Electrical
Electrical conductor color code and phase identification field guide
Tell the phases, the neutral, and the ground apart the way the code and the trade do, mark what the NEC actually fixes, and verify the rest with a meter.
Direct answer
Conductor color code and phase identification is how each wire is marked so the next worker knows which conductor is a phase, the neutral, or the ground. The NEC fixes only the grounded conductor (white or gray), the equipment ground (green or bare), and the high-leg (orange). Phase colors are convention. The adopted code edition controls.
Key takeaways
- The NEC fixes only three conductors by color: neutral white or gray (200.6), equipment ground green, green-yellow, or bare (250.119), and the high-leg orange (110.15).
- Phase colors are convention, not NEC mandate: black-red-blue for 120/208V, brown-orange-yellow for 277/480V.
- At 6 AWG and smaller the neutral color must be in the insulation; at 4 AWG and larger, mark identification at the terminations.
- On multi-voltage jobs, NEC 210.5 and 215.12 require each phase identified by phase and system, with the scheme posted at each panelboard.
- Never trust color: test every conductor dead with a meter proven on a known live source before treating it as safe.
What conductor identification is and why it matters
Conductor identification is the marking that tells the next person which wire is which: which conductors are energized phases, which is the grounded neutral, and which is the equipment ground. The wire does not care what color it is. The person who opens the box six months from now does, because they are about to decide what is safe to touch and what is going to bite them.
A mis-identified conductor is a shock hazard and an equipment hazard at the same time. A neutral that someone used as a hot without re-marking it looks safe and is not. A ground tied to a phase because the colors got crossed turns the grounding path into a live conductor. The identification is the agreement that keeps the system readable, and a readable system is one the next worker can work on without guessing.
Two ideas run through everything below. The NEC fixes the identification of a few conductors and leaves the rest to convention. And color is the first clue, never the proof. Picking the right wire for the place is a separate question, covered in the companion conductor-types and wiring-methods guides. This one is narrower: telling the conductors apart once they are in the pipe.
What color is the neutral wire?
The grounded conductor, the neutral, is white or gray. The NEC at 200.6 requires a grounded conductor 6 AWG or smaller to carry a continuous white or gray outer finish, or three continuous white or gray stripes on insulation that is any color except green, along its whole length. Tape and paint do not count at that size. The color has to be in the wire.
Gray gets forgotten. White and gray are both legal grounded-conductor colors, and on jobs with more than one system the crew often runs white for one system's neutral and gray for another so the two neutrals do not get mixed in a gutter. That is a convention, not a mandate, but it is a good one.
The grounded conductor is not the same thing as the ground, even though both connect back to earth at the service. The neutral is a current-carrying conductor that completes the circuit. The equipment ground carries fault current only when something has failed. Calling the white wire the ground is how an apprentice tells you they have not sorted the two out yet.
The equipment grounding conductor: green, green-yellow, or bare
The equipment grounding conductor, the EGC, is green, green with one or more yellow stripes, or bare. The NEC at 250.119 sets that, and it runs the other direction too: a conductor that is green or green-with-yellow cannot be used as a phase or a neutral. Green is reserved. Once you see green, the code says that wire is a grounding conductor and nothing else.
Bare is fine for an equipment ground and common inside cables and in conduit on smaller work. Insulated green shows up where the ground shares a raceway with other insulated conductors and you want it covered.
The EGC is the conductor that has to work the day everything else has failed. A line-to-ground fault dumps current into it, and that current is what trips the breaker fast enough to clear the fault. Cross it with a phase, or leave it out, and the fault has no low-impedance path home, so the breaker may sit there while metal stays energized. That is the failure the green wire exists to prevent, which is why the code will not let any other conductor wear its color.
Is wire color code required by the NEC?
For the ungrounded conductors, the phases, the NEC does not mandate specific colors. This is the single most misunderstood point about wire color in the trade. There is no code line that says a phase has to be black, or red, or blue. What the code requires is that the ungrounded conductors be distinguishable from the grounded conductor and the grounding conductor, and, where more than one voltage system shares a building, that each system's phases be identified by a consistent means.
