High Temperature Mica Fiber Braided Furnace Cable — UL 5107 / 5128 / 5334 / 5476 Selection Guide
Mica fiber braided furnace cable is the only UL AWM wire construction rated for continuous internal wiring service at 450°C — the temperature range where all organic polymer insulations have permanently failed and inorganic mineral insulation is the only viable specification. Four UL AWM styles cover this construction family under UL Subject 758: Style 5107, 5128, 5334, and 5476. Selecting the correct style requires matching three parameters simultaneously: temperature rating, voltage rating, and AWG range.
This page provides a complete selection guide for all four UL AWM mica wire styles — helping procurement engineers identify the correct certified construction for each furnace internal wiring application without over-specifying or under-specifying the insulation system.
UL AWM Mica Style Selection Guide
| UL Style | Temp Rating | Voltage | AWG Range | Mica Wall (26–12 AWG) | Best For |
|---|---|---|---|---|---|
| UL 5107 | 200°C or 450°C | 600V | 26 AWG–550 kcmil | 25 mils min avg + 7 mils glass braid | Power circuits, heating element leads, widest AWG range |
| UL 5128 | 450°C | 300V | 24 AWG–4 AWG | 15 mils min avg + 7 mils glass braid | Instrumentation, thermocouple leads, compact routing |
| UL 5334 | 450°C | 300V | 24 AWG–4 AWG | 17 mils composite mica + 5 mils glass braid | Oven wiring — UL use classification explicitly references ovens |
| UL 5476 | 450°C | 600V | 30 AWG–4/0 AWG | 17 mils min avg + 7 mils glass braid | Latest 2025 revision — new facility specifications |
How to Select the Correct UL Mica Style
Step 1 — Determine voltage requirement
If your furnace heating element circuit operates at mains voltage (120V, 220V, 240V, or 480V AC) and you need 600V insulation rating — specify UL 5107 or UL 5476. If your application is instrumentation, thermocouple signal leads, or control circuits where 300V insulation is adequate — specify UL 5128 or UL 5334. The 300V styles have thinner insulation walls, producing more compact wire diameters that route more easily through ceramic standoff insulators and narrow wiring channels in furnace structures.
Step 2 — Match AWG range to your conductor size
UL 5107 covers the widest AWG range — 26 AWG through 550 kcmil — making it the default choice for heavy-gauge heating element leads and power distribution circuits. UL 5476 covers 30 AWG through 4/0 AWG including fine gauge ranges not available in 5107. UL 5128 and 5334 are limited to 24 AWG through 4 AWG — the instrumentation and light power circuit range. If your AWG falls outside the certified range of a specific style, you must select a style whose certified range covers your AWG.
Step 3 — Check the use classification
UL 5334 is the only style in this family whose UL use classification explicitly references “ovens or similar high-temperature equipment” — making it the most straightforward compliance documentation choice for commercial oven internal wiring applications. UL 5107, 5128, and 5476 are classified for “internal wiring of high-temperature equipment” — a broader classification that covers furnaces, kilns, and ovens, but without the explicit oven reference of Style 5334.
Step 4 — Consider revision date for new projects
UL 5476 was last revised in May 2025 — the most recent revision in the mica wire family. For new facility construction projects where procurement specifications reference “current UL revision,” Style 5476 satisfies this requirement. Styles 5107, 5128, and 5334 have pre-2020 revision dates — adequate for existing installations and maintenance replacement, but Style 5476 is the preferred specification for new equipment designs requiring the most current UL certification revision.
Full Technical Specifications
| Parameter | Specification |
|---|---|
| Temperature Rating | 200°C or 450°C (style dependent) |
| Voltage Rating | 300V AC (5128/5334) or 600V AC (5107/5476) |
| Conductor | Solid or stranded copper (nickel-plated option available) |
| AWG Range | 30 AWG – 550 kcmil (style dependent) |
| Insulation | Non-extruded mica tape, multiple layers |
| Outer Covering | Treated fiberglass braid — silicone varnish or PTFE finish |
| Optional Shield | Stainless steel 304 braid (5128/5334/5476) |
| Flame Rating | Horizontal flame |
| Installation Type | Fixed static — not suitable for repeated flexing |
| UL Recognition | UL Recognized Component — file on record |
| MOQ | Cut-to-length from 1 meter / 50m standard coil |
Application Categories
Industrial Furnace and Kiln Heating Element Wiring
The primary application — internal wiring inside industrial furnaces operating at 400–450°C connecting resistance heating elements to terminal blocks and routing temperature sensor leads through the furnace hot zone. Specify UL 5107 for 600V heating element power leads; specify UL 5128 for thermocouple and instrumentation signal leads in the same furnace.
Commercial Oven Internal Wiring
For commercial baking ovens, industrial dryers, and powder coating cure ovens where wire surface temperatures in the heating zone reach 200–300°C, UL 5334 provides the explicit UL oven wiring use classification — the most direct compliance documentation path for oven equipment UL certification.
Metal Smelting and Foundry Equipment
Wiring inside induction melting furnaces, arc furnaces, and resistance melting equipment where the wiring zone consistently exceeds 400°C and radiant heat from molten metal creates extreme thermal conditions. UL 5107 at the 450°C grade with nickel-plated copper conductor is the standard specification for these applications.
New Facility Construction
For new industrial facility projects where procurement specifications reference current UL revision standards, UL 5476 (revised May 2025) is the recommended specification — the most recently revised mica wire style in the UL AWM family.
Related UL Styles for Comparison
Mica furnace cable buyers commonly cross-reference: UL 5335 (450°C / 600V mica glass braid, heavier insulation wall for high-current power circuits in electric arc furnaces), UL 5359 (200–450°C / 600V mica tape with multi-conductor assembly option), UL 5360 (200–450°C / 300V mica tape, ultra-thin 12-mil wall for precision equipment), and UL 3135 (200°C / 600V silicone rubber, for applications where wire surface temperature does not exceed 200°C).
Request a Quote
Submit your UL Style (5107 / 5128 / 5334 / 5476), temperature grade, voltage, AWG, optional stainless steel braid, length, and annual volume estimate below. Our team responds within 24 business hours. Cut-to-length orders from 1 meter for maintenance replacement.
