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Which of the following sequence of operation is correct for operation of circuit breaker, isolator and earthing switch while opening a circuit ?
  • a)
    Open circuit breaker–open isolator–close earthing switch.
  • b)
    Open isolator–open circuit breaker–close earthing switch.
  • c)
    Open earthing switch–open isolator–then open circuit breaker.
  • d)
    Open circuit breaker–close earthing switch– open isolator
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
Which of the following sequence of operation is correct for operation ...
Sequence of Operation for Circuit Breaker, Isolator, and Earthing Switch while opening a Circuit

Opening a circuit requires a specific sequence of operation for circuit breaker, isolator, and earthing switch to ensure safe and effective disconnection of the electrical system. The correct sequence of operation is as follows:

Step 1: Open Circuit Breaker
The first step in opening a circuit is to open the circuit breaker. This is done by operating the circuit breaker mechanism, which interrupts the flow of current in the circuit. The circuit breaker should be opened under no-load conditions to prevent arcing and damage to the circuit breaker contacts.

Step 2: Open Isolator
Once the circuit breaker is open, the isolator can be opened. The isolator is a mechanical switch that isolates the circuit from the rest of the electrical system. It should be opened only after the circuit breaker is open to avoid arcing and damage to the isolator contacts.

Step 3: Close Earthing Switch
After the isolator is open, the earthing switch should be closed. The earthing switch is a mechanical switch that connects the circuit to the earth, providing a safe path for the fault current. Closing the earthing switch helps in discharging any residual charge in the circuit and also provides a safe working environment for the maintenance personnel.

Conclusion
The correct sequence of operation for opening a circuit involves opening the circuit breaker first, followed by the isolator and finally closing the earthing switch. This sequence ensures safe and effective isolation of the circuit from the rest of the electrical system, minimizing the risk of electrocution and damage to the electrical equipment.
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Which of the following sequence of operation is correct for operation ...
CB generally operates on loaded or SC conditions..bcz it has arc quenching medium . Isolator always work on No load bcz it doesn't have arc quenching medium. and in the last Conductor is earhthed to avoid any harm to the apparatus/individual working there
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Which of the following sequence of operation is correct for operation of circuit breaker, isolator and earthing switch while opening a circuit ?a)Open circuit breaker–open isolator–close earthing switch.b)Open isolator–open circuit breaker–close earthing switch.c)Open earthing switch–open isolator–then open circuit breaker.d)Open circuit breaker–close earthing switch– open isolatorCorrect answer is option 'A'. Can you explain this answer?
Question Description
Which of the following sequence of operation is correct for operation of circuit breaker, isolator and earthing switch while opening a circuit ?a)Open circuit breaker–open isolator–close earthing switch.b)Open isolator–open circuit breaker–close earthing switch.c)Open earthing switch–open isolator–then open circuit breaker.d)Open circuit breaker–close earthing switch– open isolatorCorrect answer is option 'A'. Can you explain this answer? for Electrical Engineering (EE) 2024 is part of Electrical Engineering (EE) preparation. The Question and answers have been prepared according to the Electrical Engineering (EE) exam syllabus. Information about Which of the following sequence of operation is correct for operation of circuit breaker, isolator and earthing switch while opening a circuit ?a)Open circuit breaker–open isolator–close earthing switch.b)Open isolator–open circuit breaker–close earthing switch.c)Open earthing switch–open isolator–then open circuit breaker.d)Open circuit breaker–close earthing switch– open isolatorCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which of the following sequence of operation is correct for operation of circuit breaker, isolator and earthing switch while opening a circuit ?a)Open circuit breaker–open isolator–close earthing switch.b)Open isolator–open circuit breaker–close earthing switch.c)Open earthing switch–open isolator–then open circuit breaker.d)Open circuit breaker–close earthing switch– open isolatorCorrect answer is option 'A'. Can you explain this answer?.
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