･ NOTE： Care should be taken on equipment operating below 60 V and on semiconductor devices to ensure that no damage is sustained due to the application of excessive test voltages：
･ When an insulation test is made on a circuit incorporating capacitors of a total capacitance exceeding 2 microfarads, an insulation tester of the constant-voltage type should be used in order to ensure that accurate test readings are obtained.
14.2.2 A test for insulation resistance should be applied to all permanent wiring of communications, lighting and power circuits between all insulated poles and earth and, where practicable, between poles. The installation may be sub-divided to any desired extent and appliances may be disconnected if tests give results lower than those in Table 8.
NOTE： Attention is drawn to the importance of recording the temperature of windings of rotating machines at the same time as the insulation resistance. The insulation resistance of machine windings varies considerably with temperature. Corrected values may be obtained by reference to Figure 1.
14.2.3 Before switchboards, section boards and distribution boards are put into service, their insulation resistance shall be not less than 1Megohm when measured between each busbar and earth and between each insulated busbar and busbars connected to the other pole or poles. The insulation resistance shall be recorded together with the ambient temperature and the relative humidity at the time of test.
This test shall be made with all circuit-breakers and switches open and all fuse-links for pilot lamps, earth-fault indication lamps, voltmeters, etc. removed and voltage coils temporarily disconnected.
14.2.4 The insulation resistance of generators and motors shall be measured at operating temperature immediately after running at normal load. The embedded temperature sensor of the machine if any is connnected to earth during testing. The results obtained depend not only on the characteristics of the insulation materials and on the way in which they are applied, but also on the ambient temperature and the relative humidity which shall be recorded at the time of the test.
