An image showing a MIL-W-25038 wire with some coating removed to show the wire underneath.

Key Features

  • Firezone wires for aircraft engine applications are designed to operate continuously at 260°C
  • Firezone applications are designed to operate for minimum of 15 minutes at up to 2000°F (1093°C), including in a direct flame
  • Firezone qualification must pass BSS 7324 and M25038 Shake and Bake Test


Shake and Bake Test Description:

  • Wire must withstand a flame temperature of 2,000° ± 50°F for 15 minutes
  • After the flame has been stabilized, the wire is vibrated 30 times per second, with the rack having a maximum total excursion (overall movement) of approximately .06 inches (1.52mm)
  • After 15 minutes, the lowest insulation resistance is measured
  • No insulation can flake or fall off during the flame exposure
Firezone Requirements v. Results
  Requirements Results
MIL-W-25038 50Ω 10kΩ

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Product Construction

MIL-W-25038/1 Construction Details
Jacket PTFE-coated fiberglass braid and finisher
Insulation Composite inorganic dielectric
Conductor 27% nickel-coated copper
MIL-W-25038/3 Construction Details
Jacket Fused high-performance PTFE tape (also available with Seamless Wrap PTFE tape)
Thermazone IIIK

Outer: PTFE/polyimide tape fluid barrier

Innter: Inorganic dielectric

Thermazone IIIG

Outer: PTFE-coated fiberglass fluid barrier

Inner: Inorganic dielectric


12-18 AWG: 27% nickel-coated copper

20-22 AWG: 27% nickel-coated high-strength copper alloy

Mechanical/Environmental Performance

Voltage Rating 600V
Temperature Rating -55 to 260C
AWG 22-12


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