A transfer switch is an electrical switch that switches a load between two sources. Some transfer switches are manual, in that an operator effects the transfer by throwing a switch, while others are automatic and trigger when they sense one of the sources has lost or gained power.
An Automatic Transfer Switch (ATS) is often installed where a backup generator is located, so that the generator may provide temporary electrical power if the utility source fails.
For example, in a home equipped with a backup generator and an ATS, when an electric utility outage occurs, the ATS will tell the backup generator to start. Once the ATS sees that the generator is ready to provide electric power, the ATS breaks the home’s connection to the electric utility and connects the generator to the home’s main electrical panel. The generator supplies power to the home’s electric load, but is not connected to the electric utility lines. It is necessary to isolate the generator from the distribution system to protect the generator from overload in powering loads in the house and for safety, as utility workers expect the lines to be dead.
When utility power returns, the transfer switch will transfer the house back to utility power and command the generator to turn off.
In most cases the Automatic transfer switch is built internally to the generator. For instances where the distance between the distribution board and the generator is prohibitive we offer a loose standing transfer switch option.