Circuit Breaker Viva Interview Questions with Answers

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Professional Circuit Breaker FAQ Questions and Answers

Welcome to our comprehensive Trivia Quiz and interview preparation guide. Below you will find a curated list of popular Trivia Questions and Answers specifically for Circuit Breaker. Whether you are preparing for a technical interview or just testing your knowledge, these FAQ Questions will help you succeed.

What is a circuit breaker?

Circuit Breaker is a mechanical device designed to close or open contact members, thus closing or opening an electrical circuit under the normal or abnormal conditions. It serves as an automatic safety device that detects abnormal current conditions and interrupts the flow of electricity to prevent damage to the circuit and associated equipment.

How does a circuit breaker differ from a fuse?

Circuit breakers can be reset after they trip, while fuses must be replaced once they have blown.

What are the main components of a circuit breaker?

The main components of a circuit breaker include the contacts, operating mechanism, trip unit, and housing.

What is the purpose of the contacts in a circuit breaker?

The contacts in a circuit breaker are responsible for making or breaking the electrical circuit.

What are the different types of circuit breakers based on their operating mechanism?

Circuit breakers are available in different types, including thermal, magnetic, and thermal-magnetic and electronic circuit breakers

Can a circuit breaker be manually reset?

Yes, after a circuit breaker trips due to a fault, it can be manually reset by first moving it to the ‘off’ position and then back to the ‘on’ position.

How does a Circuit Breaker different from Switch?

Switch is just a device when can be able to open and close the circuit during normal operation. Whereas on the other hand circuit breaker has the ability to open and close the contacts during abnormal or fault conditions.

What is the difference between a single-pole and a double-pole circuit breaker?

A single-pole circuit breaker interrupts only one conductor, while a double-pole circuit breaker interrupts both conductors simultaneously.

How are circuit breakers rated?

Circuit breakers are rated based on their voltage, current capacity, interrupting capacity, and type of load they can handle.

What is the interrupting capacity of a circuit breaker?

The interrupting capacity of a circuit breaker is the maximum fault current that it can safely interrupt without sustaining damage.

What are the different types of circuit breaker trips?

Circuit breakers can trip due to overload, short circuit, or ground fault conditions.

What is a ground-fault circuit interrupter (GFCI)?

A ground-fault circuit interrupter is a type of circuit breaker that detects ground faults and quickly interrupts the circuit to prevent electric shock.

Where are GFCIs typically installed?

GFCIs are typically installed in areas where water and electricity are present, such as bathrooms, kitchens, and outdoor outlets.

What is an arc-fault circuit interrupter (AFCI)?

An arc-fault circuit interrupter is a type of circuit breaker that detects dangerous electrical arcs and interrupts the circuit to prevent fires.

How does an AFCI differ from a GFCI?

A GFCI detects ground faults, while an AFCI detects dangerous electrical arcs.

What is meant by making capacity of the circuit breaker?

The making capacity of the circuit breaker when closed on a short circuit is the peak value of the maximum current wave (including dc component) in the first cycle of the current after the circuit is closed by the circuit breaker.

Why current chopping is not common in oil circuit breakers?

Current chopping is not common in oil circuit breakers because in most of the oil circuit breakers the arc extinguishing power is proportional to the magnitude of current to be interrupted.

Name the materials used for the contacts of vacuum circuit breakers?

Copper-Bismuth, Copper-lead, Copper-tellurium, Silver-bismuth, Silver-lead and Silver-tellurium are some of the alloys employed as contact materials in the vacuum circuit breakers.

Why current chopping considered as serious drawback in a circuit breaker?

The current chopping is considered as serious drawback because it sets up high voltage transient across the breaker contacts.

How can circuit breakers contribute to electrical safety in buildings?

Circuit breakers help prevent electrical fires and electrocution by quickly interrupting the flow of current in the event of a fault or overload.