MIL-DTL-55425E
4.7 Electrical tests.
4.7.1 Dielectric strength, separated conductors. A five foot length of an insulated pair shall be separated by
tearing apart along the mid-rip. Three feet in the center of the piece of each insulated conductor shall be immersed in
water for one hour and a potential of 1,000V rms shall be applied between the conductors and the water, and meet
the requirements of 3.5.1.
4.7.2 DC resistance. The dc resistance of the conductors shall be determined as specified in method 6021 of
FED-STD-228 and meet the requirements of 3.5.3.
4.7.3 Dielectric strength, cable. The dielectric strength of the twisted pairs shall meet the requirements of 3.5.4 and
shall be determined as specified in method 6111 of FED-STD-228 with the following exceptions:
a. The immersion shall be four hours.
b. All the conductors connected together shall be one terminal and the other terminal shall be the water.
4.7.4 Insulation resistance. The insulation resistance of the cable shall meet the requirements of 3.5.5, and shall
be determined as specified in method 6031 of FED-STD-228 with the following exceptions:
a. The test voltage shall be not less than 100V dc.
b. The polarity of the test conductor shall be maintained negative with respect to the other conductors and the
water.
c. Each conductor shall be connected to one terminal in turn and the other terminal shall be the other three
conductors fastened together plus water ground.
d. If the measurement is made at a temperature other than 15.6 °C, the manufacturer shall correct the measured
value of insulation resistance to the resistance at 15.6 °C. However, if the insulation resistance is equal to or
greater than that required by 3.5.5 when the measurement is made at a temperature greater than 15.6 °C, no
correction factor need be employed. The manufacturer shall demonstrate that the correction factor is
accurate for his compound.
e. The insulation resistance test may be terminated in less than one minute if the galvanometer or meter has
ceased fluctuating and the reading indicates that a steady insulation resistance value has been obtained.
However, readings obtained on 5% of the lengths after one minute electrification shall be recorded to
establish a continuous check of quality.
4.7.5 Mutual capacitance. Following the test of 4.7.4 and while the cable is still immersed, measure the mutual
capacitance between the conductors of each pair at a frequency of 1,000Hz to determine compliance with the
requirements of 3.5.6.
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