scope:

Type of equipment

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

Production

The production of the enclosures shall be in accordance with documented welding procedures which shall be carried out by well trained and supervised welding personnel. Where international standards (ISO or CEN) are not available, National Standards may be used.

NOTE. This standard will be revised as soon as possible when ISO or CEN standards covering the various aspects are available.