The roster
Listed alphabetically. The section also covers flexible metal conduit, so a company on this sheet may make conduit, wire, or both; the roster does not say which. NEMA’s profile and the company’s own product pages do.
| No. | Company | Also listed under | Where to check |
|---|---|---|---|
| 01 | Anamet Electrical, Inc. | NEMA profile anacondasealtite.com | |
| 02 | Atkore | NEMA profile atkore.com | |
| 03 | Cerrowire | NEMA profile cerrowire.com | |
| 04 | Colonial Wire & Cable Co., Inc. | NEMA profile colonialwire.com | |
| 05 | Copperweld Bimetallics, LLC | NEMA profile copperweld.com | |
| 06 | Electri-Flex Company | NEMA profile electriflex.com | |
| 07 | Encore Wire Corporation | NEMA profile encorewire.com | |
| 08 | Freeport-McMoRan | NEMA profile fcx.com | |
| 09 | Marmon Defense, LLC | NEMA profile marmon-ad.com | |
| 10 | Nexans | NEMA profile nexans.ca | |
| 11 | The Okonite Company | NEMA profile okonite.com | |
| 12 | Prysmian Group | NEMA profile prysmiangroup.com | |
| 13 | Service Wire Company | NEMA profile servicewire.com | |
| 14 | Southwire Company, LLC | NEMA profile southwire.com | |
| 15 | Xignux Corporativo | NEMA profile xignux.com |
Read this before using the list
Building wire is made in very large volumes by a small number of mills, and it is sold almost entirely through electrical distributors. Finding a maker is rarely the difficulty. Confirming that a given reel carries the listing the installation requires is the part worth time.
Why the listing matters more than the maker
In the United States a building is wired under the National Electrical Code, NFPA 70, as adopted by the state or city. The code does not approve brands. It requires conductors and cables of a named type, and inspectors accept a product as being of that type when a recognized testing laboratory has listed it. So the question for a buyer is less “who made this” than “is this reel listed as the type on the drawing”.
The type letters, and the standards behind them
A type designation is a compressed description. T is thermoplastic insulation, X is cross-linked; H is a
75 °C rating and HH is 90 °C; W is suitable for wet locations; N is a nylon jacket.
THHN is therefore thermoplastic, 90 °C, nylon-jacketed.
| Product | Common types | UL standard |
|---|---|---|
| Thermoplastic-insulated wire | THHN, THWN, THWN-2, TW | UL 83 |
| Thermoset-insulated wire | XHHW, XHHW-2, RHH, RHW | UL 44 |
| Nonmetallic-sheathed cable | NM-B, UF-B | UL 719, UL 493 |
| Metal-clad cable | MC | UL 1569 |
| Armored cable | AC | UL 4 |
| Service-entrance cable | SE, USE | UL 854 |
Standards are revised. Cite the edition your project is built to, or ask the maker which edition its listing was evaluated against.
Checking a building wire maker
- Read the print legend. Building wire is surface-marked along its length with the maker or its listing file, the type, size, voltage and temperature rating. A reel whose legend does not match its tag is the first thing to stop on.
- Look the listing up at the laboratory. UL, CSA and Intertek each run a public directory of what they have listed. Search by the company name or file number on the legend, and confirm the type is in the listing, not merely that the company has one.
- For aluminum, confirm the alloy. The code calls for an AA-8000 series alloy for aluminum building wire. The legend and the certificate of compliance should both say so.
- Ask where it was made if the job has domestic-content terms. Public works and federally assisted projects often do, and the answer has to be in writing for the reel, not for the brand.
More on verifying each of these at its source is in Qualifying a wire manufacturer.