MIL-DTL-27072 Cable, Power, Electrical And Cable, Special Purpose, Electrical, Multiconductor And Single Shielded, General Specification ForThis specification covers special purpose electrical multi-conductor and single shielded cable for electronic circuits where the cable will be protected in racks, tunnels, or within buildings, trailers, or equipment. Cables constructed using polyvinyl chloride \(PVC\) on insulated wires or for fillers, tapes, or jackets are not to be used for aerospace applications.

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MIL-DTL-27072E

3.5.2 Component shielding (braid coverage). For the shielded components specified in 3.4a, the

shield shall consist of a woven braid using strand material specified in 3.3.5. The metallic coating on the

copper strands of the shield shall be similar to the metallic coating of the conductor to which the shield is

applied. Unless otherwise specified (see 6.2.1), metallic shielding shall provide coverage of not less than

90%. The angle of the braid with the axis of the cable shall lie between 20� and 40� for diameters up to

.600 inch (15.2 mm). For diameters larger than .600 inch (15.2 mm), the braid angle may be greater than

40�. Percent coverage, K, and angle of braid, a, shall be calculated as follows:

K = (2F - F ) x 100

F = NPd/Sin a

a = Tan (2š(D +2d) P/C)

-1

Where:

Fill or space factor

Percent coverage

Number of wires per carrier

Picks per inch of cable length

Diameter of individual braid wire in inches

Angle of braid with axis of cable

Diameter of cable under the shield in inches

Number of carriers

3.5.2.1 Strand size. Braided shields using round copper and copper alloy wires shall be as specified

TABLE VI. Braided shield strand size to covered diameter.

Strand size AWG

Diameter covered inch (mm)

to .060 (1.52)

.061 (1.55) to .310 (7.87)

.311 (7.90) to .750 (19.05)

.751 (19.08) and larger

3.5.3 Component jacketing. The jacket shall be extruded directly over the shield or binder tape if

present. The insulated wire may also include a jacket.

3.5.3.1 Jacket material applications for basic wires designated P or B . Jacket material used for a

specific basic wire designated P or B (see table II) shall be as specified in table VII.

TABLE VII. Jacket material applications.

Jacket material

Basic wire designator

Shielded components

Unshielded components

(multi-conductor cable)

Polyamide or PVC

PVC

1/ Shall not be used if the diameter of the component exceeds .250 inch (6.35 mm).

3.5.3.2 Other wire types. For components having basic wire designators not listed in table VII, the

jacket material shall be limited to materials listed in 3.3.6.