Is 9921 692d6s

IS : 9921 (Part I ) – 1981

(PREVIEW)

Indian Standard SPECIFICATION FOR ALTERNATING CURRENT DISCONNECTORS ( ISOLATORS ) AND EARTHING SWITCHES FOR VOLTAGES ABOVE 1000 V PART I GENERAL AND DEFINITIONS

1. SCOPE 1.1 This specification applies to alternating current disconnectors and earthing switches, designed for indoor and outdoor installation, for voltages above 1 000 V and for the service frequency of 50 Hz. 1.2 The specification also applies to the operating devices of these disconnectors and earthing switches and their auxiliary equipment. 1.3 This specification does not deal with additional requirements for disconnectors and earthing switches in enclosed switchgear and controlgear, as these are covered by separate Indian Standards. 1.4 -Disconnectors in which a fuse is an integral part are also not covered by this specification. 1.5 This specification ( Part.1 ) covers the general aspects and definitions applicable to disconnectors and earthing switches.