In U.S. wiring, a grounding conductor is green, green with yellow stripes, or bare copper; white or gray is the grounded neutral, not ground.
Getting the ground wire color right isn’t cosmetic—it keeps people safe and helps every electrician read a circuit the same way. In the United States, the equipment grounding conductor (EGC) has a dedicated look that sets it apart from hot and neutral. This guide lays out the colors that are allowed, the few edge cases, and simple checks that stop mix-ups in panels and junction boxes.
Proper Color Code For Ground Wire In USA: Quick Rules
Here are the plain rules used on job sites coast to coast:
- Ground wire color: green, green with one or more yellow stripes, or bare copper.
- Neutral (grounded conductor): white or gray only; never use these for ground.
- Hot (ungrounded conductors): any color except green, green/yellow, white, or gray.
- Inside cable like NM-B: the ground is usually bare copper; in conduit, the ground is often green THHN/THWN.
- For large conductors (4 AWG and up), you may re-identify a wire as ground at each end with green tape or labels.
- Never re-mark a white or gray conductor as ground; those colors are reserved for the grounded conductor.
| Function | Permitted Colors | Code Pointer |
|---|---|---|
| Equipment grounding conductor | Green, green/yellow, or bare copper | NEC 250.119; OSHA 1910.305 |
| Grounded conductor (neutral) | White or gray | NEC 200.6 |
| Ungrounded conductors (hot, line) | Any color except green, green/yellow, white, gray | NEC 250.119; 200.6 |
What The National Electrical Code Says
NEC 250.119 sets the identification for an equipment grounding conductor. If the wire is insulated, its jacket must be green or green with yellow stripes. A bare copper equipment ground also meets the rule. NEC 200.6 reserves white and gray for the grounded conductor, so those are off-limits for ground.
For flexible cords and cords on portable gear, OSHA’s wiring section requires that the equipment ground be distinguishable from other conductors. Pair that with the NEC colors above and you’ve got a consistent, readable scheme from panel to plug. That clarity saves time.
Code Links
See OSHA 1910.305 and NEC 200.6 reserving white or gray for the grounded conductor.
Ground Wire Colors You Can Use
On residential NM-B cable, you’ll almost always see a bare copper ground. In MC, AC, or in raceway, designers often pull a green THHN or THWN. Green with yellow stripes shows up in industrial panels and packaged equipment, and it’s fully acceptable in buildings as well.
Bonding jumpers follow the same color logic. The goal is simple: every conductor that ties equipment to the grounding path stays obvious at a glance.
Re-Identifying A Conductor As Ground
For 4 AWG and larger, the Code lets you re-identify a conductor as an equipment ground. Mark it at each end and at any point the conductor is accessible by wrapping green tape, using green sleeving, or applying green adhesive labels. This is common in big feeders where a spare conductor is available. By contrast, 6 AWG and smaller must be manufactured green or be bare; tape won’t satisfy the rule on those sizes. Also, a white or gray conductor can’t be turned into a ground by re-marking—it stays a grounded conductor by rule.
| Conductor Size / Type | Can It Be Re-Marked As Ground? | How To Mark |
|---|---|---|
| 4 AWG or larger, insulated | Yes | Green tape, sleeve, or labels at ends and access points (NEC 250.119) |
| 6 AWG or smaller, insulated | No | Must be factory green or green/yellow |
| Any size, bare copper | Already ground | No marking required |
What Not To Do
Don’t use green, or green with yellow stripes, for any hot or neutral. Don’t re-tag a white or gray wire as ground. Don’t rely on a paper diagram to identify a conductor in the field; wires need visible identification on the jacket or at their terminations. And don’t assume shade equals function: paint and overspray don’t count as a legal marking.
Special Systems And Panels
Whether you’re working on AC or DC, rooftop PV, battery systems, or an EV charger, the equipment ground keeps the same appearance: green, green/yellow, or bare. Control panels built to UL 508A and many machine standards use the same protective-conductor colors, so a tech opening a cabinet sees the ground instantly. Inside a metal raceway, the metallic raceway may serve as the path, but pulled green conductors are common because they’re easy to verify during maintenance.
