xhhw er en kabelbetegnelse efter NEC / UL (USA): X = Thermoset (cross-linked polyethylene) insulation; HH = High heat resistant, 90 C; W = Approved for wet locations; XHHW = Thermoset (XLPE) high heat-resistant building wire, wet locations at 75 C. 600 V, 90 C dry, 75 C wet. UL 44; NEC Article 310.