SOLUTION

In order to disconnect a part of the power system for maintenance and repair purposes, isolating switches are used. These are operated after switching off the load by means of a circuit breaker. The isolators are connected on both sides of circuit breakers Thus to open isolators, circuit breakers are to be opened first.

An isolator is a off-load device that is employed only for isolating the circuit when the current has already been interrupted. They ensure that the current is not switched into the circuit until everything is in order. Isolator operates under no-load conditions. They are not equipped with any arch-quenching device and don’t have any specified current breaking capacity or current making capacity.