This specification deals with insulation levels for all equipment for alternating current systems having nominal voltages above 1 kV, with the exception of generators and other rotating machines, underground cables and overhead lines. Its object is to standardize the insulation level of the various equipments, of both outdoor and indoor design, to be used in a given installation. Test procedures suitable for particular types of equipment are specified in the relevant Australian standards, and the values of test voltages specified therein should comply with the scale of standardized insulation levels given in Section 3 of this specification.