Automatic Transfer Switch

An automatic transfer switch is a device that senses the loss of the normal electricity supply to a building or piece of equipment and switches the load over to a backup source, typically a standby generator, without a person having to act. Once utility power returns and stabilizes, the switch transfers the load back to the normal source and signals the generator to shut down. They are standard equipment wherever a continuous supply matters, such as hospitals, data centers and emergency services buildings, ranging from small units for a single building to large units integrated into industrial switchgear.