This International Standard is applicable to high-current testing and measurements on both high-voltage and low-voltage equipment. It deals with steady-state and short-time direct current (as e.g. encountered in high-power d.c. testing), steady-state and short-time alternating current (as e.g. encountered in high-power a.c. testing), and impulse-current. In general, currents above 100 A are considered in this International Standard, although currents less than this can occur in tests. NOTE This standard also covers fault detection during, for example, lightning impulse testing. This standard: • defines the terms used; • defines parameters and their tolerances; • describes methods to estimate uncertainties of high-current measurements; • states the requirements which a complete measuring system shall meet; • describes the methods for approving a measuring system and checking its components; • describes the procedure by which the user shall show that a measuring system meets the requirements of this standard, including limits set for uncertainty of measurement.