Materials providing insulation from electric shock shall be adequate.Compliance is checked by subjecting the insulating material for 1 min to 750 V with a substantially sinusoidal wave form having a frequency of 50 Hz or 60 Hz. This provision does not exclude the testing of the material as situated within the tool, providing care is taken to ensure that materials not under consideration are not subjected to the test voltage.This test applies only to materials which, if they were to fail to insulate, would subject the user to a shock hazard from a hazardous voltage. This test does not apply to materials that provide only a physical barrier to contact. As such, an uninsulated energized part shall be within 1,0 mm of the material surface to be considered for this requirement.