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UL 1659 PTFE wire 250C 600V for high temperature internal wiring

UL AWM Style 1659 is a single conductor with extruded PTFE/TFE insulation, rated 250°C and 600 Vac. The Style covers 26 AWG to 4/0 AWG in solid or stranded round construction, with insulation thickness set in three groups: 20 mils minimum average for 26–10 AWG, 30 mils for 8–2 AWG and 45 mils for 1–4/0 AWG. A mica tape wrap and a treated glass braid are available as optional constructions, and Oil Resistant 80°C and Gasoline Resistant are optional ratings available only by confirmed construction. The stated use is internal wiring. Conductor material, plating, marking and required documents are confirmed by quotation.

UL AWM Style 1659 is a single conductor with extruded insulation, defined under UL Subject 758, Section 1. The insulation material is PTFE/TFE, and the Style is rated 250°C and 600 Vac across a conductor range of 26 AWG to 4/0 AWG in solid or stranded round construction. The stated use is internal wiring.

Two features distinguish this Style within the fluoropolymer range. The insulation thickness steps across three AWG groups rather than remaining constant, so finished dimensions change noticeably at the group boundaries. And the Style file lists four optional elements — a mica tape wrap, a treated glass braid, an Oil Resistant 80°C rating and a Gasoline Resistant rating — none of which is a default characteristic. Each has to be specified and confirmed for the ordered construction.

UL 1659 PTFE wire cross section showing conductor and extruded PTFE/TFE insulation, 250°C, 600 Vac

UL 1659 Ratings and Construction

UL AWM Style1659
ConstructionSingle conductor with extruded insulation
UL Subject / Section758, Section 1
Temperature rating250°C
Voltage rating600 Vac
Conductor range26 AWG – 4/0 AWG, solid or stranded round
Insulation materialPTFE / TFE
Optional coveringMica tape wrap
Optional braidTreated glass braid
Optional ratingsOil Resistant 80°C; Gasoline Resistant
Flame ratingHorizontal Flame per the UL Style file; VW-1 vertical flame testing available by confirmed construction and agreed order requirement
MarkingGeneral, per UL Subject 758 marking requirements
Use per UL Style fileInternal wiring

Insulation Thickness by AWG Range

AWG rangeMinimum averageMinimum at any point
26–10 AWG20 mils18 mils
8–2 AWG30 mils27 mils
1–4/0 AWG45 mils40 mils

These are the only fixed dimensional values in the Style. Where an order spans a group boundary — 10 AWG and 8 AWG, for example — expect a step change in finished outside diameter and check it against the routing and termination hardware in the assembly.

UL 1659 PTFE wire optional constructions showing mica tape wrap and treated glass braid covering

Available UL 1659 Order Options

The UL Style range is 26 AWG through 4/0 AWG in solid or stranded round construction. Both conductor forms are within scope across the full range.

The Style file does not define a conductor material, plating, strand count or conductor resistance. Those are established for the specific ordered construction, together with insulation colour, finished outside diameter, reel length, wire marking and packaging format. The optional elements — mica tape wrap, treated glass braid, Oil Resistant 80°C rating and Gasoline Resistant rating — must each be specified separately at enquiry; they are not applied by default and are available only where supported by the applicable ordered construction.

Where a requested combination of AWG, conductor construction, optional covering and optional rating has not previously been produced, confirm feasibility during enquiry rather than assuming availability from the Style scope alone.

Internal Wiring Applications

The UL Style 1659 file states the use as internal wiring. That is the boundary within which this product is supplied and should be specified.

Within that scope, UL 1659 is typically considered for internal wiring in equipment where the internal operating temperature at the wire location is a design factor, subject to the actual equipment design and order confirmation. Whether a specific construction is suitable for a given installation depends on the equipment, the internal routing arrangement, the ordered construction and the applicable equipment-level evaluation — not on the Style rating alone.

This Style is not supplied or positioned for building wiring, field wiring, general power cable, direct heating-element leads, direct flame exposure, open furnace routing or outdoor wiring. Chemical exposure conditions require the applicable optional rating to be confirmed for the ordered construction rather than assumed from the insulation material.

UL 1659 PTFE wire routed as protected internal wiring inside an equipment enclosure, 250°C, 600 Vac

Optional Oil and Gasoline Resistance

The Style file lists Oil Resistant 80°C and Gasoline Resistant as optional ratings. They are not characteristics of all UL 1659 wire, and they are separate from the optional mica tape wrap and treated glass braid constructions — specifying one does not carry the other.

Where either optional rating is required, the ordered construction, the applicable optional rating, the actual product marking and any required test or supporting documentation must all be confirmed during quotation. Do not assume the rating applies to a construction unless it has been confirmed for that specific order.

UL 1659 PTFE wire colour options, 26 AWG to 4/0 AWG, 250°C 600 Vac

UL Marking and Order Documentation

The ordered construction, the applicable certified scope, the actual UL marking applied and the supporting documents must all be confirmed before production. Only products bearing the applicable UL Mark should be represented as covered products.

Where UL, RoHS, REACH, oil-resistance, gasoline-resistance or other documents are required, specify them during enquiry so availability can be confirmed for the ordered construction. Minimum order quantity, sample availability, reel length, packaging, delivery schedule and marking are confirmed in the quotation rather than fixed in advance.

Related Fluoropolymer Wire Products

For the full range of UL 1659 constructions, see the UL 1659 PTFE wire category. Two other fluoropolymer Styles are available: UL 1332 (200°C / 300 Vac, extruded FEP, 30–10 AWG) and UL 10362 (250°C / 600 Vac, extruded PFA, 30 AWG–4/0 AWG). Selection between them should follow the insulation material, ratings and conductor range required by the equipment design.

The wider ranges are available under Fluoropolymer Wire and AWM Wire.

Request a UL 1659 Wire Quote

Send the following with your enquiry so the construction can be confirmed against the applicable certified scope:

  • AWG size
  • Solid or stranded round requirement
  • Requested conductor material and plating
  • Detailed stranding requirement
  • Required finished outside diameter
  • Colour
  • Mica tape wrap requirement
  • Treated glass braid requirement
  • Oil-resistant or gasoline-resistant rating requirement
  • Quantity
  • Reel or cut length
  • Packaging format
  • Equipment type
  • Internal routing condition
  • Actual temperature requirement at the wire location
  • Voltage requirement
  • Required wire marking
  • Required order documents
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