when the power is to be supplied
when the line is to be tested
when the switch is to be put on
whenever fault occurs in the line
.
high dielectric strength and thermal stability
non inflammable
arc extinguishing ability
all of the above
restriking
breaking
arc
recovery
good cooling properties and absorption of arc energy
high dielectric strength
acting as an Insulator
Air blast circuit breaker
Minimum oil circuit breaker
Bulk oil circuit breaker
Sulphur hexafluoride circuit breaker