So the black-red-blue and brown-orange-yellow sets everyone uses are convention, not law, with three exceptions baked into the code itself. The grounded conductor is fixed at white or gray. The equipment ground is fixed at green or bare. And the high-leg of a 4-wire delta is fixed at orange. Everything else about phase color is industry habit that the AHJ may or may not enforce as a local amendment.
That does not make the convention optional in practice. Break from black-red-blue on a job where every other panel uses it and you have created the exact confusion the identification rules exist to prevent. Convention is not code, but ignoring a good convention is how the next electrician gets surprised.
The two common color sets: 208 and 480
Two color sets cover most of the work in the United States, one for each common voltage class, and keeping them separate is how you keep 120 V and 277 V from getting confused in the same building.
For 120/208 V systems, the phases are black, red, and blue, with a white neutral and a green or bare ground. For 277/480 V systems, the phases are brown, orange, and yellow, with a gray neutral and a green or bare ground. The orange in the 480 set is a phase color and has nothing to do with the high-leg orange in a delta system, which is a separate rule and a common source of mix-ups.
The reason to hold these two sets apart is safety, not neatness. A 277 V lighting conductor and a 120 V branch conductor can sit in the same gutter, and a worker who grabs a brown wire expecting 120 V is in for a bad day. Matching the color set to the system voltage means the color warns you which class you are working in before you ever touch the meter. Remember that only the white or gray neutral, the green or bare ground, and the orange high-leg are code. The phase colors in both sets are convention.
| System | Phases (convention) | Neutral | Ground |
|---|---|---|---|
| 120/208V and 120/240V | Black, red, blue | White | Green or bare |
| 277/480V | Brown, orange, yellow | Gray | Green or bare |
| 4-wire delta with high-leg | High-leg is orange (110.15) | White | Green or bare |
What is a high leg?
A high-leg, also called a wild-leg or stinger, is the one phase in a 4-wire delta system that reads a higher voltage to ground than the other two. On a 240 V delta with a center-tapped transformer winding, two of the phases give you 120 V to the neutral and run the 120 V loads, while the third phase sits at roughly 208 V to ground. That third phase is the high-leg.
The NEC at 110.15 requires that high-leg to be marked orange, or identified by other effective means, where the neutral is present in the panel or junction box. This is one of the few phase colors the code actually mandates. The reason is blunt: land a 120 V load on the high-leg and you put 208 V across equipment built for 120 V, and it lets the smoke out.
The NEC, in 408.3(E), requires the high leg to land on the B phase, the center position, in panelboards and switchboards, so the orange wire and the B busbar line up. Utility metering equipment historically used the C phase, and some older gear differs, so confirm which busbar is the high-leg with a meter rather than assuming it is B. The orange tells you the conductor is the high-leg. The meter tells you which busbar it actually landed on.
Where colors actually are required
Strip away the convention and a short list of identification rules are genuine code, enforceable, and worth knowing cold. The grounded conductor is white or gray. The equipment ground is green, green-with-yellow, or bare. The high-leg, where a neutral is present, is orange. Those three the NEC fixes by color.
Past that, the requirement is about consistency rather than a specific color. Where a premises has more than one nominal voltage system, the code requires each system's ungrounded conductors to be identified, by phase and by system, and the identification method to be documented or posted where the conductors originate. The branch-circuit rule and the feeder rule both say this, and they get their own sections next.
So the honest answer to what color the code requires is this: white or gray for the neutral, green or bare for the ground, orange for the high-leg, and a consistent identifiable scheme for the phases when more than one voltage is in the building. The specific phase colors are yours to choose, as long as you choose once, stick to it, and post what you chose.
Multiple voltage systems: the 210.5 and 215.12 rule
Once a building has more than one voltage system, say 120/208 V and 277/480 V, the NEC stops leaving phase identification to habit and requires it. Branch circuits fall under 210.5 and feeders under 215.12, and both say the same thing: where the premises is supplied by more than one nominal voltage system, each ungrounded conductor has to be identified by phase or line and by system, at every termination, connection, and splice point.
