A Vacuum Circuit Breaker (VCB) is an electrical device used to protect and control electrical circuits by interrupting the flow of current in the event of a fault. It operates by creating a vacuum environment in which electrical contacts are housed. When a fault occurs, the contacts separate, and the resulting arc is quickly extinguished due to the vacuum, preventing damage to the equipment. VCBs are known for their reliability, low maintenance, and compact size, making them ideal for medium-voltage applications in substations and industrial settings.