Circuit Breakers and Fuses – How They Work

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Generally, a solenoid is built into circuit breakers to reset the electrical current. It works on the principles of electromagnetic induction. A diode current is induced, which causes a resonance in the diaphragm. When the diaphragm is moved to reset the electrical current, a mechanical pressure is developed within the solenoid causing it to snap off the circuit breaker.

Why need Circuit Breakers and Fuses?

A circuit breaker is a specially operated electronic switch designed to prevent electric circuit from being damaged by excessive current from a short circuit or overload. It senses the difference between the voltage applied to it and the demand for electricity created by the circuit and shuts down the circuit to protect the circuit. Generally, it consists of two conductors that are connected in series. The load current passing through the circuit is cancelled by the breaker and the power supplied to the appliance or the device is restored.

However, circuit breakers need to have additional features to provide protection against shorts and overloads. Most common type of circuit breakers has a series of fuses fitted between terminals B and C. These fuses are open when one of the terminals is shorted or overloaded and are closed when the other terminal is restored to its original position. The combination of fuses provides excellent protection against shorts and overloads because there will be at least two of them for every possible scenario where a fuse will be tripped. This is especially true when the power coming into the appliance is much higher than the typical amount of fuses that are used. Additionally, the presence of at least two types of fuses will provide more safety against accidental interruption of your appliances.

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