What is M27500?
M27500 cable is a popular mil-spec wire designed for use as low voltage power cable or signal cable in avionics and aircraft applications. Although this mil-spec has technically been replaced by the NEMA WC 27500 cable specification, many people in the industry still refer to these cables by their mil-spec.
MIL-DTL-27500 cable is offered in a variety of constructions, and if you’re unfamiliar with these cables, it can be time-consuming deciding on the perfect fit for your application. Luckily, most of the wire’s features are included right in the part number. M27500 wire part numbers can be broken down into seven sections:
- Part Identification Number (PIN)— Every part number begins with M27500, showing that the part follows the MIL-C-27500 specification.
- Identification Method— This single character tells you the wire’s color-coding, identification sequence, and the percent coverage offered by the shield. M27500 Wire is available with 85% or 95% shield coverage, and with identification methods like striping, color bands, or printed numbers.
- Conductor Size— This number identifies the AWG size for all the wires in the cable.
- Basic Wire Specification— A one or two-letter code tells you the SAE or military specification for the cable’s inners. For example, the letter “E” is the code for an AS22759/2 component, and “JA” represents an M25038/1 component.
- Number of Conductors— This number shows how many conductors are in the cable. Shielded M27500 cables can have anywhere from one to fifteen conductors, and unshielded versions can have two to fifteen conductors.
- Shield Description— A single letter tells you the shield style and material, along with its maximum temperature rating. M27500 cable can be shielded or unshielded. Shielded cables can have single or double shields with round or flat constructions, and are available in a wide range of materials, rated from 150°C to 400°C.
- Jacket Type— The jacket type is given as a two-digit number, representing a single jacket or a double jacket. Cables with a single jacket only have an outer jacket. Cables with double jackets are designed with a jacket between a double shield and a jacket covering the outer shield. From this two-digit number, you can learn both the jacket material and the maximum temperature rating for the jacket material.
For example, let’s break down M27500-26RC1S09:
- M27500— Meets the M27500 cable specification
- "-" — The dash represents the preferred identification method, according to the spec. For this cable, the insulation on the single conductor would be white. (If this cable had more than one conductor, the dash would let us know that the first wire would be white; conductors 2 -10 would each have a colored stripe, and conductors 11 -15 would have double stripes.)
- 26— The conductor size is 26 AWG
- RC— AS22759/11 inners
- 1— Single conductor cable
- S— Silver-Coated Copper round single shield, rated for up to 200°C
- 09— White Extruded Fluorinated Ethylene Propylene (FEP) jacket with a maximum temperature rating of 200°C
Now that you can read M27500 cable part numbers, selecting the appropriate wire for your application will be a lot easier. Allied Wire & Cable is QPL Approved to manufacture many M27500 cables in accordance with WC27500-2012. Design your own Mil-C-27500 Cable with Allied’s NEMA WC 27500 Part Number Builder or search our large selection of M27500 Wire.