The means is flexible. The code permits separate color coding, marking tape, tagging, or other approved means. You do not have to use a particular color, but you do have to use a method, apply it consistently, and make it readable wherever the conductors are accessible.
The part crews skip is the posting. The identification method has to be documented and made available, or permanently posted, at each panelboard or distribution point. A legend taped inside the panel door that says black-red-blue is 208 V and brown-orange-yellow is 480 V satisfies that, and it is the first thing an inspector looks for on a multi-voltage job. No posted legend, no way to prove the scheme, and the identification rule has not been met no matter how clean the wire looks.
Re-identifying a conductor in the field
Re-identification is re-marking a conductor so it reads as something other than its insulation color, and the code allows it only in specific spots. The classic case is the white conductor used as an ungrounded conductor in a cable assembly, the switch loop being the everyday example. The NEC permits it, but the white has to be permanently re-identified, by paint, tape, or other effective marking, at each location where the conductor is visible and accessible, so nobody downstream reads it as a neutral.
The marking has to be durable and it has to be at every accessible point, not just the one end you happened to be standing at. A single wrap of black tape at the switch, with the other end left white in the panel, is the re-identification done halfway, and it is exactly how a white-as-hot kills someone who trusted the color at the far end.
You cannot re-identify in the other direction at small sizes. A green conductor cannot become a phase, and at 6 AWG and smaller a colored conductor cannot be re-marked white to serve as a neutral. Green and white-for-neutral are reserved at those sizes, and tape does not buy you out of it.
Large conductors: marking at the terminations
On conductors 4 AWG and larger the rules loosen, because manufacturers do not stock every size in every color and pulling 500 kcmil in five colors is not realistic. For these larger conductors the NEC lets you field-mark identification at the terminations rather than requiring the color to run the whole length.
A grounded conductor 4 AWG or larger can be identified by a distinctive white or gray marking, tape or paint that encircles the conductor, applied at each termination at the time of installation. An equipment grounding conductor 4 AWG or larger can be re-identified green at each accessible point the same way. And the phases on a large feeder get their color set with tape at the terminations and at any accessible junction.
This is why a panel full of big black feeders with colored tape at the lugs is correct and common. The tape at the terminations is the identification. What goes wrong here is consistency and completeness: the same phase taped the same color at both ends and at every box in between, with the neutral and ground marked at every termination, not just the ones that were easy to reach.
One scheme, the whole job, posted at the panel
Pick a color scheme and use it on the entire job. The value of identification is that it is predictable, and predictability dies the moment one floor wires 208 V as black-red-blue and another floor improvises. The next electrician, the inspector, and the troubleshooter at 2 a.m. all rely on the scheme being the same in every panel.
The posted legend is what makes that scheme official. On a multi-voltage job the code wants the identification method documented and available or permanently posted at each panelboard, and the practical form is a printed legend inside the panel door or on the directory: which colors are which system, and which busbar is the high-leg if there is one. The circuit directory itself is a separate requirement and a separate kind of identification, telling which breaker feeds what. Both belong in the panel.
A legend costs nothing and answers the question every future visit asks first. Skip it and you have left the next person to reverse-engineer your color choices with a meter, which is slower, and on the high-leg, dangerous.
Marking methods: tape, heat-shrink, and the half-lap
Colored electrical tape is the everyday tool for identification, and it works when it is applied like it is meant to last. Wrap a half-lap, each turn covering half the last, for a band wide enough to read, an inch or two, and stretch the tape slightly so it conforms and stays. A single loose wrap that unwinds in the heat of a gutter is identification that will not be there when it is needed.
Heat-shrink in the right color is more durable than tape and is worth it on terminations that get handled, in wet locations, or anywhere the tape would peel. Colored markers and printed wire markers cover the phase-and-system tagging the multi-voltage rule asks for, and pre-printed tags or sleeves read cleaner than a marker scrawled on a feeder.
Mark at the terminations and at every accessible box and junction, not just one end. The identification has to be readable wherever the conductor is exposed, because the person reading it could open any of those points. A conductor marked at the panel and left bare at the device is marked for the inspector and not for the electrician who actually has to work on it.
