How to run a generator safely
Published October 3, 2026.
Built by Jeremy Panasuk.
The watt number and the placement rule answer different questions. A small load is not permission to run the engine in the garage.
What the agencies say, without blending the distances
CPSC's 2026 hurricane-season warning calls portable generators one of the leading causes of post-storm carbon monoxide deaths, and calls carbon monoxide a colorless, odorless gas that can kill within minutes. The operating rules in that release:
- Never use a portable generator inside homes, garages, basements, crawlspaces, sheds, or other enclosed areas, even if doors or windows are open.
- Operate generators outdoors only, at least 20 feet from homes and buildings, with exhaust directed away from windows, doors, and vents.
Ready.gov says the same distance in its own words: generators, camp stoves, or charcoal grills should always be used outdoors and at least 20 feet away from windows. Its generator list adds: at least 20 feet from windows, doors, and attached garages; keep the generator dry; connect appliances with heavy-duty extension cords; let it cool before refueling because fuel spilled on hot engine parts can ignite.
FEMA's generator graphic says only use it outside at least 20 feet from homes and garages, never plug it into a wall outlet or main electrical panel, and keep the exhaust pointed away from the home.
OSHA's portable-generator fact sheet says never use a generator indoors or in enclosed spaces such as garages, crawl spaces, and basements, and that open windows and doors may not prevent CO from building up. It also says make sure a generator has 3 to 4 feet of clear space on all sides and above it so it can ventilate, and do not place it outdoors where doors, windows, and vents could let CO into occupied rooms. That 3 to 4 feet is clearance around the machine. It is not a shorter substitute for CPSC's 20 feet from the house. Using the OSHA clearance as the distance to a bedroom window would weaken the CPSC rule. This page does not do that.
OSHA also says shut the generator down and let it cool before refueling, because gasoline can ignite on hot engine parts.
Worked example: a 4-cup coffee maker
The load is deliberately small. Honda lists a 4-cup coffee maker at 600 starting watts and 600 running watts.
- Running total = 600 W. Extra surge = 0, because start and run are the same number.
- Peak = 600 W. With 20% headroom, 720 W, rounded up to the next 500 W = 1,000 W recommended.
- Gasoline at 50% of that recommendation = 1,000 / 7,000 gallons per hour. A 4 gallon tank in the calculator lasts 28.0 hours. Propane at ×1.37 lasts 20.4 hours on the same 4 gallons.
A 1,000 W result is still an engine. CPSC's ban on garage use does not have a watt exception. The storm runbook turns a larger running load into cans and a printed CO line. This page is the rule those cans do not replace.
A common mistake
Reading OSHA's 3 to 4 feet of clear space and parking the generator three feet from a door. OSHA says not to place it where CO can enter through doors, windows, or vents. CPSC and Ready.gov state 20 feet from the house. The coffee maker's 600 W does not pull the set closer to the wall.
Limits, and when to call a pro
Connecting the set to house wiring, instead of plugging appliances in with a heavy-duty cord, needs a transfer switch installed by a licensed electrician and a permit where local code requires one. FEMA says never plug a generator into a wall outlet. That job is backup generator installation, not a longer extension cord.
If anyone feels dizzy, weak, or sick, CPSC's safety alerts say to get to fresh air immediately. This page is not medical advice.
Compiled with AI assistance from the sources below. Spot an error? Email [email protected].