6 times using an extension cord could put you at risk

Plugging in major appliances

"No extension cords whatsoever," said Paul Martinez, owner of Electrified NYC in Brooklyn, in an interview with tech site CNET.

He noted that appliances such as air conditioners, microwaves, and refrigerators, which run continuously, as well as any device with a heating element, should always be plugged directly into a wall outlet to prevent risks.

Tim Hodnicki, master electrician at Electrical Experts, added that the high power draw from such appliances may easily overload an extension cord, causing it to overheat and potentially start a fire.

Using as a substitute for permanent wiring

Extension cords are intended for temporary use and should never replace permanent wiring, experts say.

"Over time, extension cords can wear down, overheat, and become a fire hazard," Joel Worthington, president of U.S.-based electrical services company Mr. Electric, told lifestyle site Martha Stewart.

If continued use is unavoidable, he recommended replacing extension cords regularly to reduce risks.

Chargers plugged in to an extension cord. Photo from Instagram

In outdoor or wet environments

Standard extension cords are not designed for outdoor use, particularly in wet or humid conditions. Even when weather appears stable, prolonged exposure to sunlight and fluctuating temperatures can damage the cord's insulation.

"Even if they look fine, they can crack or short out," said Ryan Gregor, owner and head electrician at Australian firm RCG Electrical, in comments to lifestyle site The Spruce.

Hodnicki added that indoor cords are not built to handle moisture or temperature extremes, and using one outdoors increases the risk of electrocution or short-circuiting.

When cooking

Kitchen appliances often require more energy than extension cords can safely supply, experts caution.

"Small kitchen appliances draw more power than their size suggests," said Daniel Mock, vice president of operations at U.S.-based Mister Sparky Electricians, as quoted by Martha Stewart. "Toasters in particular use internal wiring that heats up quickly, which can easily overload an extension cord."

Worthington advised that devices like slow cookers and hot plates should always be plugged directly into a wall outlet. "Extension cords are typically not rated for prolonged use and can overheat under continuous load."

Plugging in multiple devices

Connecting several devices to a single extension cord can lead to overheating and circuit overloads, particularly if they require high power.

"Don’t plug multiple high-powered devices into the same cord," Worthington warned. "Devices like computers, printers, and TVs plugged into one cord can exceed its capacity and cause overheating."

Mock noted that this could overload circuits and cause fires, or at minimum, overheat the cord and damage connected devices.

Charging electric bikes or scooters

Electric scooters, bikes, and other personal mobility devices often require more power than an extension cord can handle.

The Electrical Safety Foundation International recommends using only manufacturer-approved chargers plugged directly into a wall outlet.

"Extension cords should be treated as a temporary solution – not a permanent one," Mock said.

"Many inappropriate extension cords don’t provide the power some of these e-bikes and scooters need to charge properly and if used incorrectly, it could cause the extension cord to overheat and cause a fire."