This part of IEC 60512, when required by the detail specification, is used for testing electromechanical components within the scope of IEC technical committee 48. This test may also be used for similar devices when specified in a detail specification. The object of this test is to define a standard test method to determine the variation of contact resistance of electromechanical components under specified dynamic conditions. This test should be carried out only on components the contact resistance of which is measured by test 2a.