Often used with a generator, this type of male-to-male extension cord can injure or kill you
Extension cords with two male ends are nicknamed "suicide cords" for a reason. Brush Wall Switch
Male-to-male extension cords, sometimes called suicide or widowmaker cords, are dangerous extension cords that can kill or injure you. People sometimes use them during a power outage to feed electricity from a generator directly into their home’s circuits to avoid the use of multiple extension cords. But their design makes male-to-male extension cords very unsafe, and you should never use one.
Unlike regular extension cords with one male (protruding plug) end and one female (receptacle) end, male-to-male extension cords have the male plug on both ends. When you plug one end of a male-to-male extension cord into a live electrical outlet, the other end is also live; it has electric current flowing from it.
“If I happen to hold the exposed metal end, there’s a shock hazard,” says Jeff Sargent, senior electrical specialist at the National Fire Protection Association in Quincy, Mass.
“Shock hazard” means you’re at risk of more than a slight buzz. The 120 volts that a three-pronged male-to-male extension cord carries is enough to kill you, Sargent says. Same for a four-pronged, 250-volt male-to-male extension cord, he adds. (We spotted online a four-pronged male-to-male extension cord “recommended” to connect a generator to a clothes dryer.)
People have been known to use a three-pronged male-to-male extension cord to attach a gasoline- or propane-powered portable generator to their home’s electric systems after a power outage. They plug one end of the cord into the generator and the other end into a receptacle in or on their house.
The idea is that power will backfeed—it will flow in the direction opposite to the way it usually goes. Instead of the electricity coming from municipal power lines through your home’s circuit breaker panel to outlets throughout the home, the electricity travels from the generator through the male-to-male extension cord and then through the receptacle it’s plugged into—and then into your home’s electrical system to power outlets.
In theory, using a male-to-male extension cord allows users to get electricity from their generators without using long extension cords or costly safety devices such as transfer switches (see more on those below). But the setup will never meet local electrical codes and poses a significant risk for injury, Sargent says.
We found male-to-male extension cords for sale through major online channels like Amazon, eBay, and Walmart for less than $20. Sargent says do-it-yourselfers have been making them for years. (We found mentions of these extension cords online going back to 2005.) And while you can find videos and web pages online saying they’re safe if used properly, most commenters make it clear these plugs have earned their gruesome nicknames for a reason.
Here’s specifically what’s wrong with using a male-to-male extension cord:
• Even people who think they know what they’re doing could get hurt or killed. For instance, do-it-yourselfers who use protective equipment for their home projects could wrongly assume that their protective gloves are sufficient to handle the plug, Sargent says. “The gloves are most likely not a properly voltage-rated garment,” he says. And people could trip over a male-to-male extension cord and expose the live end, leaving them and others vulnerable to shocks or electrocution. “We can’t guarantee how people are going to handle these out in the real world,” Sargent says. “It’s inherently unsafe.”
• They place utility workers at risk of shock and electrocution. Electricity fed by male-to-male extension cords can flow from the house back to the utility lines on your street and potentially shock or kill those essential workers. “Our workers, having every reason to believe they are working on ‘dead’ lines, would be exposed to this hazard,” says Allan Drury, a spokesperson for Con Edison, the New York City-based utility.
• They’re a fire hazard. If your generator is attached to your home and actively running at the same time that the municipal power comes back on, you’ve got electricity coming from two power sources at once, explains Misha Kollontai, the engineer who tests generators for Consumer Reports. “Two independent sources of power can create an overload on your electrical system,” he says. “Plus, your circuit breaker won’t protect you if you plug too much into the outlets on the same circuit as the generator. Either situation is likely to start a fire.”
• Your generator will probably get destroyed. When the municipal power comes back on, you also risk burning out your generator, Sargent says. “When there are competing sources of electricity, the power grid is going to burn out the internal workings of the generator,” he says. “You’re setting your generator up for failure.”
• You put your household at risk of carbon monoxide (CO) poisoning. The Consumer Product Safety Commission recently warned against the purchase, use, and sale of male-to-male extension cords, but highlighted a few it found on Amazon that were just a few feet long. A cord that short would require placing the generator very close to the house, which is dangerous, the CPSC stated. The odorless, colorless CO that portable generators produce is toxic and can kill within minutes. In fact, it kills about 85 Americans a year. That’s why the CPSC and Consumer Reports recommend placing a portable generator at least 20 feet outside a house, with the exhaust pointing away.
There are safe alternatives to using a male-to-male extension cord with a portable gas- or propane-powered generator. We list the preferred alternatives higher.
• Buy a transfer switch and have it professionally installed. Essentially, this device is a miniature circuit breaker panel that draws electricity from your generator instead of from the power company. When power is out, you plug your portable generator into an outdoor outlet that’s connected—through the house—to the transfer switch inside. This switch prevents electricity from dangerously flowing from two sources at once and also makes your generator more useful. For one thing, you avoid running long extension cords from each appliance or electronic device to the generator; instead, you can use your regular outlets. What’s more, you can power items that can’t be connected directly to a generator, including anything hardwired to your circuit panel (like a furnace or air conditioner compressor); appliances like electric ranges and dryers that use large 220-volt four-prong plugs; and electronics that don’t have a standard plug. Buying and installing a transfer switch costs $800 to $2,000, according to HomeAdvisor. (Read more about transfer switches.)
• Use an interlock device or kit. This metal bracket is installed on your circuit breaker panel. When in place, the interlock covers your service panel’s main cutoff switch, so you can’t switch it on while the generator is running. Once the power is back, you slide the interlock back to its usual position. Thus, power flows in only one direction, which is safer than a male-to-male extension cord. A licensed electrician can tell you whether an interlock kit meets local building codes and whether—or which—one could work with your electrical system. Interlocks are not interchangeable among different makes of electrical panels, Sargent says.
• Use properly rated extension cords. This is your only other option when you’re following CR’s recommendations to keep a running generator at least 20 feet from your home. You’ll need a separate cord for each outlet on the generator you intend to use. Make sure each cord is rated for outdoor use, and check the cord label to make sure its wattage rating is high enough to safely power the appliance you’re attaching to it. And only use electrical products that have a certification seal such as UL Solutions or ETL, which means they’ve been tested by a nationally recognized testing laboratory. Suicide cords aren’t—and never will be—certified, Sargent says. “These are rogue products,” he says.
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