I spent 19 years around jet fuel and hydrazine as a hazmat responder, and I’ll tell you what the Air Force drilled into me: the dangerous stuff is never the exotic stuff — it’s the routine step somebody skipped. Generator accidents follow the same pattern. Here’s every rule that matters, and why.

Carbon Monoxide: The One That Kills

CO is odorless, colorless, and a portable generator produces a staggering amount of it. The rules are absolute: outdoors only, 20+ feet from the house, exhaust pointed away from doors and windows. Not the garage with the door open. Not the covered porch. Every year people die from “just for a little while” — my full guide covers placement, wind, and the mistakes that show up in the news every storm season: Generator Carbon Monoxide Safety.

Newer units have built-in CO shutoff sensors, and they trip for good reasons — and occasionally bad ones. If yours keeps shutting down with a flashing light, here’s how to tell a real CO event from a nuisance trip: Generator CO Sensor Keeps Shutting It Off.

Refueling: Shut It Down, Let It Cool

Gasoline vapor plus a hot muffler is a flash fire waiting for permission. Never refuel a running or hot generator — shut it down, give it several minutes, then open the cap. Plan your fuel stops around it. If you’re running long through an outage, the shutdown-cool-refuel cycle is part of the routine, covered here: How Long Can You Run a Generator Continuously.

Backfeed: Never Plug Into a Wall Outlet

Plugging a generator into a wall outlet with a homemade double-male cord energizes your house wiring backwards — and energizes the utility line outside, where it can kill a lineman working to restore your power. It’s illegal, and it’s the single most dangerous shortcut in this hobby. The right ways to tie into the house are a transfer switch or an interlock kit, and I compare them here: How to Connect a Portable Generator to Your House.

Cords: Size Them or Cook Them

An undersized extension cord under generator load gets hot, drops voltage, and slowly cooks whatever’s plugged into it. Gauge and length both matter — a 16-gauge cord that’s fine for a lamp will starve a space heater at 100 feet. The sizing chart is here: What Size Extension Cord for a Generator.

Weather, Grounding, and Placement

Keep the unit on dry, level ground under a canopy or generator tent if it’s raining — water and outlets don’t negotiate. For most portable use with extension cords, the frame serves as the ground and no rod is required; check your manual, because a few configurations (and most transfer-switch installs) do call for a ground rod. And give the machine air on every side — cooling matters, especially on long runs, as covered in Generator Overheating and Shutting Off.

The Quiet Alternative

Worth saying: for daily supplemental power, a solar battery station produces zero CO and can sit inside the house. I run one every day — here’s my real setup with the wattage numbers: Running a 12,000 BTU Portable AC on Solar.

Generator acting up right now?Run the Fix My Generator diagnostic — pick your symptom and I’ll walk you straight to the fix. →