In the U.S., the equipment ground is green, green with a yellow stripe, or bare copper—never white or gray, which mark the neutral.
Ground wire color in the United States: quick guide
Color tells you function. In American wiring, the protective path that trips breakers and bonds metal parts is the equipment grounding conductor. When that path is a wire, its jacket or covering follows a tight rule set. If it’s insulated, it’s green or green with one or more yellow stripes. If it’s not insulated, it’s usually bare copper. Those colors are reserved in premises wiring. They aren’t used for hot or neutral. That way, anyone opening a box can spot the ground at once and keep devices safe during service.
| Conductor type | Allowed colors | Notes |
|---|---|---|
| Equipment grounding conductor (EGC) | Green; green/yellow stripe; bare copper | Reserved for grounding only in premises wiring |
| Grounded (neutral) conductor | White; gray; three white or gray stripes | Never green; carries return current in normal use |
| Ungrounded (hot) conductor | Any color except green, white, or gray | Common: black, red, blue; orange marks high-leg delta |
| Bonding jumpers | Green; green/yellow stripe; bare copper | Ties metal parts together for a solid fault path |
| Metal raceway as EGC | Not a color | EMT, IMC, rigid, and listed cable armor can serve as the path |
| Flexible cords (cord sets) | Green/yellow stripe or green | Matches device ground screws and terminals |
These markings line up with hardware you already know. Device ground screws are green. Ground terminals on receptacles are green. Cords with a green/yellow conductor land on the round pin. When every piece points the same way, installation goes quicker and testing makes sense.
Why neutral and ground aren’t the same
Neutral and ground live in the same box, yet they do different jobs. The neutral, marked white or gray, is a current carrier back to the source. The ground only carries current during a fault. That difference is why the neutral must never be used as a substitute for the ground on receptacles or fixtures. Using the wrong color for either can hide bootlegs and other unsafe tricks. Correct colors help you spot problems fast and wire repairs the right way.
Color rules for the neutral come from NEC 200.6. Ground color comes from NEC 250.119. Both aim to make identification plain even in tight spaces.
What color is ground wire in US homes: rules and tips
Open a typical junction box and you’ll see a bare copper pigtail twisted with other bare grounds. That’s normal in NM-B cable runs. Inside conduit, electricians often pull a green insulated wire for the ground so it stands out against black and red hots. On device yokes and fixtures, the ground terminal is green. Green screws match green wires; it’s built to be clear. Where a cable has a green/yellow stripe, that’s also a ground. You’ll see that pattern on many cords and imported devices.
In remodeling work you may run into odd colors in old cloth cable or re-marked conductors. Don’t guess. Kill power, separate conductors, and test with a two-pole tester. If a white wire has been re-purposed as hot, it should be marked at the ends with tape or sleeving. A ground that isn’t green, green/yellow, or bare is a red flag and calls for correction to today’s marking rules.
Where the code makes rare exceptions
There are a few special cases. Traffic signal systems can use green as an ungrounded signal conductor between certain heads under a tightly scoped rule, and the cable must still include a separate equipment ground. That carve-out exists so signal techs follow a long-standing pattern in that niche. Outside that slice, green and green with yellow stripe stay locked to grounding duty.
Can you re-identify a conductor as a ground?
It depends on size and cable type. For small conductors pulled in raceway, the ground must be green, green/yellow, or bare out of the box. For larger sizes and for some multi-conductor cables, permanent re-marking at the ends with green paint, tape, or sleeves is permitted, as long as the marking is durable. The goal is the same: anyone opening the equipment can tell the ground from the rest at a glance.
Metal raceway as the grounding path
Not every branch circuit needs a separate green wire. Continuous metal raceways such as EMT, IMC, or rigid conduit qualify as the equipment grounding conductor when installed with tight joints and listed fittings. Many jurisdictions allow that method for commercial runs where steel conduit is common. In those cases, you still bond the metal box and device yoke so any fault rides the metal back to the service equipment and trips the breaker fast.
