Portable Generator Safety for NYC Homes: Backfeeding, Carbon Monoxide, and the Right Way to Wire In

When a summer storm or a heat wave knocks out power in New York City, a portable generator can keep your fridge cold and a few lights on. Used the wrong way, that same machine can kill you, your neighbors, or a Con Edison lineworker. The two deadliest mistakes are also the most common — and both are avoidable. Here's what a licensed electrician wants every NYC homeowner and small business owner to know before the next outage.

Never plug a generator into a wall outlet (backfeeding)

"Backfeeding" means running a cord from your generator into a regular wall outlet to power your house. People do it because it seems quick. It is one of the most dangerous things you can do with electricity.

When you backfeed, power flows backward through your panel and out to the utility transformer on the street — which runs in reverse and steps your generator's output up to roughly 7,200 volts or more on the neighborhood lines. A Con Ed crew working to restore power reasonably assumes those lines are dead. Your generator can electrocute them. This is exactly the hazard OSHA flags when it warns about voltage backfeed onto de-energized lines.

The double-ended cord used to do this is known in the trade as a "suicide cord" — both ends have male prongs, so the moment one end is live, the exposed prongs on the other are lethal to touch. Backfeeding can also overload and overheat your home's wiring and start a fire. In NYC's older row houses with shared walls, that fire is not just your problem.

Carbon monoxide kills faster in dense housing

The Consumer Product Safety Commission reports that, on average, close to 100 people die every year in the U.S. from carbon monoxide poisoning tied to portable generators. CO is invisible and odorless, and the CPSC is blunt about it: running a generator in an enclosed space can kill you in minutes.

Their rules are simple and non-negotiable:

• Never run a generator indoors, in a garage, basement, crawlspace, shed, or any enclosed space — opening a window or door does not provide enough ventilation.
• Run it outside only, at least 20 feet from the house, with the exhaust pointed away from doors, windows, and vents.
• Install battery-backed CO alarms on every level of your home.

This matters more in New York than almost anywhere. On a Brooklyn or Queens block, "outside" often means a narrow side alley, a small backyard hemmed in by fences, or an airshaft between buildings. Exhaust that would dissipate in an open suburban yard can pool against a shared wall and seep through a neighbor's window. When you have to place a generator, get it as far from any structure — yours and the one next door — as your lot allows.

The right way: a transfer switch or interlock

The safe, legal way to connect a generator to your home's circuits is through equipment that makes it physically impossible to be on utility power and generator power at the same time. Two options:

• A manual transfer switch — a small subpanel that feeds a chosen set of circuits (furnace, fridge, a few lights). You plug the generator into an outdoor inlet and flip those circuits over. It cannot backfeed the grid.
• A generator interlock kit — a mechanical plate on your main panel that won't let the generator breaker and the main breaker be on together. It's cheaper, but it's panel-specific: not every panel has a listed kit, and an electrician has to confirm yours does.

Either way, the National Electrical Code requires the generator to connect through listed transfer equipment, with the neutral-to-ground bonding handled correctly so protective devices work as intended. Get that wrong and you reintroduce the shock and fire risks you were trying to avoid.

In New York City, this is not DIY work. Installing a transfer switch or interlock requires a permit filed through DOB NOW by a NYC Licensed Master Electrician, and the work has to be done by a licensed electrician. That's the law — and it's also what stands between you and a house fire or an electrocuted utility worker. If your panel is old or full, you may need panel work before a transfer setup can be added safely.

Cords, GFCI, and grounding

Even with everything wired right, the basics still matter. Use only heavy-gauge outdoor-rated cords sized for the load and free of cuts or cracks. For any cord-and-plug use, 120-volt outlets should be GFCI-protected — the same protection OSHA requires on jobsites — and never run cords under rugs or through standing water. Follow your generator's grounding instructions; don't improvise.

Storm season is the wrong time to discover your setup is unsafe. If you're not sure how your generator is connected — or you're eyeing a "quick" cord solution — have it looked at first. We handle transfer switch and interlock installs and electrical repairs & inspections across all five boroughs, permitted and to code. Reach out before the next outage, not during it.