A transfer or throw switch, sometimes called a double throw switch, is an essential mechanism that shuts off power to the grid before backup power is used.

The transfer switch has an important job

The switch is typically used for generators rated at 5,000 watts or more. It connects the generator to your home’s main circuits to provide backup power during an outage. In other words, the transfer switch changes or transfers the power load from one source to another. It prevents power from backfeeding into the power grid and endangering utility workers and others.

The type of switch depends on the type of generator

A permanent standby generator has an internal switch that automatically transfers the source of power. Standby generators must be installed by licensed contractors, usually at the side of a home. Standby generators are called just that because they automatically turn on when the power goes out.

Not all permanently installed generators are standby versions. Some have manual transfer switches. Make sure your permanent generator and switch are installed to code and working properly.

Portable generators can also be connected to your home’s electrical service panel that is properly wired through a transfer switch. If you use a portable generator, never plug it into a wall outlet as this can cause backfeed.

Always use a generator safely

If you own a generator of any type, it is critically important that you have a working carbon monoxide detector. Generators are the single largest cause of serious injury and death following a major disaster that involves a prolonged loss of power.