This International Standard applies to switchgear assemblies for alternating current of rated voltages above 52 kV for indoor and outdoor installations, including their supporting structure rigidly connected to the ground, and does not cover the seismic qualification of live tank circuit breakers. Switchgear assemblies do have typically low centers of gravity, e.g. gas-insulated switchgear (GIS). This first edition of IEC 62271-207 cancels and replaces the first edition of IEC 62271-2 and constitutes a technical revision. The change from IEC 62271-2 is as follows: -the minimum voltage rating was changed from 72,5 kV to above 52 kV