Field Tips That Prevent Mix-Ups
• Strip back enough jacket at terminations so the green or bare ground is obvious without guesswork.
• In old work, clean tarnish on bare copper grounds so they aren’t mistaken for aluminum.
• When a factory pigtail is green/yellow and your pulled ground is solid green, keep the connection tidy and visible with a short length of green heat-shrink over the splice.
• Label long bonding jumpers near both ends; text like “EGC” or “BOND” adds clarity during troubleshooting.
• When you cap off unused conductors in a multi-wire pull, don’t ever park them on a green screw.
Keep colors consistent across panels and raceways. Train crews to follow the same markings. Record changes clearly.
Common Scenarios And Clear Calls
Opening a junction box on NM-B? The bare copper is the ground. Installing a receptacle from a metal box on EMT? Use the metal raceway plus a green pigtail to the device yoke if required by local practice. Terminating in a motor peckerhead? Expect a green or green/yellow lead for the equipment ground from the manufacturer. Working in a 277/480V lighting panel? Neutrals are gray by tradition and code, and the equipment ground remains green or bare.
If you ever find a green conductor tied to a breaker, stop and correct the circuit. Green and green/yellow are reserved for the equipment grounding path.
Code Pointers And Where To Read Them
You can read the OSHA wiring section online, which requires the ground conductor in cords and general wiring to be clearly identifiable. For the NEC language on neutrals and the reserved colors for equipment grounds, check the identification rules quoted in Section 200.6 and Section 250.119 in current code resources.
Why Ground Color Consistency Matters
Color is the fastest way to read a circuit. When every site follows the same scheme, a technician can open an enclosure and find the bonding path in seconds. That cuts mistakes during lockout, testing, and service. A clear ground also helps torque checks go faster, since the green or bare conductor is easy to trace from device to equipment bar.
How Inspectors Read Your Work
Inspectors look for two things: correct function and clear identification. They’ll look for a green screw on devices bonded to a box, a visible ground in cables, and a proper termination on the equipment bar. If a conductor was re-identified as ground, they’ll look at each end for green tape or sleeves. If white or gray shows up on a grounding point, expect a correction notice.
Color Myths To Ignore
“Green with yellow stripes is only for Europe.” Not true; the NEC allows it and many U.S. factories use it. “Bare copper isn’t allowed.” Wrong; bare copper is allowed in building wiring and is common in NM-B. “Any shade of light gray is ground.” That mixes up neutral with ground; gray is a grounded conductor, not an equipment ground. “I can repaint a jacket and call it green.” Paint isn’t identification. Use sleeves, tape, or labels that encircle the conductor at the ends.
When A Sleeve Beats A Re-Pull
Large feeders often include an extra insulated conductor. If it’s 4 AWG or bigger, re-identify it as the ground with green sleeving rather than pulling new wire. Use heat-shrink for a durable, wipe-proof band. Place the sleeve so it remains visible after lugs are installed, and repeat at junction points where the conductor is accessible. On smaller sizes, order a true green conductor or use cable with a bare copper ground.
Quick Reference: Real-World Jobs
Replace A Switch In A Plastic Box
Bonding a plastic box isn’t required, so you’ll land the equipment ground on the device only. Use the green screw on the switch and a listed connector for the splice. If the cable ground is bare copper, trim cleanly and avoid nicking the conductor.
Install A Subpanel
Keep neutrals and grounds separate in the subpanel. Use a green bonding screw or strap only in the service disconnect enclosure, not in downstream panels. Pull a green equipment grounding conductor sized from NEC Table 250.122 or use a metallic raceway permitted for the fault path.
Add A 240-Volt Circuit
Two hots plus an equipment ground is the usual pull. Use black and red for the hots out of habit, keep the green equipment ground on the device yoke or equipment bar, and don’t bring a white unless the load needs a neutral.
Labeling And Documentation
Color doesn’t replace clear labels. Add circuit numbers at panel and device, tag long bonding jumpers, and keep a short note on re-identified conductors. That paper trail helps future crews, and it helps you pass turnover cleanly.