UL 3666 XLPE Wire

UL 3666 is a cross-linked polyethylene (XLPE) insulated wire rated 105°C and 600V AC under UL AWM Style 3666, produced under UL Follow-Up Service File No. E333030. UL 3666 is the entry-level XLPE grade in the CableApex XLPE range — rated at the same 105°C temperature as UL 1015 PVC wire but with cross-linked polyethylene insulation that does not soften or deform at rated temperature, providing better dimensional stability and thermal endurance than PVC in applications where the wire surface temperature approaches the 105°C continuous limit.

The cross-linking process creates permanent chemical bonds between polyethylene chains, converting the thermoplastic PE into a thermosetting material that maintains its physical form at its rated temperature — unlike PVC, which softens progressively above 90°C and may deform under mechanical pressure at the 105°C rating. This makes UL 3666 the preferred upgrade from UL 1015 PVC for motor leads, control panel internal wiring, and equipment wiring in high-ambient-temperature environments where PVC insulation deformation has been a reliability concern. For higher-temperature XLPE applications, see UL 3266 (125°C) and UL 3321 (150°C). Available in 30 AWG to 4/0 AWG, RoHS and REACH compliant.