A manual transfer switch is installed to manually connect the generator to the house and is used in applications where power loss is rare. An automatic transfer switch (ATS) is installed to automatically connect the generator to the house and is used in applications where power loss is expected.
Automatic transfer switches rely on the backup generator to start the transfer from utility power to generator power. This is achieved through a series of sensors that communicate with the device.
A manual transfer switch relies on the operator to start the transfer from utility power to generator power. This is achieved by manually starting the transfer process.