scope:

This standard is applicable to three-phase alternating-current switches, having making and breaking current ratings, for indoor and outdoor installations, for rated voltages 52 kV and above; and for rated frequencies up to and including 60 Hz. 

This standard is also applicable to the operating devices of these switches and to their auxiliary equipment.

Notes 1. - Switches for gas insulated switchgear are covered by this standard.

2. - Switches having a disconnecting function and called switch-disconnectors are also covered by IEC Publication 129.

3. - Earthing switches are not covered by this standard. Earthing switches forming an integral part of a switch are covered by IEC Publication 129.

Object

The main object of this standard is to establish requirements for switches used in transmission and distribution systems. General-purpose switches for this application shall comply with the following service applications:

- carrying rated normal current continuously;

- carrying short-circuit currents for a specified time;

- switching of mainly active loads;

- switching of no-load transformers;

- switching of the charging current of unloaded cables, overhead lines or busbars;

- switching of closed-loop circuits;

- making short-circuit currents.

A further object of this standard is to establish requirements for limited-purpose and special-purpose switches used in transmission and distribution systems.

Limited-purpose switches shall comply with one or more of the service applications indicated above.

Special-purpose switches may comply with one or more of the service applications indicated above and, in addition, shall be suitable for one or more of the following applications:

- switching single capacitor banks;

- switching back-to-back capacitor banks;

- switching shunt reactors including secondary or tertiary reactors switched from the primary side of the transformer;

- applications requiring an increased number of operating cycles;

- switching under earth fault conditions in systems with isolated neutral or in resonant earthed systems.