Automatic Transfer Switches

Choosing the right amperage

Transfer switches are specified by amperage and by how many circuits they carry. A 50-amp, 10-circuit switch is sized for essential-circuit backup: furnace, well pump, refrigeration, a few lighting and outlet circuits, and the sump. You decide in advance which circuits matter and the electrician wires those to the switch. A 100-amp, 14-circuit unit widens that list and suits most homes that want comfort as well as safety during an outage.

Service-entrance rated switches in the 100A, 150A and 200A sizes work differently. Rather than backing up a selected list, they sit at the service entrance and transfer the entire panel, which means every circuit in the house is available. Whole-house switches are the right answer when the load calculation supports it and when you would rather not decide during a storm which half of the house stays dark.

Enclosures and installation

Every switch in this collection is NEMA 3R rated, meaning the enclosure is built for outdoor mounting and will shed rain, sleet and ice. Placement is usually beside the meter or the main panel, on the same wall run as the generator feed.

Transfer switch installation is licensed electrical work in every jurisdiction we ship to. The switch interrupts the connection between your home and the grid, and doing that incorrectly puts line workers at risk of backfeed. Have a licensed electrician size, permit and install the unit, and have the load calculation done before ordering so the amperage and circuit count match the panel you actually have.

Load management

Where the generator is smaller than the total connected load, a load management module lets a large intermittent load such as an air conditioner or an electric range share capacity with the rest of the house instead of forcing a larger generator. Load management modules are listed separately from transfer switches because they are a different device with a different job.