What is a vacuum circuit breaker, how does it work, and in what conditions should use it?

What is a vacuum circuit breaker?

A vacuum circuit breaker, often known as a VCB, is a kind of electrical switch that functions in a condition that is devoid of air. Its purpose is to protect electrical systems and equipment from overloads & short circuits, respectively.

Function of VCB

The VCB is able to perform its function by cutting off the flow of current whenever it reaches a threshold that has been previously established. This keeps the equipment from being damaged.

It is known that vacuum has a high dielectric strength and is capable of withstanding high voltage levels is the primary reason why it is used as an interrupting medium in VCBs. In addition, since the vacuum atmosphere is devoid of air and other gases, there is no potential of arcing, which is a phenomenon that, if it occurs, may cause damage to the switch contacts & other parts of equipment.

Application of VCB

In high voltage power systems, such as those found in power plants, distribution networks, and substations, VCBs are a frequent component that can be identified. They have been preferred over various types of circuit breakers due to the lower amount of maintenance that is required for them and the longer lifetime that they possess. In addition, VCBs have a quicker reaction time than various types of circuit breakers, which allows them to stop large currents in a timelier manner.


In simple terms, a vacuum circuit breaker is an electrical switch that functions in an atmosphere that is devoid of air. Its purpose is to protect electrical components and systems from overloads and short circuits. Because of its high dielectric strength, capacity to resist high voltage levels, and quick reaction time, it is favoured over other kinds of circuit breakers and is used in high voltage power systems. This is owing to the fact that it is utilised in these systems.