UL 1592 FEP High Temp Wire 26 AWG — 200°C at 300 Vac, the Lower Bound of the Tinned Copper Window
UL 1592 in 26 AWG is a single-conductor wire with extruded FEP insulation, rated 200°C maximum at 300 Vac with a horizontal flame rating, recognised for internal wiring. The insulation is 16 mils minimum average thickness, 13 mils minimum at any point, uniform across the style’s 32 AWG to 16 AWG range. At 26 AWG the conductor sits exactly on the lower boundary of the range in which this style permits tinned copper — which makes it available, but subject to a strand diameter condition that materially constrains how the conductor can be built. CableApex supplies UL 1592 26 AWG as a UL Recognized Component — file on record.
The 15-mil Strand Floor and What It Rules Out
UL 1592 permits tinned copper conductor in sizes 26 AWG through 16 AWG, with tinned copper strands of a minimum 15 mils diameter. The size condition and the strand condition are separate requirements and both must be satisfied. At 26 AWG the first is met exactly; the second is where specifications commonly come unstuck.
A 15 mils strand is a relatively coarse element. Stranded conductors are normally described by a strand count and strand gauge that together produce the required total cross-section, and at a fixed total area there is an inverse relationship between the two — more strands means each is finer. A 26 AWG conductor has a modest total area to divide, so meeting a 15 mils floor on every strand limits the construction to a small number of relatively heavy strands. High-flex constructions built from many very fine strands, which are common in fine-gauge wire precisely because they improve flexibility and fatigue life, cannot satisfy that floor at this gauge in tinned copper. In practice, tinned copper at 26 AWG under UL 1592 means a coarse-strand or near-solid construction rather than a flexible one.
Conductor Construction Options at 26 AWG
| Construction | Strand character | Tinned copper under UL 1592 | Flexibility |
|---|---|---|---|
| Solid | Single element | Within the 26–16 AWG window | Low |
| Coarse stranded | Few strands, each 15 mils or heavier | Meets the strand floor | Moderate |
| Fine stranded / high flex | Many strands below 15 mils | Does not meet the strand floor | High |
Where a design needs both tinned copper and a genuinely flexible fine-strand construction at 26 AWG, UL 1591 recognises tin plated conductor across its full 32 to 16 AWG range without a strand diameter condition, at a 150°C rating. The choice comes down to whether the 200°C class or the conductor flexibility is the harder requirement.
UL 1592 26 AWG Specifications
| Item | Specification |
|---|---|
| UL Style | 1592 — single conductor with extruded insulation |
| Temperature Rating | 200°C maximum |
| Voltage Rating | 300 Vac |
| Conductor | 26 AWG, solid or stranded (style range 32–16 AWG) |
| Tinned Copper | Permitted in 26–16 AWG; tinned copper strands 15 mils minimum diameter |
| Insulation | Extruded FEP, 16 mils minimum average thickness, 13 mils minimum at any point |
| Flame Rating | Horizontal flame; VW-1 vertical flame test available |
| UL Recognition | UL Recognized Component — file on record |
| Marking | Per UL Subject 758 marking requirements |
| Permitted Use | Internal wiring |
| RoHS / REACH | Documentation available on request |
Specifying the Conductor Correctly
Because the strand condition applies to the individual strand rather than to the finished conductor, it cannot be verified from an AWG figure alone. When ordering tinned copper at 26 AWG under this style, state the intended strand count and strand gauge along with the total conductor size, so the construction can be checked against the 15 mils floor before manufacture rather than after. Where flexibility requirements have driven a fine-strand specification elsewhere in the same harness, it is worth confirming which leads actually need tinned copper — often the requirement traces back to a soldering process assumption that other conductor treatments also satisfy.
Applications
Within its permitted use — internal wiring — UL 1592 26 AWG suits fine sensor and signal leads, thermocouple extension wiring and low-current control conductors routed through zones reaching 200°C at 300 Vac or below. The style’s permitted use is stated as internal wiring without restriction to appliances, so it covers a wider range of equipment types than several neighbouring FEP styles. Solid and coarse-stranded constructions suit fixed routed leads; where repeated flexing is expected, confirm the conductor construction against the application before specifying. For applications outside internal wiring, confirm application suitability before specifying.
Key Features
- 26 AWG sits at the lower bound of the tinned copper window
- Tinned copper strands must be 15 mils minimum diameter
- 200°C maximum at 300 Vac with a 16 mils uniform FEP wall
- Permitted use stated as internal wiring, not restricted to appliances
- Horizontal flame; VW-1 vertical flame test available
- UL Recognized Component — file on record
Request a Quote
CableApex supplies UL 1592 26 AWG from 100 m per color and responds to B2B inquiries within 12 hours. Specify conductor construction, and for tinned copper the strand count and strand gauge, along with colors, through the form below so the construction can be confirmed against the style’s strand condition.
Related pages: UL 1592 24 AWG · UL 1591 FEP Wire (150°C / 300 Vac, plated conductors) · UL 1592 FEP Wire category
