Circuit Breaker Questions

A circuit breaker is a switching device which can be operated manually and automatically to control and protect an electrical power system.

These are the types of circuit breakers:

• Vacuum circuit breakers
• SF6 circuit breakers
• Oil circuit breakers
• Air circuit breakers

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Important Circuit Breaker Questions with Answers

1. How is the circuit breaker classified according to the operating mechanism?

According to the operating mechanism of the circuit breaker, it is classified as:

• Hydraulic circuit breaker
• Spring-operated circuit breaker
• Pneumatic circuit breaker

2. Which are the contact materials in the vacuum circuit breakers?

In vacuum circuit breakers, silver-bismuth, copper-lead, silver-lead copper-tellurium, and copper-bismuth materials are used as the contact materials in the vacuum circuit breakers.

3. Suppose the circuit breaker becomes very hot. Is it the sign of a bad circuit breaker?

Yes, if the circuit breaker becomes very hot, it might lead to wear and tear and result in the burning smell of the electrical panel.

4. When a larger than intended electricity exists through a conductor, this results in excessive generation of heat and damage to equipment. This condition is known as ______

1. Over current
2. Large current
3. Excess current
4. Option a) and c)

Answer: d) Option a) and c)

5. State true or false: A circuit breaker cannot be reset to resume normal operation.

1. TRUE
2. FALSE

Answer: b) FALSE

Explanation: A circuit breaker can be reset to resume normal operation either manually or automatically.

6. What is the abbreviation of OCPD with respect to circuit breakers?

1. Outlook Protection Device
2. Overrating Protective Device
3. Overcurrent Protection Disk
4. Overcurrent Protection Device

Answer: d) Overcurrent Protection Device

Explanation: OCPD is abbreviated as Overcurrent Protection Device.

7. Choose the correct answer: Is fuse an OCPD?

1. Yes
2. NO

Answer: a) Yes

Explanation: Fuse is an excellent Overcurrent Protection Device.

8. Give three examples of Overcurrent Protection Devices.

Circuit breakers, overcurrent relays, and fuses are examples of overcurrent protection devices.

9. Does the circuit breaker help in switching during short circuit conditions?

Yes, switching during short circuits and earthing is offered by the circuit breaker to protect the equipment.

10. Write a disadvantage of the circuit breaker?.

The disadvantage of the circuit breaker is that it is sensitive to the variation in voltages.

Practice Questions

1. What is a circuit breaker?
2. What are the advantages of circuit breakers?
3. What are the disadvantages of the circuit breaker?
4. What are the types of circuit breakers?
5. Define oil circuit breakers.