UL1331 FEP Teflon Hook-Up Wire, 600 V / 150 °C

Overview

A UL1331 FEP wire is a single-conductor hook-up wire insulated with extruded FEP (fluorinated ethylene propylene) and rated 600 V and 150 °C to UL758. HKWIRE supplies it in tinned copper from AWG 30 to 4/0, with a uniform 0.50 mm insulation wall on the common sizes so it strips and cuts cleanly, in nine stock colors including transparent.

It is the practical middle step in the fluoropolymer family. FEP melts and extrudes like a thermoplastic, so the wall is uniform and the wire terminates without the fusing step that PTFE demands; in exchange, the temperature ceiling sits at 150 °C rather than the 200 °C to 260 °C range of PTFE styles. Where a run never leaves that window, specifying PTFE anyway is paying for headroom that will never be used.

The decision is rarely “which insulation is best” and almost always “which one is enough for this section of the machine.” If the temperature, the voltage and the routing are known, the choice becomes arithmetic rather than preference. For the full trade-off against silicone, FEP, PTFE and polyimide insulation — including the ≈6 kV/mm working stress that sets a real high-voltage rating — see our Kapton vs PTFE vs FEP vs silicone comparison, and the silicone wire harness page for the extruded end of the range.

Key Specifications

Construction and Materials

The insulation is FEP fluoropolymer, melt-extruded over the conductor. Because FEP flows during extrusion rather than being paste-extruded and sintered the way PTFE is, the finished wall is uniform around the conductor, which is what makes stripping and cutting predictable in production. That uniformity is the reason the style is specified for appliance and luminaire wiring, where termination speed matters as much as the electrical rating.

The standard conductor is tinned copper, stranded or solid, with silver- or nickel-plated copper available where the termination method or the temperature calls for it. Tinning keeps the strands solderable after storage and resists the surface oxidation that bare copper picks up in a humid factory. The construction carries a UL VW-1 and CUL FT1 vertical flame rating.

Typical Applications for UL1331 FEP Wire

This style is used for internal wiring where heat, not motion, is the dominant stress:

• Household appliances — internal leads near heating elements and motors
• Lighting fixtures and luminaires — wiring that sits in the thermal path of the lamp
• Industrial machinery — control and sensor wiring inside hot enclosures
• Electric heating products — heaters, ovens and thermal equipment leads
• Electronic thermal products and sensors — leads that must stay stable while the housing warms

Where the run is continuously flexed rather than heated — a drag chain, a moving axis, a robot wrist — a dedicated high-flex construction with the right stranding and jacket is the better starting point. Heat rating and flex life are different problems, and a wire chosen for one rarely excels at the other.

Size Range and Reel Lengths

The table below lists the full published range with stranding, wall, finished diameter, maximum conductor resistance at 20 °C and the standard reel length. Resistance values are the UL style maximums, so a compliant part will measure at or below the figure shown.

Custom Builds and Ordering

Cut lengths, non-stock colors and complete harness assemblies built with this wire are quoted per project. Send the drawing, the sample or the size and length list, and we will confirm what we can hold to tolerance before you commit. Where an assembly is built rather than a reel shipped, the electrical limits, sampling and records are agreed in writing before production release.

Packaging and Shipping

Standard reels are 610 m for the smaller sizes and 305 m from AWG 20 upward, dropping to 152.5 m and 76.25 m on AWG 8 and larger as the reel weight climbs. Reels are boxed, and boxed reels are palletized for container shipment. Cut-to-length orders are packed to the length list rather than to a reel count, so tell us the quantity of pieces as well as the total meterage.

Quality and Compliance

This wire is built to UL758 as a UL and CUL AWM style and passes the UL VW-1 and CUL FT1 vertical flame tests. HKWIRE is ISO 9001 certified and provides RoHS and REACH declarations per project. We do not claim certifications beyond those listed here, and where a project calls for a documented compliance mark we will tell you plainly whether this style carries it.

Related Cable Ranges

• Signal and data cables
• Custom wire harnesses
• Automotive cable and wire harness