Top 3 causes behind a circuit breaker trip | MCB Trip

Circuit breakers are employed to automatically switch off a circuit or a load whenever any abnormalities in current flow are detected. This functionality of the circuit breakers is known as ‘Trip’. By doing so, circuit breakers are preventing fire or other damages caused to the circuit. Here are the major reasons behind your circuit breaker trip. In this article, we discuss domestic circuit breakers such as an MCB, MCCB and residual current devices (RCD, RCCB, RCBO).

Why did your circuit breaker trip?

Circuit breakers have replaced the traditional fuses due to its re-usability. At least one of the following situations can trip your circuit breaker.

Overload

This is one of the prominent reason behind a circuit breaker trip. An overload is a situation at which a device or a circuit draws more current than the value it can safely handle. One such example of an overload is plugging in many appliances to single power socket such that the loads all together draws more current than the socket can deliver.

circuit breaker trip due to 
overload

In the above case, if the load current is higher than the rated current of the MCB (Miniature circuit breaker) for certain period of time, the MCB trips.

Short-Circuit

Short circuits are more dangerous than overloads. These are the situations in which live conductor comes in direct contact with the neutral conductor (Direct contact of positive and negative in case of DC) resulting in a current flow several times the normal value.

Short circuit

This could be the result of wrong wiring or damages inside the appliance plugged. During short circuits the circuit breakers or MCB trips instantaneously.

Learn the key differences between a Short circuit and an overload here.

Ground Fault or Earth Fault

A ground fault or an earth fault is a situation when a live conductor comes in direct contact with the ground or the earth conductor. This can cause circuit breaker trip if the fault current is considerably high. Residual current devices (Ground fault circuit interrupters, RCD, RCBO & RCCB) can offer better protection against earth faults.

The cause of a ground fault needs to be analyzed properly and rectified. Otherwise, it may result in electrocution and can be fatal.

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