This test is performed on cables which are anticipated to be flexed in use; it evaluates the ability of the cable to withstand repeated and reversing torsional motion while subject to a specified temperature.
The cable sample is mounted vertically into the testing apparatus with a clamp at the top and kept taught via a weight hanging from the bottom. The test fixture is placed n a temperature-controlled chamber at the specified temperature and the test may begin. The top end of the apparatus rotates 180 degrees, alternating clockwise and counterclockwise as a rate of 12 to 14 cycles per minute. This continues for a specified number of cycles or until electrical sample failure, whichever occurs first.