UL 1659 PTFE Wire

UL 1659 is a PTFE (polytetrafluoroethylene) insulated wire rated 250°C and 600V AC under UL AWM Style 1659, produced under UL Follow-Up Service File No. E333030. PTFE is the original fluoropolymer and the most thermally capable — its continuous service temperature of 250°C is the highest of any standard AWM wire insulation material, and its chemical resistance profile covers virtually every industrial acid, alkali, solvent, and fuel, making UL 1659 the specification for internal wiring in chemical processing equipment, laboratory instruments, semiconductor manufacturing equipment, and any application combining elevated temperature with aggressive chemical exposure.

PTFE insulation is applied by paste-ram extrusion rather than melt extrusion — a process that produces insulation with a slightly matte surface finish compared to FEP or PFA, but with superior dielectric strength and chemical resistance. The low dielectric constant of PTFE (εr = 2.1) also makes UL 1659 the preferred specification for high-frequency signal wiring in instrumentation and RF applications. For applications requiring maximum flexibility at rated temperature, see UL 10362 PFA wire. Available in 26 AWG to 4/0 AWG, RoHS and REACH compliant.