Insulation Wrap Back Test
Mechanical FOR: Insulation $940During normal operation and maintenance cycles wire/cable are subjected to stresses, both mechanical and environmental, that challenge the integrity of wire/cable insulation. The wrap back test subjects wire/cable specimens to a very tight bend diameter in addition to conditioning at elevated temperatures to determine if a specific insulation is prone to cracking. A specimen is considered to have passed if, after elevated temperature exposure, the insulation has any visually detectable cracks or identifiable damage.
Procedure
- Perform visual examination of the specimen. Record any defects.
- Firmly wrap the specimen upon itself for four close turns.
- Condition the specimen as determined in the test specification (specimen conditioning typically includes elevated temperature exposure for several hours).
- After conditioning, examine the specimen and record observations.
Covered specifications
- AS4373 Method 708
- AS22759 Section 5.7.2
- AS85485 Section 4.7.29
- MIL-STD-2223 Method 2003
- AS81044 Method 4.7.5.8.2
- AS22759 Method 4.5.8.2