THWN является маркой кабеля по системе NEC / UL (USA): T = Thermoplastic (PVC) insulation; H = Heat resistant, 75 C (one H); W = Approved for wet locations; N = Nylon outer covering; THWN = Thermoplastic heat- and water-resistant nylon-coated building wire, 75 C. 600 V, 75 C wet and dry. UL 83; NEC Article 310.