SPT-3 är en kabelbeteckning enligt NEC / UL (USA): S = Service cord; P = Parallel (zip) construction; T = Thermoplastic (PVC); -3 = Insulation thickness class 3 (UNVERIFIED); SPT-3 = Parallel thermoplastic lamp cord, insulation class 3. 300 V, 60 to 105 C (UNVERIFIED). UL 62; NEC Table 400.4.