UL 3321 XLPE Wire

UL 3321 is a cross-linked polyethylene (XLPE) insulated wire rated 150°C and 600V AC under UL AWM Style 3321, produced under UL Follow-Up Service File No. E333030. UL 3321 is the highest-temperature grade in the standard XLPE AWM wire range — rated 25°C above UL 3266 (125°C) and 60°C above UL 3271 (90°C). The higher cross-link density of UL 3321’s XLPE compound provides additional thermal stability for applications where the combination of high ambient temperature, high current density, and restricted ventilation pushes conductor surface temperatures beyond the limits of lower-grade XLPE wire.

UL 3321 is the specification for large-conductor internal power connections in electrical rooms with elevated ambient temperatures — generator output to automatic transfer switch (ATS) connections, ATS to UPS input busbars, and UPS output to main distribution board feeds in data centre and critical facility electrical rooms where the equipment’s own heat load combined with outdoor summer ambient creates enclosure temperatures that exceed UL 3266’s 125°C margin. For mid-range XLPE motor lead applications, see UL 3266 (125°C). Available in 30 AWG to 4/0 AWG, RoHS and REACH compliant.