power systems

dear guest

first similarities

both are for the switching operation

now difference

how & when they will operate this creates difference between them

1. traditional isolator have to operate when line is at no load or dead condition

at the same place CB can operate even in fully loaded or faulty condition

2. CB is provided with the arc quenching arrangement

& there is no arc quenching arrangemet along with the isolator so we cant

operate it in loaded or faulty condition

feel free to ask more

The term isolator can have several meanings. For example an isolator (or disconnector) may be installed in the line or ground leads of distribution class surge arresters to physically disconnect the arrester from the system in the event of an arrester failure to prevent line lockout. The fault due to the failed arrester must be initially cleared by a circuit breaker or recloser but the line will remain in service when the breaker is reclosed. Surge protection will be lost until that arrester is replaced but the disconnected lead provides visual evidence that the arrester has failed.

I have also seen sectionalizers called isolators because they isolate a faulted section of the distribution system and limit the affected area.