This standard applies to welded composite enclosures of cast and wrought aluminium and aluminium alloy 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 of 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 pressurized components such as the centre-chamber of live tank switchgear and controlgear, gas-insulated current transformers, etc.