A switch is used to disconnect or close circuits that may be energized. If the circuit conducts current when it is operated, special devices need to be installed on the switch contacts to interrupt or establish the current flow. High-voltage switches are operated remotely with a mechanism or directly with a hot-line tool, called a switch stick. The operating mechanism may be manually operated at the location of the switch by a lineman or by control signals initiated by remote devices to an electric, hydraulic, or pneumatic operating mechanism, at the switch location, from a remote point.

Switches may be divided into four general classes:

1. Air switches

   1. Circuit breaker

   2. Air break

   3. Disconnect

2. Oil switches

   1. Oil circuit breaker

   2. Oil circuit recloser

      (1) Sectionalizer

3. Vacuum switches

   1. Vacuum circuit breaker

   2. Vacuum recloser

4. Sulfur hexafluoride gas (SF ₆) switches

   1. Circuit breaker

   2. Circuit switcher

   3. Recloser

The following standards provide additional information on switches:

ANSI/IEEE C37.30, Definitions and Requirements for High Voltage Air Switches, Insulators and Bus Supports

ANSI C37.35, Application, Installation, Operation, and Maintenance of High-Voltage Air Disconnecting and Load Interrupter Switches

ANSI C37.45, Specifications for Distribution Enclosed Single-Pole Air Switches

ANSI/IEEE C37.60, Requirements for Overhead, Pad-Mounted, Dry Vault, and Submersible Automatic Circuit Reclosers and Fault Interrupters for AC Systems

ANSI/IEEE C37.61, Guide for the Application, Operation and Maintenance of Automatic Circuit Reclosers

Air Switches. As their names imply, air switches are switches whose contacts are opened in air. Air switches are further classified as air circuit breakers, air break switches,...