Generator questions
Generator interlock or transfer switch: which do you need?
Both let a portable generator power your home without feeding electricity back onto the utility line. An interlock is a listed device on your existing panel that keeps the main breaker and the generator breaker from being on at the same time. A transfer switch is a separate device that moves a set of circuits from utility power to generator power.
How they compare
| Panel interlock kit | Manual transfer switch | |
|---|---|---|
| Where it goes | On your existing panel | A separate device beside the panel |
| Which circuits run | Any circuit in the panel, chosen at the time | The circuits wired to it ahead of time |
| Switching over | By hand, at the panel | By hand, at the switch |
| Generator connection | Through an outdoor power inlet | Through an outdoor power inlet |
An interlock may suit you if
- You have a portable generator and room in your panel
- You’d like to choose which circuits to run during each outage
A transfer switch may suit you if
- You’d like a fixed set of circuits ready to switch over
- Your panel can’t take an interlock kit
Never backfeed
Plugging a generator into an outlet without one of these devices can send power onto the utility line, which endangers line workers and can damage your home.
Not sure which your panel can take?
We’ll look at it and tell you. See what’s included in a generator hookup, or request a project estimate.