DC systems: solar, batteries, and the PV marking rule
DC has its own conventions and they do not match AC. In most DC work, red is the positive conductor and black is the negative, which trips up electricians who read black as a hot out of AC habit. In a grounded DC system the grounded conductor is white or gray, the same as on the AC side.
Photovoltaic systems add a layer that color alone does not cover. NEC Article 690 requires PV circuit conductors to be marked with photovoltaic identification at junction boxes, combiners, disconnects, and along the run, and that marking is a printed label, not just a color. The reason is that PV conductors can be energized by sunlight even with the system switched off, so a worker has to read this is a live PV source circuit off the label, not infer it from a wire color.
Battery and direct-DC distribution are showing up on more datacenter and site jobs, and the polarity marking matters there for the same reason it matters in a panel: reverse positive and negative and you damage equipment or worse. Confirm polarity with a meter before landing DC conductors. The color is the convention. The meter is the proof.
IEC colors and imported equipment
Equipment built to international wiring standards uses a different color set, and it lands on US jobs inside imported machinery and packaged equipment more often than people expect. Under the IEC scheme the phases are brown, black, and grey, the neutral is blue, and the ground is green-and-yellow.
The collisions are the dangerous part. IEC blue is a neutral; in the US, blue is a phase color in the 208 V set. IEC brown is a phase, and the US 480 set also uses brown for a phase, so that one happens to line up, but the blue does not. An electrician who reads an imported machine's blue conductor as a US phase, or its brown as a US neutral, has the identification exactly backwards.
The ground is the one point of agreement. Green-with-yellow is a grounding conductor in both systems, which is why it has become the closest thing to a universal color. When you tie imported gear into a US system, identify and re-mark the conductors to the US scheme at the interface, document it, and meter every conductor before you trust it. The factory color inside the machine tells you what the factory meant, not what your panel means.
Color is a guide, not a guarantee
Never trust color alone. This rule outranks every other line in this guide, because all the identification in the code is only as good as the last person who followed it. Colors get re-used. A previous crew lands a white as a hot and forgets to re-mark it. Someone pulls the wrong reel. An imported machine brings IEC colors into a US panel. The wire that is supposed to be dead reads 277 V because the identification lied.
So you verify. Before you touch a conductor as if it is safe, test it dead with a meter you just proved on a known live source, then check it again after. Treat every conductor as energized until your own meter says otherwise, regardless of what color it is or what the legend on the door claims.
Color speeds the work and tells you what the installer intended. It does not tell you what is on the wire right now. The electrician who confuses those two finds out the hard way that orange tape over a 480 V phase does not make it safe to grab. The meter is the only thing that does.
Control, signal, fire-alarm, and low-voltage wiring
Control and signal wiring carries its own color habits that differ from power wiring. In industrial control panels, red is commonly the AC control conductor, blue often marks DC control, and yellow flags a conductor that stays energized from a separate source even when the main disconnect is off. These follow industrial control standards more than the NEC power-wiring rules, and the panel's own legend governs, so read it before assuming anything.
Fire alarm and other life-safety low-voltage systems run on their own conventions, often red-jacketed cable for fire alarm to keep it visually separate from everything else. Those conventions come from the system manufacturer and the life-safety standards for the system, not from the power-wiring articles, and they vary by installer and by jurisdiction.
The lesson across all of it is that color convention is local to the system. The colors in a 480 V feeder, a PLC control panel, and a fire-alarm loop are three different vocabularies, and reading one with the rules of another is how a control conductor gets crossed. Identify which system you are in first, then read its colors, and meter anything you are about to treat as dead.
What the inspector checks
An inspector on a multi-voltage job looks for the posted identification scheme before they trace a single circuit. The legend inside the panel door, the one that says which colors are which system and which busbar is the high-leg, is the document that proves the 210.5 and 215.12 identification was actually done. No legend, and the cleanest wiring in the building still has an open identification item.
After the legend they check that it matches the wire. The high-leg is orange and landed where the legend says. The neutrals are white or gray and not doing double duty as a hot. The grounds are green or bare and not carrying a phase. Re-identified conductors, the white-as-hot in the switch loops, are marked at every accessible point, not just one end. Large feeders are taped consistently at the terminations.
