Conduits used in electrical installations shall possess adequate mechanical strength. One of the tests used for ascertaining the mechanical strength of conduits is the bending test.
For rigid steel conduits, the test for bending is carried out by holding one end of a test specimen taken from the sample of conduits under test in a fixed holder and bending it over a grooved circular mandrel through an angle of 90°. During this operation, the test specimen is guided on its outer side by a grooved roller so that it follows the contour of the mandrel. The test specimen is then checked for effects of bending on it.
The Bending Tester for Rigid Steel Conduitsconsists of an arrangement to mount grooved mandrels of specified sizes on a rigid platform and a pivoted lever to bend the test specimens against it through an angle of 90°.
The mandrel mounting arrangement has a central pivot pin about which semi-circular mandrels can be fitted with the help of allen bolts so that they are held rigidly. The mandrel for testing 16 mm diameter conduits is fixed permanently on the platform. Additional mandrels can be fitted over it to enable conduits of 20 and 25 mm diameter to be tested.
IS 9537 (Part 2) - 1983 : Specification for Conduits for Electrical Wiring
Part 2 : Rigid Steel Conduits