MIL-DTL-55021D simplified

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(Example of a three conductor, M55021 Cable)

M55021 cable is military rated cable intended for use in the wiring of electrical equipment and components.

Recently being adopted by NEMA under the ANSI/NEMA WC 55021-2013 standard, M55021 cable was most commonly referred to as the MIL-DTL-55021 specification. The specification can still be found at the DLA website along with it’s most recent revisions.

The jacket materials called out in the M55021 spec decide the operating temperature of the cable itself. For example, PVC (Polyvinylchloride) ranges from -40°C to 105°C operating temp. Where the Fluoropolymer jacket types FEP (Fluorinated ethylene propylene) and PTFE (Polytetrafluoroethylene) range for -65°C to 200 °C temp rating.

An example of our the part number sequence for the M55021 specification is constructed is as follows:

Part number: B24C904-903-902P

M55021_Breakout

The part number components are all defined per the specification:

  • Wire Type – This is the base wire used in building the cable. The base components are built using M16878 specs (or newer NEMA HP3 standards). Please contact us for specification details or questions you might have.

The letters that designate the base wire used are:

Letter Wire Specification Letter Wire Specification
B M16878/1 (NEMA HP7)  105°C EE M16878/5 (NEMA HP3)    200°C
C M16878/2 (NEMA HP7)  105°C BJ M16878/17 (NEMA HP7)  105°C
D M16878/3 (NEMA HP7)  105°C CJ M16878/18 (NEMA HP7)  105°C
E M16878/4 (NEMA HP3)  200°C DJ M16878/19 (NEMA HP7)  105°C
  • Conductor Size – This is the AWG size identifier of the wires used to build the cable. This table shows the conductor sizes and stranding available for M55021:
Conductor Size Stranding
26 AWG  to 30 AWG 7 Strands
12 AWG to 24 AWG 19 Strands
10 AWG 37 Strands
  • Conductor Material – This letter signifies the conductor metal in the base wires of the cable:
    • C”  =  Copper
    • S”  =  Copper Clad Steel (CCS)
    • H”  =  High Strength Copper Alloy (HSCA)
  • Wire Colors  – Wire colors consist of one to three numerals. The first number is always the base color. The second and third numbers (If present), represent stripes (Example: “926” – This would be white with red and blue stripes). The color chart below represents all of the colors used. This can also be found in Table 1 of MIL-STD-681F. The most common color codes are White (Single Conductor), White/Black (Two Conductors Twisted), and White/Black/Red (Three Wires twisted).
Code Color Code Color
0 Black 5 Green
1 Brown 6 Blue
2 Red 7 Violet
3 Orange 8 Gray
4 Yellow 9 White
  • Covering over Component Wires – The covering is the shield (If present) and and insulation jacket over the cable. All M55021 shields are made using a braid of the same materials used on the inner wires. The covering over component wires must be identified in the part number by using one of the following letter configurations below:
Letter   Covering  Letter    Covering
U No Shield or Jacket S Shielded, No jacket
P PVC (Polyvinylchloride) Jacket SP Shielded, Extruded PVC Jacket
F FEP (Fluorinated Ethylene Propylene) Jacket SF Shielded, Extruded FEP Jacket
J Polyamide Jacket SJ Shielded, Polyamide Jacket
T PTFE (Polytetrafluoroethylene) Jacket STW Shielded, Wrapped PTFE Jacket
STX Shielded, Extruded PTFE Jacket

Thank you for taking a moment to review our brief description of the M55021 specification. If you have any questions please feel free to contact us.

Phone: (775) 356-8969

Email: eng@silverstatewire.com

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