What Are M27500 Cables?
M27500 cables cover a range of specialized cables primarily intended for demanding aerospace and military applications. M27500 high-performance cables use a 16-character part number that identifies the type of cable including the number of conductors, conductor type, insulation, jacket and shielding. Rather than specifying a range of cables with similar materials, the military M27500 specification uses a wide selection of high-quality materials to meet the arduous requirements of this wire specification. M27500 cables have a maximum voltage rating of 600 volts and, depending on the specification, have maximum working temperatures between 150 Celsius and 260 C.The National Electrical Manufacturers Association manages the M27500 specification under the NEMA WC 27500 specification. All Allied Wire and Cables M27500 cables have QLP approval.
What is the NEMA WC 27500 specification?
The NEMA WC 27500 specification is a standard developed by the National Electrical Manufacturers Association (NEMA) that defines the requirements needed for certain aerospace wire used for aircraft, spacecraft, and military applications. The NEMA WC 27500 specification covers a wide array of necessary requirements in order to meet this standard; including features such as conductor size, insulation construction, temperature ratings, resistance features such as chemical or fire resistance, physical durability, and more. The high performing and strict standards that NEMA WC 27500 wire requires makes it a great choice for not only military use, but other high-reliability applications as well, such as in power distribution or communication systems.
What are the differences between Mil-Spec M27500 Wire and Mil-Spec M22759 Wire?
Although both M27500 and M22759 used in similar military and aerospace applications, these wires typically utilize different insulation types and are rated to different operational temperature and voltage ranges. Mil-Spec 27500 wire has a wider operational temperature range when compared to Mil-Spec 22759 wire. Mil-Spec 27500 also has a higher voltage rating than Mil-Spec 22759 wire. When comparing insulation types, Mil-Spec M27500 wire commonly utilizes a variety of insulation types based on the intended application; such as PTFE, FEP, or ETFE insulation. Mil-Spec M22759 wire typically only uses cross-linked ETFE insulation. Lastly, Mil-Spec 27500 wire may require EMI and/or RFI shielding, while Mil-Spec M22759 wire does not require shielding.
M27500 Cable Construction
M27500 cables have a wide range of material combinations, including:
M27500 cables use a selection of nickel-, silver- and tin-plated stranded copper wires. Most types have 19 strands for maximum strength and rigidity.
Number of Conductors
Although the NEMA W27500 cable specification allows for up to 15 conductors, the most common arrangements are for one to five conductors.
Most M27500 wires use an extruded fluoropolymer insulation that offers good high-temperature performance and resists abrasion, chemicals, acids, alkalis, ozone and oxidation. These include Ethylene tetrafluoroethylene (ETFE), Polytetrafluoroethylene (PTFE) and Fluoroethylene propylene (FEP)
M27500 cables may have single or double shields for electromagnetic interference (EMI) suppression. Shield ratios are 85% and 90%. Shield materials include tinned-, nickel- and silver-coated copper wire braids.
Wires may have a single or double jacket. Common jacket materials include fluoropolymers and glass or polyamide tape.
Understanding M27500 Part Numbers
A unique aspect of M27500 cables is that the part number specifies the wire type including the conductors, insulation, shield and jacket. Items covered include:
- First letter or dash: A single letter or a dash after the M27500 number indicates the type of shielding and wire color code.
- First set of numerals: These numbers show the wire size in American Wire Gauge.
- Next one to two letters: The cable specification in terms of Society of Automotive Engineers (SAE) specifications.
- The second set of numerals: The number of conductors in the cable.
- Next letter: This letter identifies the type of shield and whether it’s a single or double shield.
- Last two digits: The last digits indicate the type of jacket.
Use this AWC M27500 part builder to obtain additional information regarding how to specify these unique cables.
You can use NEMA W27500 wire for demanding military and civilian aerospace, avionics and airframe applications to a maximum voltage of 600 volts. Depending on the specification, the maximum usable temperature varies from 150 C to 260 C.
M27500 General specifications
- Conductors: Stranded nickel-, silver-, or tin-plated stranded copper wires
- Insulation: Mainly chemically inert fluoropolymer materials with good ozone and oxidation resistance
- Shielding: Single or double shield with 85% or 90% coverage
- Jacket: Fluoropolymer, PTFE, glass, or polyamide tape
- Maximum temperature ratings: Between 150 C to 260 C
- Voltage rating: 600 volts
- AWG sizes: 26 AWG to 10 AWG
- QLP M27500 Approval
- NEMA WC 27500
Contact us for further information regarding M27500 cable and specialized custom cable applications.