(18) Applications For direct burial, for use in dwellings not exceeding 3 floors above grade, as underground feeder to outdoor lighting or apparatus, or as general branch circuit wiring. Recognized for use as exposed or concealed wiring in damp, moist, wet, dry, and corrosive locations. For use as new wiring or as replacement wiring.
Conductor is bare annealed copper per ASTM B-3 or stranded conductors, per ASTM B-8.
Insulation is color coded PVC (polyvinyl chloride) with a nylon jacket.
Type THHN inners, rated 90 ºC.
Ampacity is limited to that for 60 ºC conductors per NEC® Articles 336 and 339.