Applies to metal-enclosed switchgear the insulation of which is obtained, at least partly, by an insulating gas other than air at atmospheric pressure. It covers both indoor and outdoor installations for rated voltages of 72.5 kV and above and complements and amends as necessary the various Standards covering the individual elements of gas-insulated metal-enclosed switchgear. Contents include service conditions, definitions, ratings, design and construction, type and routine tests. It is intended to be read in conjunction with AS 2650.