What Is a Transfer Switch?
A transfer switch is an electrical device that connects a building's wiring to a selected power source. It lets a generator supply power to connected circuits during a utility outage. The switch separates the utility supply from the generator supply during the change between sources.
Quick Facts About Transfer Switch
- Category
- Power source control
- Used for
- Generator connections
- Common confusion
- Circuit breaker
- Often discussed with
- Generator Installation
Key Takeaways About Transfer Switch
- Manual and automatic models operate differently.
- Your switch may supply selected circuits or the whole panel.
- A circuit breaker isn't a transfer switch.
How Transfer Switch Works
A transfer switch moves its electrical contacts to change the source feeding connected circuits. Those contacts separate the supply paths during the change. The connected circuits receive power from the selected source.
Related glossary terms: Backfeeding, Electrical Panel, Electrical Load.
A manual switch relies on a person to change its position. An automatic transfer switch senses a loss of utility power and signals a compatible generator to start. It changes the connection when the generator is ready. When utility power returns, the automatic switch can change the connection back.
The switch may serve selected circuits or a whole electrical panel. That choice affects which lights and appliances receive generator power. The generator's capacity also affects what you can run during an outage.
From the GMB Electric team
When we plan a generator installation, we check which circuits you want to keep powered. We also review the panel and generator connection. That helps us match the switch arrangement to your home's electrical setup.
Transfer Switch in Practice: A Real-World Example
A homeowner wants the refrigerator and furnace to run during an outage. The generator installation includes a transfer switch connected to those circuits, while other circuits remain on the utility supply.
Related Services
Related Terms
Backfeeding
Backfeeding is the flow of electricity into a circuit or system from a source other than its usual supply.
Electrical Panel
An electrical panel is a metal enclosure that distributes electricity to circuits throughout a building.
Electrical Load
An electrical load is the demand placed on an electrical system by equipment that uses power.
Circuit Breaker
A circuit breaker is an electrical protection device that stops current when a circuit draws too much electricity.
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