Portable generator safety: the 20-foot rule and a pre-outage plan
Place a portable generator outdoors at least 20 feet from homes and buildings, point exhaust away from openings, and plan loads and connections before the power fails.
Portable generators create carbon-monoxide, fire, shock, and backfeed hazards. CPSC's 2026 storm guidance says to operate them outdoors only, at least 20 feet from homes and buildings, with exhaust directed away from windows, doors, and vents. A porch, carport, shed, crawlspace, basement, or garage does not meet that boundary, even with a door open.
The worst decisions often happen during a dark, stressful outage. Make the plan while the lights are on: what truly needs power, where the generator can sit, how cords will stay dry and protected, and when unsafe weather or clearance means the equipment stays off. A generator should never be connected to home wiring except through equipment installed for that purpose by a qualified electrician.
The short answer
Run a portable generator outdoors only, at least 20 feet from homes and buildings with exhaust aimed away from openings. A porch, carport, shed, basement, crawlspace, or open garage is not a safe substitute.
Decide what is truly essential
List the appliances and devices the household needs during an outage, including medical equipment. Check running and starting wattage in manuals or labels; do not assume a generator can handle every circuit at once.
Measure the 20-foot boundary in advance
Identify a level outdoor location at least 20 feet from homes and buildings, direct exhaust away from every nearby opening, and keep the unit away from floodwater. Plan weather protection only if it does not enclose the generator or restrict exhaust, and follow the manufacturer’s instructions.
Use suitable cords and connections
Use outdoor-rated cords in good condition and keep connections dry. For a transfer switch, inlet, or panel connection, hire a qualified electrician and use equipment designed for your generator and electrical system.
Start and operate with the manual
Follow the manual’s startup, load, grounding, and maintenance requirements. Keep children and pets away. Never operate equipment that is damaged, wet, overheating, or producing an unfamiliar warning.
Shut down safely
Disconnect loads as directed, turn the unit off, let it cool, then refuel only if needed. When utility power returns, use the installed transfer equipment properly rather than reconnecting household circuits by guesswork.
Put the guide to work
Field notes
- Location is non-negotiable
- CPSC says to operate the generator outdoors at least 20 feet from homes and buildings, with exhaust directed away from windows, doors, and vents. Follow any additional manufacturer requirements; a porch, carport, shed, or garage with the door open is still not a safe operating location.
- CO alarms stay active
- Working carbon-monoxide alarms inside the home are a second line of warning, not permission to place a generator closer. If a CO alarm sounds, get outside and call emergency services.
- Never backfeed
- Do not plug a generator into a wall outlet or use an improvised double-male cord. Backfeeding can energize utility lines and harm workers, neighbors, and the home’s electrical system.
- Fuel only when cool
- Turn the generator off, allow it to cool, and refuel outdoors. Store fuel in an approved container away from living areas and ignition sources, following local fire guidance and the manual.
- Make an outage load card
- Before an outage, write the exact essential loads, their running and starting requirements from labels or manuals, and the order in which they will be connected. Include what stays off. This is safer than deciding at night that a refrigerator, space heater, pump, and whole house can all run together.
- Draw the no-go boundary
- Mark the planned outdoor operating spot and the nearby doors, windows, vents, garages, and flood-prone areas. If weather, wind, standing water, or available clearance makes that spot unsafe, the answer is not to move the generator indoors—it is to leave it off and use the household outage plan.
Make the next step useful
Put this guide on your home plan
Know when to call a professional. Stop if work involves active gas leaks, damaged service wiring, structural movement, unsafe heights, suspected contamination, or a problem you cannot confidently isolate.
Editorial review and sources
Reviewed by: Smart Homeowners Editorial Desk
Last reviewed: September 4, 2026
Original Smart Homeowners editorial; not adapted from a third-party article.