The thing that fails inspection most often is not a wrong color. It is the missing legend on a multi-voltage job and the white conductor used as a hot without re-identification at both ends. Both are easy to fix before the inspector arrives and expensive to fix after the cover plates are on.
Large feeders and datacenter phase marking
On large feeders and in datacenters, phase identification is taped, not colored in the insulation, and the discipline is keeping A, B, and C consistent across the whole distribution. A datacenter runs parallel sets of large conductors, and a parallel run only shares current correctly when every conductor of the same phase is actually the same phase end to end. Tape A blue at one end and the wrong conductor blue at the other and you have set up a circulating-current and overload problem that a single wrong color tag started.
Phase rotation matters here too. Three-phase motors and many datacenter loads care about A-B-C sequence, so the phase marking has to carry the rotation, not just the fact that three phases are present. The marking is how the next person keeps the rotation right when they extend or repair the run.
Mark every parallel conductor, at every termination and pull point, the same color for the same phase, and verify the rotation with a phase-rotation meter at energization. On this scale the colored tape is the only practical identification, which puts all the weight on applying it consistently and checking it with an instrument before the load goes on.
What to document
The identification scheme is only useful if it is written down where the next person finds it. The panel legend is the front-line record, but the project record should also capture which scheme was used and where any re-identification or imported-color interface lives.
Capture the color set used for each voltage system, which busbar is the high-leg if there is one, every conductor that was re-identified and where, and any point where imported IEC-colored equipment ties into the US scheme. If the AHJ enforces a specific phase scheme as a local amendment, record that too, because it is the reason the colors are what they are.
| Conductor or item | Identification | Note to record |
|---|---|---|
| Grounded (neutral) | White or gray | Which system uses white vs gray |
| Equipment ground | Green, green-yellow, or bare | Re-id marking if 4 AWG or larger |
| Phases (ungrounded) | Color set per system | 208 black-red-blue, 480 brown-orange-yellow, or local scheme |
| High-leg | Orange (110.15) | Which busbar it landed on, verified by meter |
| Re-identified white-as-hot | Permanent marking both ends | Location of every accessible marking point |
| Imported / IEC equipment | Re-marked to US scheme | Where the interface is and how it was marked |
| Posted legend | At each panelboard | Confirms 210.5 and 215.12 met |
Common mistakes
- Assuming the NEC mandates phase colors when black-red-blue and brown-orange-yellow are mostly convention.
- Leaving the high-leg unmarked, or assuming it is on B without confirming the busbar with a meter.
- Using a white or gray conductor as a hot without re-identifying it at every accessible point.
- Mixing the 208 V and 480 V color sets so a 277 V conductor reads like a 120 V one.
- Running no posted identification legend on a job with more than one voltage system.
- Trusting the wire color instead of metering the conductor dead before working on it.
- Letting the scheme drift, so different panels on the same job use different phase colors.
- Reading imported IEC colors with US rules, taking the blue neutral for a phase.
Field checklist
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Standards and references
The NEC, NFPA 70, is the framework. The grounded conductor identification lives at 200.6, the equipment grounding conductor identification at 250.119, the high-leg marking at 110.15, and the requirement to identify ungrounded conductors by phase and system where more than one voltage system is present at 210.5 for branch circuits and 215.12 for feeders. Re-identification of white conductors used as ungrounded is handled in Article 200 as well.
The point the code makes by what it does not say is as important as the sections it does include. It fixes the neutral, the ground, and the high-leg, and leaves the phase colors to convention except where a local amendment or a specific application says otherwise. Article and section numbers move between code cycles, so confirm them against the edition the jurisdiction has actually adopted and any local amendments before you cite them on a submittal.
PV identification falls under Article 690, industrial control wiring follows the control standards and the panel's own legend, and imported equipment carries IEC colors that have to be reconciled to the US scheme at the interface. Cite the section that controls the point, treat the phase-color conventions as conventions, and verify every conductor with a meter regardless of what any of it says.
Terms and conventions
The same conductor goes by different names across a drawing set, a spec, and a manufacturer sheet, so the vocabulary is worth pinning down.
