GUIDE
Connecting a Generator to Your Home Safely
The wrong connection can hurt you, your neighbors and the line crews who restore your power. This guide explains the options and what to ask a professional.
Never backfeed
Plugging a generator into a wall outlet with a homemade cable sends power backward through your house wiring and out to the utility lines. That can electrocute line workers and damage your equipment. Never do it.
Three safe ways to use a generator
| Method | What it is | Good for |
|---|---|---|
| Extension cords | Heavy-duty outdoor cords from the generator to appliances | A few items, a short run, a refrigerator and lights |
| Transfer switch | A panel installed by an electrician that connects selected circuits to the generator and disconnects them from the grid | Powering hardwired items like a furnace or well pump |
| Interlock kit and inlet | A mechanical device on your main panel that keeps the grid and generator from being connected at once, with an outdoor inlet for a generator cord | A lower-cost way to power several circuits, installed by an electrician |
Consumer Reports notes that a transfer switch installed at your breaker box is needed to connect a large portable or inverter generator to hardwired appliances.
Extension cord rules
- Use cords rated for outdoor use and for the load. Check the amps and wire gauge on the label.
- Keep cords short, undamaged and out of water.
- Do not run cords through a door that has to stay shut. Use a safe entry point for the cords and keep the generator outside, far from windows, doors and vents.
Questions to ask your electrician
- Which method fits my panel and my local code?
- Do I need a permit and an inspection?
- Which circuits should the generator power, and what is their total load?
- What size generator do you recommend for that load?
- Where should the inlet or switch go, and where should the generator sit?
- What do you need to see on the generator, such as a bonded neutral or a particular outlet type?
After installation
- Test the system before storm season, with the generator running outside.
- Label your panel.
- Keep the generator's manual with it.
- Install battery-powered carbon monoxide alarms and test them.
Sources
- CPSC Carbon Monoxide Information Center: https://www.cpsc.gov/Safety-Education/Safety-Education-Centers/Carbon-Monoxide-Information-Center
- CPSC, portable generator safety alert (PDF): https://www.cpsc.gov/s3fs-public/5123_SafetyAlert_PortableGenerators_102021.pdf
- Consumer Reports, generator sizing and transfer switches: https://www.consumerreports.org/home-garden/generators/how-to-choose-the-right-size-generator-a4942266454/
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