Electrical Wire Color Codes Explained

Electrical wire color codes identify intended conductor roles: black/red/blue commonly marks US 120/208 V phases, while brown/orange/yellow commonly marks 277/480 V phases. Those phase combinations are conventions, not a universal NEC color assignment; Ohio Wire Buyers evaluates reusable surplus using the reel tag, insulation markings, footage and condition as well as color.

0100 FTElectrical wire color codes: the common US chart

The chart below describes common three-phase AC practices. It is not a wiring instruction or proof that an installed conductor belongs to the system shown.

White on the lower-voltage system and gray on the higher-voltage system helps distinguish neutrals, but that particular allocation is not universal. Use the project's electrical specifications and posted identification scheme rather than assuming every facility follows this chart.

For surplus THHN/THWN-2 building wire, record the factory color as part of the product description. Do not label a loose blue reel as “208-volt wire” merely because blue appears in that convention.

0200 FTWhich colors does the NEC actually require?

The National Electrical Code has identification requirements for grounded conductors and equipment grounding conductors. NFPA's grounding and bonding reference explains white, gray and specified white or gray stripe identification under Section 200.6, and green or green with yellow stripes for covered or insulated equipment grounding conductors under Section 250.119. Equipment grounding conductors can also be bare.

Grounded and grounding are different terms. A neutral is a circuit conductor; an equipment grounding conductor provides a ground-fault current path and connects normally non-current-carrying metal parts. Treating them as interchangeable because both relate to grounding is a serious mistake.

The statement “the NEC only specifies neutral and ground colors” also needs a qualification. Section 110.15 addresses high-leg marking on certain delta-connected systems, requiring orange or other effective identification. Thus, orange can signify a high leg rather than the customary phase B of a 277/480 V system.

Black/red/blue and brown/orange/yellow are widely recognized phase conventions. They do not replace the applicable code, project requirements or verification of the actual installation.

0300 FTCan you identify voltage or condition from color alone?

No. Factory color does not tell you the conductor metal, insulation type, voltage rating, remaining footage or suitability for another installation. Black XHHW-2 feeder wire and black THHN can look similar at a glance while having different product identities.

Start with the printed cable legend. Match it to the reel tag, then inspect the visible jacket and accessible ends for damage. Field-applied tape and sleeves should be recorded separately from factory insulation color; do not describe black wire with white tape as factory-white product.

For installed or decommissioned material, color is never an absence-of-voltage test. OSHA's electrical work-practice standard requires qualified-person testing to verify a de-energized condition, including possible backfeed or induced voltage. Have qualified personnel isolate and remove cable under the applicable procedures before preparing it for sale.

0400 FTWhat do NM-B outer jacket colors tell you?

An NM-B outer jacket is a separate identification layer from the insulation on its individual conductors. Jacket colors help distinguish product constructions, but manufacturer schemes and older inventory can differ. They do not replace the printed gauge and conductor count.

The following combinations come from Cerrowire's current CerroMax NM-B specifications, not a universal NEC jacket-color mandate.

The slash count describes insulated circuit conductors, not the equipment grounding conductor supplied with these constructions. When listing surplus NM-B coils, include the complete printed designation and grounding information. A yellow coil and a purple coil should not be combined into one inventory line just because both contain the same gauge copper.

0500 FTWhy do multiconductor cables use stripes or numbers?

A control cable may contain more conductors than a simple power-circuit color chart can distinguish. Southwire's conductor-identification reference describes base colors with tracers, single-color insulation with printed color designations, and sequentially numbered conductors.

These methods identify individual conductors within an assembly. They are not automatically a declaration that every internal color follows the common building-wire phase chart. The specified identification method matters when matching replacement cable to a drawing or purchasing specification.

For multiconductor control cable, photograph both the base insulation colors and any tracer stripes or numbers. For power tray cable, preserve the outer jacket legend and manufacturer part number as well. An outside photograph of a black reel cannot establish its internal conductor identification.

0600 FTHow does color affect surplus resale?

Color affects whether a reusable reel fits another buyer's specified installation. Familiar phase, neutral and grounding colors can simplify that match, but color alone does not establish a premium or how quickly a lot will sell. An unusual color is not automatically scrap.

Preserve continuous lengths and original identification. Do not cut a mixed-color lot into short pieces merely to create uniform bundles, and do not remove tags while rearranging reels. List each color separately even when the manufacturer, size and insulation type match.

Distinguish genuine discoloration or jacket damage from a harmless difference in the manufacturer's color shade. Send clear photos rather than repainting, retaping or otherwise changing the material to make it look uniform. Our reuse-versus-scrap guide explains why a documented usable product is evaluated differently from recoverable metal.

0700 FTWhat should you send for an offer on colored wire?

Use a separate inventory line for each reel, coil or continuous cut length. Include manufacturer, printed type, conductor size, copper or aluminum, factory color, footage or estimate, and whether it is unused or previously installed. Mark unknown information as unknown rather than filling gaps from the color chart.

Photograph the whole lot, each reel tag, readable jacket print and accessible cut ends. Add close-ups of tracer stripes, conductor numbers and field-applied identification. For boxed NM-B, show the package label and jacket designation; for partial reels, distinguish original tag footage from your estimate of what remains.

Our wire photography guide and reel-tag guide help organize those details. Ohio Wire Buyers verifies the seller and proof of ownership, reviews the material, and replies with questions or a written offer before pickup. Payment method and timing are confirmed in writing before pickup; we arrange pickup anywhere in Ohio and check the count against the written terms.

Ohio Wire Buyers buys reusable surplus as product for resale and reuse, not scrap metal by the pound. Send your color-by-color inventory through the offer form, or call 951-403-5738. For more help identifying the lot before submitting it, use our wire selling guides.