... larger: black Standard: ASTM B3, NTC 359. :Soft copper wire.ASTM B8, NTC 307. :Concentric Lay Stranded copper conductors ... Combination Unilay Stranded Copper conductors for subsequent insulationUL 1581, NTC-3203.: Reference Standard for Electrical Wires, Cables and Flexible ... Cords.UL 83, NTC-1332. :Thermoplastic insulated Wires and Cables. Application: fixed ...