Transfer switches are electrical switches that can move an electrical load from one source to another. Very commonly they are found with backup power generators. When the power goes out, the Automatic Transfer Switch (or ATS) goes on – moving the electrical load of a given building to the generator. An ATS will isolate the backup generator from the electric utility while it is on and providing temporary power. There are also manual transfer switches that rely on the operator to switch the load over. When the utility power returns, the ATS can recognize this and tell the generator to shut off and switch the load back onto the utility power. Some transfer switches allow for load shedding and prioritization of optional circuits. More complex switchgear allow soft loading – a technique that can reduce peak load demand from a utility.