Updated: Aug 30, 2019
By Paul Hope
Last updated: July 11, 2019
In the aftermath of a storm, a generator is an invaluable piece of equipment that can, at the very least, help your life begin to feel normal again.
But because you probably rarely rely on a generator, it’s easy to overlook the basic safety measures that should be routine with such equipment. It’s also easy to get preoccupied by the cleanup work that lies ahead, so you may even be tempted to run a generator in a living space if most of your house is severely water damaged and cannot be saved.
That is never an option.
Portable generators can produce high levels of carbon monoxide, a deadly, odorless, and colorless gas. Generator misuse leads to carbon monoxide deaths, injuries from close calls, and burns—all of which happen too often during power outages and storms.
Running a generator improperly can kill you in as little as 5 minutes if the concentration of carbon monoxide is high enough. From 2005 to 2017 more than 900 people died of carbon monoxide (CO) poisoning while using portable generators, according to data from the Consumer Product Safety Commission (CPSC).
To reduce the risk of carbon monoxide poisoning, some new portable generators feature a built-in sensor that triggers an automatic shutoff if CO builds up to dangerous levels in an enclosed space, and some also have engines that emit less CO in the first place. Recent test data from CR shows that these safety features will likely save lives.
Consumer Reports now only recommends portable generators that pass our CO Safety Technology test.
Whether you buy a new generator that implements these new safety standards, or you're running an older model without an auto shutoff, we still advise consumers to follow the safety advice that follows.
How to Operate a Generator Safely
Never run a generator in an enclosed space or indoors. Most generator-related injuries and deaths involve CO poisoning from generators used indoors or in partially enclosed spaces. That includes the basement or garage, spaces that can capture deadly levels of carbon monoxide. Always place the generator at least 20 feet from the house with the engine exhaust directed away from windows and doors.
And if you’re using a generator to keep the lights on during a cleanup effort, “use a working, battery-operated carbon monoxide detector at the same time,” says Ken Boyce, principal designated engineer manager at UL. A carbon monoxide alarm provides one more layer of defense against making an innocent but potentially deadly mistake.
Don’t run a portable generator in the rain. You can buy tents for generators—that keep them shielded but still well-ventilated—online and at home centers and hardware stores.
Before refueling, turn off a gas-powered generator and let it cool. Gasoline spilled on hot engine parts can ignite. Allowing the engine to cool also reduces the risks of burns while refueling.
Stock up on extra gasoline and store it properly. When you think you’ll need to use the generator for an extended time, you’ll want extra fuel on hand. Just be sure to store gas only in an ANSI-approved container in a cool, well-ventilated place.
Adding stabilizer to the gas in the can will help it last longer, but don’t store gasoline near any potential sources of heat or fire, or inside the house.
Avoid electrical hazards. If you don’t yet have a transfer switch, you can use the outlets on the generator—providing you follow certain precautions: It’s best to plug in appliances directly to the generator. If you must use an extension cord, it should be a heavy-duty one for outdoor use, rated (in watts or amps) at least equal to the sum of the connected appliance loads. First check that the entire cord is free of cuts and that the plug has all three prongs, critical to protect against a shock if water has collected inside the equipment.
Install a transfer switch before the next storm. This critical connection will cost from $500 to $900 with labor for a 5,000-rated-watt or larger generator. A transfer switch connects the generator to your circuit panel and lets you power hardwired appliances while avoiding the glaring safety risk of using extension cords. Most transfer switches also help you avoid overload by displaying wattage usage levels.
Don’t attempt to backfeed your house. Backfeeding means trying to power your home’s wiring by plugging the generator into a wall outlet. This reckless and dangerous practice presents an electrocution risk to utility workers and neighbors served by the same utility transformer. It also bypasses some of the built-in household circuit protection devices, so you could end up frying some of your electronics or starting an electrical fire.