What is different Circuit Breker And Isolater?

Answer 1

I think that the questioner is asking what is the difference between an isolator and a circuit breaker.

A circuit breaker is a switching device designed to interrupt a fault current.

An isolator is not intended to break a live circuit but, rather, to provide a visible separation between a circuit component and live conductors.

For example, isolators (or 'disconnectors' in US parlance) are located on either side of a high-voltage circuit breaker. If the circuit breaker requires maintenance, then the procedure is to:

a. trip the circuit breaker.

b. open the isolators on each side of the circuit breaker, so there is a visible gap between the circuit breaker and the 'hot' conductors.

c. apply temporary earths (grounds) between each isolator and the circuit breaker.

d. complete a 'permit to work' card.

e. begin work.

Answer 2

Circuit breakers are overcurrent protective devices, so must be capable of interrupting a fault current, and closing onto a fault, without damage to the circuit breaker. Circuit breakers are also used to interrupt load currents. Isolators are generally designed to disconnect circuits on 'no load' -that is when there is no current is flowing through the circuit; their function is simply to provided a physical break between the load and the supply once the circuit has been interrupted by a load-breaking device such as a circuit breaker.

Answer 3

A circuit breaker is designed to (a) interrupt load current, and (b) to interrupt a fault current. An isolator(called a 'disconnector' in North America) is not designed to interrupt a current, but to provide a visible break in a circuit, after the current has already been interrupted.

Answer 4

An isolator is not designed to interrupt a load current and, so, is opened after a circuit has been interrupted using a circuit breaker, and closed before a circuit breaker restores that circuit. An isolator is used to provide a visible break between the part of the circuit on which work is to be carried out, and any energised part.

A circuit breaker is designed not only to interrupt a load current, but to interrupt and close onto a fault current, which is many time greater in magnitude than a laod current.