THHN/THWN-2 is one of the most widely used building wires in North America. The letters describe three constructions that share one jacket: THHN (heat-resistant thermoplastic, dry locations), THWN (heat- and moisture-resistant) and THWN-2 (the modern dual-rated version for wet and dry locations up to 90°C).

Construction is straightforward: bare annealed copper conductor, PVC insulation and a tough nylon jacket, rated 600V and listed to UL 83. Sizes run from 14 AWG solid up to 1000 kcmil stranded, in standard and custom colours.

• Check the temperature rating you actually need (75°C vs 90°C changes ampacity).
• Confirm wet-location rating — always order THWN-2 dual-rated.
• Agree on spool lengths (500 ft / 1000 ft) and reel packing before ordering.
• Ask for the UL file number and latest test report with your shipment.

Our partner mill produces THHN/THWN-2 on high-speed lines with full UL certification. Send us your size list and destination port for a quotation within 24 hours.