1. Scope

This Standard applies to cast aluminium alloy enclosures pressurized with dry air, inert gases, eg. sulphur hexafluoride, carbon tetrafluoride, or nitrogen or a mixture of such gases, used in indoor or outdoor installations of high-voltage switchgear and controlgear, where the gas is used principally for its di electric and/or arc-quenching properties, with rated voltages (1) 1 kV and up to and including 52 kV and with gas-filled compartments with design pressure greater than 3 bar (gauge); and (2) 72.5 kV and above.

The enclosures comprise parts of electrical equipment not necessaril y limited to the following examples:

Circuit-breakers Switch-disconnectors Disconnectors Earthing switches Current transformers Voltage transformers Surge arresters Busbars and connections

The scope also covers pressurized components such as the centre chamber of live tank switchgear, gas-insulated current transformers, etc.

Canadian Deviations are included in this Standard.