Generator Safety Tips
Last updated:
Fact-checked by Marcus Hayes, Master Electrician (License #CA-EL-89241), 15 years generator installation experience.
Portable generators cause over 70 carbon monoxide deaths per year in the United States. Almost every one is preventable. This guide covers the five critical safety rules every generator owner must follow, plus electrical, refueling, and weather safety. Written by a licensed master electrician.
Key Takeaways
- Place gas and propane generators at least 20 feet from any door, window, or vent — no exceptions.
- Never run a generator indoors, in a garage, or in any enclosed space — CO kills within minutes.
- Always use a battery-powered CO alarm inside your home, near sleeping areas.
- Never refuel a running or hot generator — let it cool for 15 minutes first.
- Use a transfer switch or interlock kit — never backfeed a panel through a wall outlet.
- Solar generators are the only type safe for indoor use — no CO, no emissions, no fuel.
The five critical generator safety rules
(1) Place the generator at least 20 feet from any building opening with exhaust pointed away. (2) Never
run a gas generator indoors or in a garage. (3) Use a battery-powered CO alarm inside the home. (4)
Never refuel a running or hot generator. (5) Use a transfer switch — never backfeed a panel. Following
these five rules prevents the vast majority of generator-related deaths and injuries.
Carbon Monoxide is the #1 Generator Killer
Carbon monoxide (CO) from portable generators kills over 70 Americans per year and sends thousands to the ER. CO is odorless, colorless, and lethal. Symptoms include headache, dizziness, nausea, and confusion — flu-like symptoms without a fever. If you experience these while a generator is running, get to fresh air immediately and call 911.
Electrical safety
Never connect a generator to your home panel without a transfer switch or interlock kit. Backfeeding
(plugging a generator into a wall outlet) energizes utility lines and can kill utility workers. Use
heavy-duty, outdoor-rated extension cords (12-gauge minimum for 20A circuits). Do not overload
extension cords — check the amp rating and do not exceed it. Keep cords dry and away from standing
water.
Refueling safety
Never refuel a running or hot generator. Shut off the generator and let it cool for at least 15
minutes before adding fuel. Gasoline spilled on a hot engine or muffler will ignite instantly. Keep
a Class B fire extinguisher nearby. Store fuel in approved containers away from the generator and
living areas. Never smoke while refueling.
Weather safety
Do not run a gas generator in rain or wet conditions without a purpose-built generator tent (GenTent,
IGAN). Never use a tarp — it traps exhaust and creates a CO hazard. Do not touch a generator with wet
hands or while standing in water. Solar generators should be kept dry — most are not weatherproof.
In winter, keep the generator clear of snow and ice accumulation.
Frequently Asked Questions
How far should a generator be from the house?
A portable generator must be placed at least 20 feet from any door, window, or vent, with the exhaust pointed away from the building. Standby generators must be placed 18 inches to 5 feet from the house wall per manufacturer specifications. Solar generators (battery power stations) produce no emissions and can be used indoors with no distance requirement.
Can I run a generator in my garage?
No. Never run a gas or propane generator in a garage, even with the door open. Carbon monoxide builds up quickly in enclosed spaces and can kill within minutes. Generators must be placed outdoors at least 20 feet from any building opening. Solar generators are the only type safe for indoor and garage use.
Do I need a CO alarm if I have a generator?
Yes. If you own or operate a gas or propane generator, you must have a battery-powered CO alarm inside your home, near sleeping areas. Even if your generator has a built-in CO shutoff sensor, a secondary indoor CO alarm is critical because CO can enter through doors, windows, and vents from a generator placed too close to the house.
Can I refuel a running generator?
No. Never refuel a running or hot generator. Gasoline spilled on a hot engine will ignite immediately. Always shut off the generator, let it cool for at least 15 minutes, then refuel. Keep a fire extinguisher rated for flammable liquids (Class B) nearby.
What is the 20-foot rule for generators?
The 20-foot rule states that a portable generator must be placed at least 20 feet from any door, window, or vent of a building, with the exhaust pointed away from the building. This distance prevents carbon monoxide from entering the home. The rule applies to all gas and propane generators regardless of wattage. It is based on CPSC data showing that most CO deaths occur when generators are placed too close to the house.
Are solar generators safer than gas generators?
Yes. Solar generators (battery power stations) produce no carbon monoxide, no emissions, and no fire risk from flammable fuel. They can be used indoors, in garages, and in enclosed spaces. They have no hot surfaces, no moving parts, and no refueling risk. The only safety consideration is keeping them dry — most are not weatherproof and should not be used in rain.