MIL-DTL-13486E
4.7.4.2 High voltage to ground. The separator, insulation, braid, tape or wrap, sheath, and shielding
shall be removed from each end of the test specimen leaving the conductor ends bare for a length of one
to two inches. The specimen shall be formed into a loop with the ends of the conductors twisted together.
If class B cable is being tested, the individual conductors shall be electrically connected. The loop shall
be immersed in salt water containing 5% sodium chloride, by weight. No less than 3 inches (76.2 mm)
nor more than 6 inches (152 mm) of each end of each specimen shall protrude above the surface of the
salt water. Except as specified in 4.7.4.8.1 for the liquid immersion test (salt-water specimens), the
specimen shall be conditioned in the salt water for five hours. An alternating current voltage with a
frequency of 60 Hz shall be applied between the (uninsulated) conductor(s) and the water for not less
than one minute. The voltage shall be as specified in table IV. Cables which have two or more
conductors of different sizes falling under different test voltages in table IV shall be tested at the higher
voltage. The specimen shall be observed for physical signs of breakdown.
4.7.4.3 High voltage between insulated conductors (class B only). After external shielding is
removed, the sheath, tape or wrap, and filling compound shall be removed from both ends of the
specimen for a length sufficient to perform the test. Any internal shielding or cloth braid that becomes
exposed shall be removed also. A length of insulation and separator sufficient to make electrical contact
shall be stripped from all the loose, insulated conductors on one end. Suitable electrical connectors may
be attached for convenience. All of the insulated conductors except one shall be grounded. The sheath
and the remaining internal shielding shall be insulated from ground. The ungrounded, insulated
conductor shall be physically separated from the other insulated conductors to prevent arcing through the
air. An alternating current voltage of 6,000 V rms with a frequency of 60 Hz shall be applied to the
ungrounded conductor for one minute. The same process shall be repeated with each conductor
ungrounded. The specimen shall be observed for physical signs of breakdown.
4.7.4.4 Fungus resistance. The specimens shall be subjected to fungus as specified in ASTM G21.
During qualification testing, one specimen shall be removed from incubation after 30 days and subjected
to the test specified in 4.7.4.2. One specimen shall be removed from incubation after 60 days and
subjected to the same test. The remaining specimens shall be removed from incubation after 90 days
and subjected to the same test.
4.7.4.5 High temperature resistance. The insulated conductor(s) shall be stripped for a distance of
one inch at each end of the specimen. The test specimen shall be suspended around a mandrel having a
diameter of not more than five times the nominal cable diameter. A weight of not less than five pounds
for each 1/4-inch of cable diameter shall be attached to each end of the sample. The specimen, on the
mandrel with the weights freely suspended, shall be placed in a circulating air oven maintained at
250±2 °F for a period of 120 hours. At the conclusion of the 120-hour period, the specimen shall be
removed from the oven and allowed to cool to room temperature. When cool, the weights shall be
removed from the specimen and the specimen shall be removed from the mandrel. The bent portion of
the specimen shall then be bent again not less than 180 degrees (°) around the mandrel in the opposite
direction with the opposite side of the cable in contact with the mandrel, at a uniform rate such that the
complete 180° bend is accomplished in 10 seconds. After being subjected to the remaining qualification
or control tests specified for the specimen, the specimen shall be inspected for evidence of breakdown of
the insulation and sheath. The insulated conductor(s) shall then be stripped and inspected for evidence
of pitting or corrosion.
4.7.4.6 Low temperature resistance (cold bend). The specimen shall be laid out straight in a suitable
low temperature chamber and shall be subjected to an ambient temperature of -65±3 °F for 96 hours. At
the conclusion of the refrigeration period and while at -65±3 °F, the specimen shall be bent 180° around a
mandrel having a diameter of not more than 10 times the nominal outside diameter of the specimen, at
the uniform rate of one 180° bend in 10 seconds. The specimen shall not show evidence of cracking,
breaking, separation, or other damage.
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