The grounded conductor and the neutral are the same conductor in most systems, white or gray. The grounding conductor, the equipment ground or EGC, is the green or bare one, and is not the same thing as the neutral even though both bond to earth at the service. Ungrounded conductors, phases, hots, and line conductors are all the same thing. The high-leg goes by wild-leg and stinger. Re-identification means re-marking a conductor to read as a different type where the code allows it.
- Grounded conductor / neutral
- The current-carrying return, identified white or gray (NEC 200.6)
- Equipment grounding conductor (EGC)
- The fault-current path, green, green-yellow, or bare (NEC 250.119)
- Ungrounded conductor / phase / hot
- A line conductor, phase colors by convention, not NEC-mandated
- High-leg / wild-leg
- The higher-to-ground phase of a 4-wire delta, marked orange (110.15)
- Re-identification
- Permanently re-marking a conductor to read as a different type where allowed
- IEC colors
- Brown, black, grey phases, blue neutral, green-yellow ground, the international set
FAQ
What color are the wires in a 480 volt system?
In a 277/480 V system the common convention is brown, orange, and yellow for the three phases, with a gray neutral and a green or bare ground. The phase colors are industry convention, not an NEC mandate, while the gray neutral and green ground are fixed by code. Confirm any local amendment with the AHJ.
Does the NEC require specific colors for hot wires?
For ungrounded hot conductors the NEC does not require specific colors. Black, red, blue and brown, orange, yellow are convention. The code does fix the grounded conductor white or gray, the equipment ground green or bare, and the high-leg orange, and it requires phases to be distinguishable and identified by system on multi-voltage jobs.
What is a high leg?
A high-leg, or wild-leg, is the phase of a 4-wire delta system that reads higher to ground than the others, roughly 208 V on a 240 V delta. NEC 110.15 requires it marked orange where a neutral is present. Land a 120 V load on it and you put 208 V across 120 V equipment.
What color is the neutral wire?
The neutral, the grounded conductor, is white or gray under NEC 200.6. At 6 AWG and smaller the color has to be in the insulation, not added with tape. At 4 AWG and larger you can mark it white or gray at the terminations. White and gray are both legal, often split between two systems.
Can a white wire be used as a hot wire?
A white conductor can be used as an ungrounded hot only where the code allows, such as a switch loop in a cable, and only if it is permanently re-identified at every accessible point. Mark it at both ends, not just the switch. At 6 AWG and smaller a colored wire cannot be re-marked white for a neutral.
What color is the ground wire?
The equipment grounding conductor is green, green with one or more yellow stripes, or bare, under NEC 250.119. No other conductor may use green. At 4 AWG and larger an insulated conductor can be re-identified green at every accessible point. The bare or green wire carries fault current only when something has failed.
Do I have to label the wire colors at the panel?
On a job with more than one voltage system, yes. NEC 210.5 and 215.12 require the phase-and-system identification method to be documented and available or permanently posted at each panelboard. A legend inside the panel door listing which colors are which system satisfies it, and it is the first thing an inspector checks.
What are the wire colors for a 120/208 volt system?
In a 120/208 V system the common convention is black, red, and blue for the three phases, with a white neutral and a green or bare ground. The phase colors are convention, not an NEC requirement; the white neutral and green ground are fixed by code. Hold this set separate from the 480 V set.
Are IEC wire colors the same as US colors?
No. The IEC set uses brown, black, and grey for phases, blue for neutral, and green-yellow for ground. The collision that bites is blue: a neutral under IEC, a phase in the US 208 V set. Only the green-yellow ground agrees. Re-mark imported equipment to the US scheme at the interface and meter it.
Can I trust wire color to tell me what is energized?
No. Color tells you what the installer intended, not what is on the wire now. Colors get re-used, neutrals get used as hots without re-marking, and imported gear brings IEC colors. Test every conductor dead with a meter you proved on a known source before you treat it as safe, whatever its color.
People also ask
Codes cited in this guide
This guide is written and reviewed against the published standards below. Always confirm the current adopted edition with the authority having jurisdiction.