Electrical Wire Color Code: Hot, Neutral & Ground (US + International)

In US residential wiring under the NEC, black and red wires are hot, white or gray is neutral, and green or bare copper is ground.

Quick answer: hot, neutral and ground colors (US)

Wire color codes are set by the wiring standard used in each country: the NEC (NFPA 70) in the United States, the CEC in Canada, BS 7671 in the UK, IEC 60445 across the EU, and AS/NZS 3000 in Australia and New Zealand. The NEC only fixes the colors of the neutral (white or gray) and the ground (green, green-yellow, or bare) — any other color may legally be a hot conductor.

US residential wire colors (120/240 V)

In US residential wiring, the black wire is hot — it carries 120 V relative to neutral. The red wire is a second hot conductor, used for the other leg of a 240 V circuit, for three-way switch travelers, and for interconnect wiring on smoke alarms. The white wire is the neutral: the grounded return conductor required by NEC 200.6 to be white or gray. The green, green-with-yellow-stripe, or bare copper wire is the equipment grounding conductor (NEC 250.119) and carries no current in normal operation.

On a 240 V circuit the black and red conductors are both hot, with 240 V between them and 120 V from either one to the neutral. That is why a dryer or range cable contains black, red, white, and green (or bare) conductors:

US commercial wire colors (277/480 V)

In US 277/480 V commercial and industrial systems, the standard convention is brown, orange, and yellow for the three phases, with a gray neutral. The NEC does not mandate phase colors — only neutral and ground colors are fixed by code — but where a building contains both voltage systems, NEC 210.5(C) requires each system’s conductors to be identified consistently, and brown-orange-yellow versus black-red-blue is the near-universal split.

Warning — orange means high-leg delta: on a 120/240 V three-phase four-wire delta service, NEC 110.15 requires the high-leg conductor to be marked orange. The orange high leg measures roughly 208 V to neutral, not 120 V — connecting a 120 V load between the high leg and neutral will destroy it. If you find an orange conductor in a panel, treat it as the high leg until proven otherwise.

DC wire colors (solar, battery, automotive)

In DC systems, red is positive (+) and black is negative (−). In automotive wiring the black conductor is the chassis-ground negative, and in marine DC systems (ABYC) yellow is often used for the negative instead of black so it cannot be confused with AC hot wiring. In a grounded two-wire or three-wire DC system, the grounded conductor (often the center tap or negative) must be white or gray, just as in AC work.

Solar PV array wiring is typically run in single-conductor PV wire or USE-2 where red (or another color) marks positive and black marks negative; modern transformerless (ungrounded) PV systems have no white grounded conductor on the DC side. Always confirm polarity with a meter before landing DC conductors — reversed polarity can destroy charge controllers and inverters.

International wire color codes (UK, EU, Canada, Australia, and more)

In the UK and EU, the brown wire is live, the blue wire is neutral, and the green-and-yellow striped wire is earth. UK wiring installed before 2004 used red for live and black for neutral — the harmonised brown/blue colours were introduced into BS 7671 in 2004 and became mandatory for new work on 31 March 2006. Canadian wire colors under the CEC match US practice: black or red hot, white neutral, green or bare ground. In Australia and New Zealand (AS/NZS 3000), flexible cords use brown for active and blue for neutral, while older fixed wiring commonly used red for active and black for neutral.

Three-phase color codes follow the same split: modern IEC/UK installations use brown, black, and grey for L1/L2/L3, pre-2004 UK three-phase used red, yellow, and blue, US 120/208 V systems conventionally use black, red, and blue, and US 277/480 V systems use brown, orange, and yellow.

Wire color traps that cause shocks

The white wire is sometimes hot. In US cable wiring, the white conductor of a 2-wire cable may legally carry line voltage — most often in a switch loop, where it brings the hot feed down to the switch, or as the second hot of a straight 240 V circuit. NEC 200.7 requires that white conductor to be permanently re-identified as hot (black tape, paint, or other effective marking) at every location where it is visible. Older installations often skip the tape — never assume a white wire is neutral.

Black means opposite things in old UK wiring and new UK/EU wiring. In a pre-2004 UK installation, black is the neutral; in harmonised (post-2004) wiring, black is a live phase conductor in three-phase work and blue is the neutral. A UK property extended across the changeover can contain both meanings of black and both meanings of blue in the same building — such installations are required to carry a warning notice at the consumer unit stating that two colour versions of BS 7671 are present.

Orange can be a 208 V high leg. As covered above, NEC 110.15 reserves orange for the high leg of a 120/240 V delta system — 208 V to neutral where you might expect 120 V.

Never rely on wire color alone. Colors fade, previous owners miswire, tape falls off, and cable manufactured for one market gets installed in another. Treat color as a hint, not proof: verify every conductor with a non-contact voltage tester or a multimeter (proven on a known live source first), and confirm circuits are dead at the point of work before touching anything.

Safety note

This page is educational reference material, not an installation instruction. Fixed electrical installation work must be carried out by a licensed electrician in accordance with the applicable local wiring code — NEC/NFPA 70 in the US, CEC in Canada, BS 7671 in the UK, AS/NZS 3000 in Australia and New Zealand, or IEC 60364-based national rules elsewhere. Before working on any circuit, switch off and lock out the supply, then verify the circuit is dead with a voltage tester that you have first proven on a known live source. Wire colors identify conductors only when the original installer followed the rules — the tester, not the color, is the final word.

Frequently asked questions

Is the black wire hot or neutral?

In US and Canadian wiring, a black wire is always hot (live) — it is never a neutral, because NEC 200.6 reserves white and gray for the neutral. Watch for the reverse trap in old UK wiring, where black was the neutral color before 2004.

What color is the neutral wire?

In the US and Canada the neutral wire is white or gray (NEC 200.6). In the UK, EU, and Australia/New Zealand the neutral is blue; UK installations wired before 2004 used black for neutral.

Which wire is hot if both are black?

Do not guess — identify the hot with a non-contact voltage tester or a multimeter measured to a known ground. On two-conductor lamp (zip) cord, the smooth conductor is hot and the ribbed or striped conductor is neutral. Faded insulation and missing re-identification tape make color unreliable in old work, so always test before touching.

What do wire colors mean in the UK/EU?

Under BS 7671 harmonised colours (mandatory in the UK for new work since 31 March 2006) and IEC 60445 in the EU: brown is live, blue is neutral, and green-and-yellow is the protective earth. Three-phase circuits use brown, black, and grey. UK wiring installed before 2004 used red for live and black for neutral.

Is the white wire ever hot?

Yes. In US cable wiring the white conductor can carry line voltage in a switch loop or as the second hot of a 240 V circuit. NEC 200.7 requires it to be permanently re-identified as hot — black tape, paint, or marking — wherever it is visible, but older installations often skip this, so always test a white wire before assuming it is neutral.

What color is the ground wire?

In the US and Canada the equipment grounding conductor is green, green with one or more yellow stripes, or bare copper (NEC 250.119). In the UK, EU, Australia, and most other IEC-aligned countries the earth wire is green-and-yellow striped.

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Last verified: 2026-07-10