MIL-DTL-49055F
4.6.2 Electrical tests. It shall be permissible to wind finished cable on testing spools and reels for
electrical tests, and to rewind on shipping spools and reels after completion of the last test.
4.6.3 Insulation flaws. All cable shall be subjected to the insulation flaws test in accordance with
method 6211 of FED-STD-228 with the following exceptions and conditions. The cable conductors shall
be electrically tied together and grounded. A suitable fault-signaling device for detection of insulation
flaws shall be provided. Any flaws detected shall be removed.
4.6.4 Dielectric withstanding voltage. The cable shall be tested in accordance with ASTM-D3032, with
the following exceptions: The specimen shall be 26±.062 inches (914±1.6 mm) in length and shall be
prepared for high-voltage connection by isolating adjacent conductors from each other. This may be
accomplished by carefully cutting into the ends of the specimen .5 and 1.5 inches (13 and 38 mm),
respectively, so that adjacent conductors can be bent to opposite sides of the specimen. Remove
.25 inch (6.4mm) of insulation from the 1.5 inch (38 mm) end for electrical connections. For the first part
of the test, the specified voltage (see 3.1) shall be applied between all conductors electrically connected
together and the solution, and for the second part, between each conductor and its adjacent conductors.
This may be accomplished by bussing together all conductors bent to one side of the specimen and
connecting one high-voltage lead. The conductors bent to the other side shall be treated in a similar
manner and connected to the other high-voltage lead. The center 12 inches (308 mm) of the specimen
shall be immersed for one hour. Following the test, the specimen shall be examined. Tests shall be run
before and after each test specifying dielectric withstanding voltage. When dielectric withstanding voltage
and insulation resistance tests are performed on the same samples, the tests may be done in the
following sequence:
a. Insulation resistance conductor to conductor in air.
b. Dielectric strength conductor to conductor in air.
c. Immerse samples in salt-water solution.
d. Insulation resistance conductor to solution.
e. Dielectric strength conductor to solution.
4.6.5 Insulation resistance. The specimen shall be prepared in accordance with 4.6.4. A potential of
500+50, -0 volts dc shall be applied for one minute between each conductor and its next adjacent
conductor(s) in air. Following this test, the sample shall be immersed to within 6 inches (152 mm) of its
ends in the water bath described in 4.6.4 at room temperature for a minimum of one hour. A voltage of
500+50, -0 volts dc shall be applied for one minute between the conductors and water. Insulation
resistance, calculated from the equations shown below, shall meet the applicable requirement.
Wire to wire
Specimen resistance X sample length X (no. of conductors-1)
megohms 1,000
=
(megohms)
(2 feet)
feet
1,000
Wire to water
Specimen resistance X immerse length X (no. of conductors)
megohms 1,000
=
(megohms)
(1 foot)
feet
1,000
4.6.6 Conductor resistance. The dc resistance of the individual conductors of each specimen, 36 to 48
inches (965 to 1020 mm) long, shall be tested in accordance with method 6021 of FED-STD-228, and
calculated for performance. The cable shall meet the applicable requirement.
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