What is the difference between circuit breaker & Isolator?

The circuit breakers and isolators serve a common purpose of circuit interruption.

They are devices that are used to disconnect a portion of the circuit from the main supply. An isolator is a device that disconnects a portion of the circuit from the main supply when there is a fault in the circuit.

It is an off load device, whereas Circuit Breakers are protection devices, similar to fuses, that protect the equipment from overload and short circuit faults throughout its operation.

Isolators can be operated only during offload conditions. Circuit breakers can be operated during both on-load and offload conditions.

Circuit breakers are meant for the protection of a circuit or equipment from short circuit and overload faults while they are in operation.