This part of IEC 62271 specifies requirements for gas-insulated metal-enclosed switchgear in which the insulation is obtained, at least partly, by an insulating gas or gas mixture other than air at atmospheric pressure, for alternating current of rated voltages above 52 kV, for indoor and outdoor installation, and for service frequencies up to and including 60 Hz. For the purpose of this standard, the terms GIS and switchgear are used for gas-insulated metal-enclosed switchgear . The gas-insulated metal-enclosed switchgear covered by this standard consists of individual components intended to be directly connected together and able to operate only in this manner. This standard completes and amends, if necessary, the various relevant standards applying to the individual components constituting GIS.