MIL-DTL-3702F
4.7.3.1 Tensile load. A test specimen consisting of a 3-foot (.914 m) length of unshielded or shielded
cable from which the shielding has been removed shall be clamped in a test setup similar to that shown
on figure 1. A dead weight load equivalent to 55 pounds shall be applied to that portion of the cable being
tested for a period of one minute. At the conclusion of one minute, the specimen shall be inspected for
evidence of mechanical rupture or of separation of components. Each end of the test specimen shall be
stripped of insulation for 1 inch (25.4 mm). The bare ends of the conductor shall be twisted together
causing the specimen to assume the shape of a loop. That portion of the test specimen that was
subjected to the tensile load shall be immersed, bare conductor ends up, in a grounded, 5 percent (by
weight) aqueous sodium chloride solution (common salt in water), at room temperature, for 30 minutes.
The ends of the specimen shall protrude 3.25±.25 inches (82.5+ 6.35 mm) above the surface of the
solution as shown on figure 2. After soaking, and while still immersed in the salt solution, voltage at 60
Hz, shall be applied between the conductor and the solution beginning at zero voltage and increased at 1
kilovolt rms per each 5 seconds to not more than 15 kilovolts rms. The applied voltage shall be held for 5
minutes. At the conclusion of the voltage application, the specimen shall be removed from the solution
and inspected for insulation failure.
4.7.3.2 Maximum voltage. The test cable shall be prepared as specified on figure 3 and subjected to
the potential as specified, at 60 Hz, at room temperature, applied between the cable conductor and the
mandrel and metal test sleeves. The potential shall be increased 1 kilovolt rms per second from zero until
the specified potential is reached.
4.7.3.3 Insulation flaws. During the process of manufacture, each length of cable shall be subjected
to the insulation flaws test. The entire length of cable shall be passed through a suitable beadchain or
fine, link-mesh, electrode-spark device applied to 100 percent of the surface of the cable that shall
provide not less than 30 kilovolts rms at 60 Hz. Every point on the surface of the cable shall be in contact
with an electrode for a period of not less than .6 second. An examination shall be made for evidence of
flaws such as cracking, wear, and similar signs of loss of insulation integrity.
4.7.3.4 Capacitance. A test specimen consisting of 1 piece of completed cable, not less than 36
inches (914 mm) in length, shall be dried in an oven at a temperature of 176±4°F for 18 hours. After
removal from the oven and cooled to room temperature, the specimen shall be immersed in water with
each end of the specimen protruding 2 inches (50.8 mm). The capacitance shall be measured between
the conductor of the specimen and the water by means of a capacitance bridge, at a frequency of 1,000
Hz.
4.7.3.5 Life cycle. The life cycle test specimen shall consist of a 6-foot (1.83 m) length of completed
cable for test applications other than Air Force aircraft. (For Air Force aircraft test application see 4.4.1
and 4.7.3.5.4). The life cycle tests shall be performed in the order and sequence as follows.
4.7.3.5.1 Flexing. The test specimen shall have a 10-pound weight firmly attached to one end of the
conductor. The free end of the specimen shall then be firmly attached to a smooth, cylindrical mandrel in
such a manner that the specimen with attached weight is permitted to hang freely. The mandrel shall be
rotated at a rate of 20 turns per minute against the gravitational pull exerted by the suspended weight,
winding the cable around the mandrel with the coils touching. The specimen shall then be unwound, and
rewound in the opposite direction, with the opposite side of the specimen in contact with mandrel. During
winding, the specimen shall not be constrained against normal twisting. The above procedure shall be
repeated once. The diameter of the mandrel shall be .375 inch (9.5 mm) for cable diameter 5 and .50
inch (12.7 mm) for cable diameter 7.
17
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business