This standard is applicable to measuring relays and protection equipment for power system protections, including the control, monitoring and process interface equipment used with those systems (hereinafter named "apparatus"). For equipment not incorporating electronic circuits e.g. electromechanical relays, emission and immunity tests are not required. This standard specifies the essential requirements for electromagnetic compatibility for apparatus intended to be used at industrial locations. Apparatus used in substations and power plants may require higher immunity test levels, or additional tests, specified in the EN/IEC 60255-22 or EN/IEC 61000-4 or other EN standards. All tests in this standard are type tests.