FED-STD-228A
4.4 Any covering shall be removed from the surface of the insulation of a single-conductor cable
specimen for a distance of about 1 inch from each end. The ends shall be dipped into melted paraffin or
other suitable material to minimize the effect of moisture in reducing insulation resistance between the
covering and the conductors. In the case of multiple-conductor cable the conductors shall be separated
at each end of the specimen and the ends treated as described for single-conductor cable. In the case of
lead-covered cable the lead shall be stripped back for a distance of 3 or 4 inches at each end of the
specimen. The specimen shall be placed in the low temperature chamber at the required temperature for
the required period of time.
4.5 Immediately after the end of this period, the specimen shall be removed from the low temperature
chamber and a segment of its length bent through an arc of 180° around a mandrel of the size required in
table I. It shall be straightened and the same segment bent 180° in the opposite direction around the
mandrel. The specimen shall be bent at a uniform rate so that the time of bending shall not exceed 0.5
minute. The specimen shall be held so that rotation about the length axis of the segment does not occur
during the bending operation.
4.6 Immediately after the second bending, the bent specimen shall be subjected to the voltage withstand
test as described in method 6111.
4.7 A flat twin cable shall be bent on the minor axis of its cross section only. The minor diameter shall be
used in arriving at the size of the mandrel.
5. RESULTS
5.1 Unless otherwise specified in the detail specification, one specimen from each inspection unit shall
be tested.
5.2 Whether the insulation of the specimen withstood the specified test voltage without failure shall be
recorded.
5.3 The voltage withstand of the insulation of the inspection unit shall be the result obtained from the
specimen tested.
5.4 The test voltage, temperature, and time of exposure shall be recorded.
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