2. Disconnectors

2.1 General

Disconnectors are used to isolate a portion of a circuit on which work is to be carried out or which is to be de-energized. They are safety devices that can be electrically and mechanically locked in the open position and, in the case of conventional equipment, have a visible break in the air.

• Because of their role as safety devices, their dielectric voltage is characterized by :

  • a resistance between input and output greater than the resistance to earth, so that an excessive overvoltage preferably leads to an earth fault and not to a crossing of the isolating distance;

  • higher dielectric strength between input and output than circuit breakers...