Electrical wire color code: what the NEC requires and what is convention
Published Sep 30, 2026
The NEC only fixes the colors of two conductors: the grounded conductor (the neutral in most systems) and the equipment grounding conductor. Everything else is convention, local amendment or the owner's spec. Knowing which is which saves arguments at inspection.
What the NEC requires
| Conductor | Required identification | Where in the NEC |
|---|---|---|
| Grounded conductor (neutral) | White or gray insulation, or three continuous white or gray stripes on another color other than green | 200.6(A) |
| Equipment grounding conductor | Bare, green, or green with one or more yellow stripes | 250.119 |
| Ungrounded (hot) conductors | Any color except white, gray or green | 310.6(C) and 200.7 |
| High leg of a 4-wire delta | Orange, or another effective marking, at every point where the neutral is also present | 110.15 and 230.56 |
Larger sizes can be re-marked. A grounded conductor 4 AWG and larger may be identified at each termination with white or gray tape or paint instead of colored insulation (200.6(B)). An insulated equipment grounding conductor 4 AWG and larger may be re-identified with green tape or paint at each end and wherever it is accessible (250.119(A)). That is why large feeders are often all black.
Posting is required. Where a building has branch circuits from more than one voltage system, NEC 210.5(C) requires the identification method for each system to be documented and posted at each panelboard, or otherwise made available.
The common conventions
These are not in the NEC, but they are what most electricians and many specs expect.
| System | Phase A | Phase B | Phase C | Neutral | Ground |
|---|---|---|---|---|---|
| 120/240 V single phase | Black | Red | White | Green or bare | |
| 120/208 V three phase | Black | Red | Blue | White | Green or bare |
| 277/480 V three phase | Brown | Orange | Yellow | Gray | Green or bare |
A few details:
- White on 120/208 V and gray on 277/480 V keeps the two neutrals apart in a building that has both.
- Some jurisdictions and owners write these conventions into their own rules. Check the local amendments and the project spec.
- Orange is phase B on 277/480 V by convention, and the NEC marking for the high leg of a 120/240 V four-wire delta (orange or another effective marking, 110.15). Confirm what the building already uses before you add circuits.
Switch legs, travelers and DC
- Switch legs are often red or black. A white conductor in a cable can be used as a switch loop feed only if it is re-identified and it supplies the switch, not the return (200.7(C)(1)).
- Three-way travelers are commonly red and black in 14/3 or 12/3 cable, or any agreed pair in conduit.
- For DC systems such as PV and battery circuits, NEC 210.5(C)(2) and Article 690 cover polarity identification. Red for positive and black for negative is common, but follow the posted scheme.
Buying by color
THHN/THWN-2 in the smaller sizes (14 AWG to about 2 AWG) is sold in a full range of colors, so you can wire to the convention without tape. Larger sizes are usually stocked in black, and the neutral and ground are re-identified with tape at the ends.
Shop THHN in every color
- 14 AWG THHN/THWN-2, 12 AWG and 10 AWG
- 8 AWG and 6 AWG
- Bare copper for grounding
- All colors in copper building wire
Verify with your local code. Color rules beyond the NEC minimum are set by local amendments and project specifications. Your inspector and the posted identification at the panel are the final word.