Correct Answer - Option 1 :
Short circuit
Concept:
Circuit Breakers are quite unique devices in the sense that they are mechanical devices connected to electrical system. Since the time when first electrical systems were utilized, there is always a need for a mechanism or a device that can initiate and interrupt the flow of electric current.
Circuit Breakers are mechanical switching devices that can make, or break a circuit either manually or automatically under normal and abnormal circuit conditions.
Explanation:
There are three reasons because of the circuit breakers cut off the main supply.
- Electrical circuit overload
- Short circuit fault
- Ground fault
Electrical circuit overload:
- An electrical circuit overload occurs when the current passing through the circuit breaker exceeds its rated value for a duration longer than normal conditions.
- Because of over-current, circuit breaker trips the circuit immediately.
- For instance, if a 15-amp breaker experiences a current of 25-amps, it will trip almost instantly.
Short circuit fault:
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The Short circuit fault occurs when there is contact between a neutral and live conductor, thus drawing a current that may be significantly higher than the rated value.
- In case of a short circuit fault, the magnetic tripping mechanism will be activated in order to clear the fault as soon as possible.
- The high fault current can start a fire or damage the equipment in a matter of minutes.
- If there is more than one live conductor in a circuit, a short circuit can occur when there is contact between different phases.
- A short circuit is common but potentially dangerous.
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The circuit breaker cut off the main supply immediately to prevent an electrical fire.
Ground fault:
- Ground fault occurs when a live conductor touches a conductive surface that is not a part of the circuit.
- The current is extremely high, the fault must be cleared immediately by the magnetic tripping mechanism in the circuit breaker.