Flexible cords, plugs, and appliances
On cord caps and cord sets, the ground is the green or green/yellow conductor that lands on the green screw. The flat blades carry hot and neutral; the round pin is the ground. That color pattern follows UL and IEC norms, so it looks the same on many imported appliances. If you’re wiring a replacement plug, match green to green, white to silver, and hot to brass. If the cord has only two conductors, there’s no ground in that cord at all, and the tool or lamp is built with double insulation instead.
Homes, shops, and different systems
Most houses run 120/240-volt split-phase. Small branch circuits use black as hot, white as neutral, and green or bare as ground. Shops with three-phase service often add blue as a hot in conduit runs. In older high-leg delta panels, the high leg is marked orange. None of that changes the reserved colors for the ground and neutral. Green stays ground, white or gray stays neutral, and no other color may take those roles in premises wiring.
How to trace and label safely
Before working in a box, shut off the right breaker and verify with a tester you can trust. Pull devices gently, keep conductors separated, and tag each one as you identify it. Bond metal boxes with a grounding clip or a green pigtail under a listed screw. On receptacles, land the green or bare wire on the green terminal, tie neutrals under the silver screws, and land hots on brass. If the box is plastic, bond the device only. If it’s metal, bond both box and device so faults can’t sneak past.
Common mistakes to avoid
- Using white or gray as a ground. That’s the neutral color, not ground.
- Painting a random spare as green on small gauge conductors that must be factory green.
- Tying neutral and ground together on a receptacle or in a subpanel.
- Failing to bond a metal box or fixture strap.
- Assuming a bootleg ground will pass a tester; cheap testers can be fooled.
Do’s and don’ts cheat sheet
| Task | Connect the ground to | Notes |
|---|---|---|
| Replace a receptacle | Green screw on the device | Bond the metal box with a pigtail if present |
| Install a metal light box | Grounding screw or clip with pigtail | Also bond the fixture strap if required |
| Pull conductors in EMT | Green insulated or rely on the raceway | Use listed fittings and tight couplings |
| Wire a 3-prong plug | Round pin to green or green/yellow | Match white to silver and hot to brass |
| Swap a switch loop | Bond the metal box and the yoke | Don’t land a ground under a terminal with another conductor |
| Upgrade an old two-wire circuit | New cable with ground back to the panel | Or add a GFCI and label when permitted |
Old wiring and special cases
In vintage homes you may see armored cable where the steel jacket serves as the grounding path. That method is still recognized when the armor type is listed for grounding duty. If in doubt, pull a green pigtail from the box bonding means to the device. Knob-and-tube has no ground at all; upgrades call for new cable or a code-permitted GFCI approach with labels. Some low-voltage and signal systems follow their own color traditions. Those don’t change the house wiring colors. Keep systems separate and avoid mixing conductors from different codes in the same raceway.
Practical testing habits
A simple three-light tester can spot open grounds and reversed polarity, yet it can’t see through a bootleg ground. Use a two-pole tester or a meter to read hot-to-neutral and hot-to-ground. Readings should match. If hot-to-ground reads low, the path is weak. If neutral carries current on metal raceways, look for loose neutrals or crossed bonds. Log your readings on tricky circuits so the next visit starts faster.
Why the colors are reserved
Green and white carry meaning across trades and gear makers. The green family tells you “safety path.” White and gray tell you “grounded circuit conductor.” That shared language cuts errors during service and lets inspectors read a job quickly. The rules also prevent mixed signals where a green wire could land on a hot lug and shock whoever opens the panel next week. Clear, consistent colors save time and reduce risk across the board.
Where to verify the rules
If you need chapter and verse, the OSHA guide to electrical hazards summarizes common colors used in the U.S. The exact marking rules live in the National Electrical Code. You can read the neutral ID rule in NEC 200.6 and the grounding color rule in NEC 250.119. These sources give you the exact language that inspectors and pros use every day.
Bottom line for color and safety
In the United States, a ground wire that’s part of a branch circuit or feeder is green, green with a yellow stripe, or bare copper. Neutrals are white or gray. Hots are anything else. Keep those three lanes straight, bond metal parts with care, test before you touch, and your devices will clear faults fast and stay quiet in daily use.