Portable generator: how to use it safely during an outage

Backup power helps only when the exhaust stays outside.

The answer in 2 lines. A fuel-powered portable generator produces carbon monoxide, an invisible, odorless gas that can kill. Run it outdoors, more than 20 feet from windows, doors and vents, with the exhaust facing away from homes. Never use it in a garage, basement, shed or enclosed porch, even with doors open. Plug appliances directly into it or use suitable outdoor extension cords. Never plug a generator into a wall outlet. Connecting it to house wiring requires a qualified electrician and appropriate transfer equipment. If a carbon monoxide alarm sounds or anyone develops symptoms, get everyone outside immediately and call 911.

The first 3 steps

Choose a safe outdoor location before starting the engine. Consider your neighbors' windows and vents as well as your own.
Check the operating instructions, generator capacity and extension cords. Connect only essential appliances within the equipment's ratings.
Check that your home's carbon monoxide alarms work. Before refueling, shut the generator off and let the engine cool.

Stop: danger

Headache, dizziness, weakness, nausea or confusion: get everyone into fresh air immediately and call 911. Do not delay evacuation to switch off the generator or open windows.
A carbon monoxide alarm sounds: leave immediately and call 911 from outside. Do not return until emergency responders say it is safe.
A generator connected to a wall outlet: do not use that setup. It can send electricity back onto utility lines and electrocute workers or neighbors.

Where it can safely run

Outside does not automatically mean safe. A generator against the house, beneath a window or inside a partly enclosed space can send exhaust indoors. Never operate it in a garage, crawl space, basement or shed. An open garage door does not provide enough protection.

Use the CDC's carbon monoxide prevention guidance to check placement: outdoors, more than 20 feet from windows, doors and vents. Point exhaust away from occupied buildings. If your property cannot provide a safe location, do not run the generator there.

Keep the equipment dry without enclosing it. Follow its operating instructions for a suitable open shelter; moving it into the garage during rain creates a potentially deadly hazard.

What not to do

Testing the engine indoors, even briefly.
Using a cord with damaged insulation, missing grounding prongs or an inadequate rating.
Connecting the generator to a household outlet with a cord that has exposed male plugs at both ends.
Adding fuel while the engine is running or hot.
Assuming an automatic carbon monoxide shutoff makes indoor use safe.

Connect appliances without backfeeding

For individual appliances, use the generator's outlets or heavy-duty outdoor extension cords rated for the connected load. Inspect the entire cord and protect it from being pinched in a doorway. Keep hands and connections dry.

Check both running and starting requirements: appliances with motors can need additional power when starting. Do not exceed the generator's ratings. Follow the appliance instructions before powering sensitive electronics or medical equipment.

For a connection to house wiring, arrange a qualified electrician and properly rated transfer equipment that meets applicable codes. Turning off the main breaker is not a substitute for a proper installation. The Texas Department of Insurance setup guide explains the distinction between appliance connections and a professionally installed house connection.

Fuel, weather and local requirements

Let the engine cool before refueling: spilled gasoline can ignite on hot parts. Store fuel in appropriate, labeled safety containers outside living areas and away from ignition sources. Keep children and pets away from hot engine and exhaust components.

Read the CPSC portable generator safety alert before setup; use its electrical, fire and fuel sections as a checklist. Follow local permit, electrical and fuel-storage requirements. A portable generator does not create a nationwide exemption from those rules.

Good to know

Carbon monoxide symptoms can resemble the flu. Several people feeling ill together is a warning, but one person's symptoms are enough to act.
Battery-operated or battery-backup carbon monoxide alarms add protection; they do not replace safe generator placement.
For poisoning advice, the California Department of Public Health outage guidance lists Poison Control at 1-800-222-1222. For suspected generator exposure or an alarm, evacuate and call 911.

After a storm, a household plans to power its refrigerator. The only available spot is a narrow passage beside the neighbor's bedroom window. They decide not to start the generator there and arrange another safe place to stay. Having a generator does not make every property suitable for using one.

A made-up story, for illustration.

Bobby

Sources, verification, confidence

Verified on November 4, 2026, for the United States. Confidence: high for carbon monoxide prevention, electrical hazards and refueling precautions; medium for installation requirements, which depend on local codes and equipment. This guide addresses fuel-powered portable generators.