Which of the following correctly represents the sequence of operations of isolator circuit breaker and earthing switch while opening a circuit
- A. Open circuit breaker - open isolator - close earthing switch
- B. Open isolator - close circuit breaker - open earthing switch
- C. Close earthing switch - open circuit breaker open isolator
- D. Close circuit breaker - close isolator - open earthing switch.
Answer: A. Open circuit breaker - open isolator - close earthing switch
Explanation: While opening a circuit: first open the circuit breaker (interrupter of load/fault current), then open the isolator (under no-load), and finally close the earthing switch (to safely discharge trapped charges).