IEC 60981-2019 pdf free.Extra heavy-duty electrical rigid steel conduits.
6.1.2 Organic coatings test
An organic coating used to protect the interior of the conduit shall not crack,flake off or beotherwise damaged.
Compliance shall be checked by the following test:
The coating shall be applied to a sheet-steel test piece and baked in an oven for 5 h, andshall withstand without damage ten successive bends of the test piece back and forth throughan angle of 180° against an edge having a radius of 1,6 mm.
The apparatus shall consist of flat test pieces of sheet steel of a width of 75 mm by a length of125 mm and a thickness of approximately 0,25 mm,an oven for baking the test pieces,and avice with jaws of a width of at least 75 mm for holding the test pieces during the bending test.The 75-mm edge of each jaw shall be rounded to a radius of 1,6 mm.
Two test pieces shall be cleaned with a suitable organic solvent to remove any grease andforeign material and shall then be dipped in the organic coating. After air drying for 30 min,the test pieces shall be suspended by means of short wires in the oven. Samples shall bebaked for 5 h at the normal baking temperature for the organic coating in question but, if thenormal baking temperature is lower than 135°C or the enamel is regularly air dried, the oventemperature shall be maintained between 135 C and 150°℃.
At the end of 5 h, the test pieces shall be removed from the oven and cooled in still air toroom temperature.Each flat test piece shall be secured in the vice,gripped at its free end.and then bent for 90° against one of the 75-mm edges of the vice jaws.Each test piece shallthen be bent back past its original position through 180° so that it ends bent 90° against theother 75-mm edge of the vice jaws. lt shall then be bent for 90° in the opposite direction,ending with the test piece in its original position.This cycle shall be repeated five times.IEC 60981 pdf download.