Difference between circuit breaker and Isolator

A circuit breaker is a device for the limiting of current supplied to a circuit.  Circuit Breaker is a device which can

• Make or break circuit under normal conditions either manually or through remote control.
• Break circuit automatically under faulty conditions.
• Make or break circuit under faulty conditions either manually or through remote control.

Some types of circuit breakers are Air blast circuit breakers, Vaccum Circuit Breakers, SF6 Circuit Breakers etc. You can notice the circuit breakers near to the transformers. Next time, when you will see a transformer search for the circuit breaker. Mostly it will be SF6 Circuit Breakers.

Isolator or Isolating Switch is a device which is used to disconnect a part of the system for maintenance purpose and repairs. Isolator can open a circuit under no load condition only. If two isolators are connected on either sides of circuit breaker, or then the circuit breaker must be opened before opening the isolators.

After performing maintenance work on the circuit breaker, isolators must be closed first and then the circuit breaker must be closed to bring the system into operation.

What is the difference between Isolator and Circuit Breaker?
• Isolator is an off-load device while, circuit breaker is an on-load device.
• Isolator is a switch operated manually, which separate the circuit from the power main and discharges the trapped charges in the circuit.
• Circuit breakers operate automatically, triggered by electromechanical mechanism inside and are a safety feature for abnormal loads and voltages in the circuit.