Question

Which of the following circuit breakers has lowest operating voltage?
1. Air-break
2. Bulk Oil
3. SF₆
4. Vacuum

Answer 1

Correct Answer - Option 1 : Air-break

Type of circuit breaker	Medium	Operating voltages
Air break	Air at atmospheric pressure	Low voltage up to l000 V
Tank type oil circuit breaker	Oil	Up to 33 kV
Minimum oil circuit breaker	Oil	36 kV, 1500 MVA 132 kV, 3000 MVA
Air blast	Compressed air	132 kV, 220 kV 400 kV, 760 kV
SF6	SF6 gas	132 k V, 220 kV 400 kV, 760 kV
Vacuum C.B.	Vacuum	11 kV. 33 kV
High voltage direct current C.B.	Vacuum or SF6 gas	± 500 kV DC