scope:

This standard applies to fusion welded wrougth steel enclosures pressurized with dry air, inert gases, for example sulphur hexafluoride or nitrogen or a mixture of such gases , used in indoor or outdoor installations of high-voltage switchgear and controlgear with rated voltages 72,5 kV and above, where the gas is used principally for its dielectric and/or arc-quenching properties. The enclosures comprise parts of electrical equipment not necessarily limited to the following examples: - Circuit breakers; - Switch-disconnectors; - Disconnectors; - Earthing switches; - Current transformers; - Voltage transformers; - Surge arrestors; - Busbars and connections. The scope also covers pressurize d components such as the centre chamber of live tank switchgear, gasinsulated current transformers, etc.