A backup generator is a great tool and a serious hazard if used carelessly. Three rules prevent almost every generator tragedy: run it outdoors and far from the house, because carbon monoxide kills; never connect it to your home wiring without proper equipment, because backfeeding can electrocute people; and handle fuel carefully, because hot engines and gasoline do not mix. Here is what that means in practice.
Portable generators cause deaths every year, and the causes are predictable: carbon monoxide poisoning from running them in or near enclosed spaces, electrocution from improper connections to home wiring, and fires from careless refueling. The good news is that all three are preventable with habits that take seconds. Treat the rules below as non-negotiable rather than suggestions.
Outdoors only, and not just outside a door. Run it on dry ground at least 20 feet from the home, with the exhaust pointed away from doors, windows, and vents so fumes cannot drift back inside. Never run a generator in a garage, carport, shed, basement, or any enclosed or partly enclosed space, even with the door open, because carbon monoxide is invisible, odorless, and accumulates fast. As a second line of defense, keep battery-backed carbon monoxide alarms inside the home, especially near where people sleep.
Backfeeding means plugging a generator into a regular wall outlet to energize your home's circuits. It is one of the most dangerous things you can do with a generator. It can send power back onto utility lines and electrocute line workers or neighbors, it can damage your home and the generator, and it bypasses your home's safety devices. The safe ways to power your house are to run appliances directly from the generator using heavy-duty, outdoor-rated extension cords, or to have a licensed electrician install a transfer switch or interlock kit that isolates your home from the grid before generator power is applied.
Fuel causes the fires. Always turn the generator off and let it cool before refueling, because gasoline spilled onto a hot engine or exhaust can ignite. Store fuel in approved, labeled containers away from living spaces and any ignition source such as a water heater pilot light, and keep only what you can rotate, using a stabilizer for longer storage. Do not overfill the tank, and clean up spills before starting.
Keep the generator dry. Running it in rain or standing water risks electrocution, so use it under an open, well-ventilated canopy made for the purpose, never inside a closed structure. Do not exceed its rated wattage either, since overloading can damage the generator and what is plugged into it. Add up the running watts of your loads and stay comfortably under the limit, the same sizing logic from our sizing guide.
Carbon monoxide poisoning can feel like the flu: headache, dizziness, weakness, nausea, shortness of breath, and confusion. If you or anyone nearby feels these symptoms while a generator is running, get to fresh air immediately and call emergency services. Do not go back inside a space you suspect is contaminated. When in doubt, treat it as an emergency.
No. A generator must run outdoors only, well away from the house, because carbon monoxide builds to deadly levels in enclosed and partly enclosed spaces, including garages and carports, even with a door or window open.
Place it outdoors at least 20 feet from the home, with the exhaust pointed away from any doors, windows, and vents. Install battery-backed carbon monoxide alarms inside as a second line of defense.
Backfeeding is plugging a generator into a wall outlet to power your home's wiring. It is extremely dangerous: it can electrocute utility workers and neighbors and damage your home. Use a transfer switch or interlock installed by a licensed electrician, or run appliances on rated extension cords instead.
Never. Turn the generator off and let it cool first, because spilled fuel on a hot engine can ignite. Store fuel in approved containers away from living spaces and any ignition source.
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