check voltage (120 vs 240 vs 208 vs 480), how many hots (one = 120V, two = 240V single-phase, three = three-phase), whether there's a neutral, and always the ground. A labeled panel directory makes it obvious — and is required by code.
Educational reference — verify against the current NEC and your AHJ. Work that has to pass inspection? Call a licensed C-10 → (650) 562-8594.
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