Generator Safety Table
| Rule | Why it exists |
|---|---|
| Outdoors, 20 ft (6 m) from windows/doors/vents | Generator exhaust holds hundreds of times a car's CO - placement plus wind direction is the only defense |
| Never indoors - garages included, doors open | CO pools and migrates into living space despite ventilation; sleeping victims never wake |
| Never backfeed - transfer switch only | Backfeeding energizes "dead" lines and can electrocute the line crew repairing them; illegal in most jurisdictions |
| Refuel outdoors, engine cool 15+ min | Hot engines ignite gasoline vapor on contact - fuel fires are the #2 generator injury after CO |
| Rain: open-sided canopy only, dry hands | Attached carports and enclosed porches trap exhaust; water plus live panels adds shock risk |
| Battery CO alarms on every sleeping level | The house cannot smell CO - the alarm is the only sensor you have; sound means out immediately |
Every storm-season blackout brings the same avoidable deaths: portable generators kill more people after hurricanes and ice storms through carbon monoxide than through any other route, because the machine is treated like an appliance instead of a small engine. A generator's exhaust can hold carbon monoxide at levels hundreds of times higher than a car's - and CO is odorless, colorless, and invisible, so the only working defense is placement plus an alarm, not your senses.
Bottom line: run it outdoors, at least 20 feet (6 meters) from any window, door, or vent, with the exhaust pointing away from the house; never inside - including the garage with the door open; never wired into the house except through a transfer switch; refuel only outdoors after the engine cools; and keep battery-powered CO alarms inside on every sleeping level. Every rule below is the fix for a specific, repeating death.
The honest part: the 20-foot number is a minimum, not a safe distance badge - a generator hard against the far side of its own fence can still feed CO through a neighbor's window or your own vent intake. Placement means distance AND direction, and the direction rule is the one people forget.
How to use
- Pick the spot before the storm: outdoor ground at least 20 feet from every window, door, and intake vent, exhaust pointed away from the house and the neighbor's, under an open-sided canopy rather than a porch.
- Wire it right: plug appliances directly into the generator's outlets, or have an electrician install a transfer switch - never backfeed through a dryer outlet or into the wall, and never plug the generator into a wall outlet.
- Fuel it safely: shut the engine down and let it cool 15+ minutes before refueling; store gasoline outside living space in an approved can; run the machine dry or with stabilized fuel between seasons so the carburetor starts on demand.
Frequently asked questions
Can I run a generator in my garage with the door open?
No. This is one of the most common fatal setups: CO accumulates in the garage and migrates into living space even with the door wide open, because the exhaust keeps pumping while the air exchange is far slower than people assume. Carbon monoxide from a nearby garage has killed people asleep in bedrooms two floors up. The only safe location is fully outdoors, 20 feet from any opening.
Why is backfeeding the house with a generator illegal and deadly?
Backfeeding - wiring generator power into the house through a dryer or range outlet - energizes the home's wiring without isolating it from the grid. Line workers repairing what they believe is a dead line can be electrocuted by your generator, which is why it is illegal in most jurisdictions; inside your own home it can also fry everything when utility power returns, and bypasses the breaker protection a transfer switch provides. A transfer switch is a few hundred dollars; the alternative risks a life.
Can a generator run in the rain?
Only under a purpose-built open-sided canopy or generator tent - never in a garage, carport attached to the house, or enclosed porch. Water itself is a secondary risk: operate with dry hands, keep the unit on a dry surface, and connect cords before starting. Third-party manufacturer canopies exist for exactly this; a tarp rigged too close to the hot exhaust is not one of them.
How long should a generator cool before refueling?
At least 15 minutes, until the engine and muffler are cool to a careful touch. A running or recently-run engine is hot enough to ignite gasoline vapor the instant you pour - fuel fires around generators are the second most common generator injury after CO poisoning. Shut it down, cool it, refuel outdoors with a funnel, and wipe spills before restarting.
Where should carbon monoxide alarms go when running a generator?
Battery-powered (or battery-backup) CO alarms inside the house, on every level and outside sleeping areas - because the generator's CO enters the house silently, the alarm is the only sensor you have. If an alarm sounds, get everyone outside to fresh air immediately and call for help from outdoors; do not open windows and wait inside. Test the alarms before storm season, not during the outage.
Are inverter generators safe to use indoors?
No fuel-burning generator is indoor-safe - inverter models run quieter and throttle efficiently, but they burn gasoline and exhaust carbon monoxide exactly like any other. The indoor-safe category is battery power stations: large lithium packs (often marketed as solar generators with panel charging) produce zero exhaust and can run indoors. If your blackout plan depends on indoor power, a battery station sized for the fridge and one lamp beats any generator placed badly.