Can You Overload an Extension Cord? (Easy Guidelines)

If you’ve ever plugged too many appliances into a single extension cord, you know what happens. The lights dim, the TV buzzes and you get a weird smell.

This is a sign of a faulty electrical connection and could mean that your extension cord is oveloaded.

In this article I will talk about if you can overload an extension cord and what safety measures you can take.

Here’s If You Can Overload an Extension Cord:

You can overload an extension cord. But it depends on the type of extension cord you’re using. In general, it’s best to avoid overloading your extension cord at all costs because they are not designed to handle the extra load and can potentially cause a fire.

Extension electric cable reel isolated on white background

Can Standard Extension Cords Be Overloaded?

The short answer is simple: yes, you can overload an extension cord. However, it’s not as easy as just plugging in more than one appliance into the same extension cord.

This is because the maximum amperage for an extension cord is 14 amps.

If you exceed this amount of power, it could overheat and cause damage to your appliances and even start a fire.

How Much Current Can Extension Cords Handle?

The amount of current an extension cord can handle depends on the gauge of its wiring and how much resistance it encounters.

The lower the gauge number, the thicker the wire is and the more resistance it has to heat buildup. Lower gauge numbers also mean greater flexibility for handling curves and bends in the cord.

The maximum allowable amperage for extension cords varies by state and even by county within states, but as a general rule, 14 AWG (American Wire Gauge) extension cords should not be used with appliances that draw more than 15 amps per circuit.

In addition to overloading an extension cord, this practice could result in fire or electrocution if you accidentally plug one end into a live outlet while using another end to power an appliance.

What Can Cause an Extension Cord to Overload?

Overloading occurs when you use too much power for the length of the cord. For example, if you have a 100-foot extension cord but only need 50 feet to reach from the outlet to your appliance, then the remaining 50 feet of cord will be carrying electricity that it simply isn’t designed to handle.

The same principle applies if you try to use multiple appliances on one extension cord. For example, don’t plug in several power tools at once because this could overload the cord and cause it to overheat or even catch fire.

The following are other common causes of overloads:

  • Using an undersized extension cord: Always use a heavy-duty extension cord (if possible) when using large appliances such as air conditioners or electric lawn mowers because they draw more current than smaller devices like lamps and fans do.
  • Using too many appliances on the same circuit. According to the National Fire Protection Association (NFPA), this is the leading cause of electrical fires in residential homes. If you have too many appliances plugged into one outlet or cord, it may overheat and start a fire. This is especially true if any of those appliances are heating devices such as hair dryers or irons.
  • Plugging too many cords into one outlet strip or multi-outlet strip. These strips provide multiple outlets but only so much power from each outlet strip’s circuit breaker or fuse box. If you plug too many devices into one outlet strip, it can trip the breaker or overload the circuit and cause sparks that ignite nearby combustible materials (like paper or wood).

According to the U.S. Department of Labor’s Occupational Safety & Health Administration (OSHA), there are two main dangers associated with overloading an extension cord: overheating and fire hazards.

Overheating can occur when too much current flows through a wire or cable at once — this is called “circuit overload.”

The result is heat buildup inside the cord or cable, which causes damage to its insulation and internal wires. And if a wire or cable gets too hot, it can start a fire by itself or because of its proximity to other flammable materials around it (like newspapers).

If a cord or cable overheats from too much current flowing through it, it will melt its outer insulation layer, exposing its internal wires and causing short circuits that can cause sparks and flames near flammable materials like paper products.

What Should You Do if Your Extension Cord Overloads?

If your extension cord overloads, unplug it from both ends immediately and leave it unplugged until you can replace it with a safer one.

The National Fire Protection Association (NFPA) recommends replacing any damaged extension cords immediately because they are more likely to fail again than ones that aren’t damaged in any way (including being overloaded).

How Do I Know If an Extension Cords Can Switch Off During Overload?

Some extension cords have built-in safety features that will shut off if they become overloaded with power.

However, some do not come with automatic shutoff features and therefore it’s up to you to monitor the amount of wattage being used by your appliances at all times during use.

You’ll need to keep an eye on both the length of time being used as well as how much power is being used by each appliance plugged into it at once.

How Do You Know If an Extension Cord Is Overloaded?

If you have more than one appliance plugged into one extension cord, then there are two ways that you can tell if it’s overloaded — by checking the wattage rating and by checking the amperage rating:

  • Wattage Rating: The wattage rating refers to how much power each device draws from an outlet or extension cord. This value is usually printed on the device itself or on its packaging. For example, if you’re using a 60-watt light bulb with a 60-watt extension cord, you’ll need to add up both values to get 120 watts total — which means your extension cord isn’t overloaded,
  • AMP Rating: The first thing to consider is how much current a certain device draws from the wall. This would be measured in amps (A). For example, an iPhone 6S Plus draws about 2.4A when charging, which means your extension cord needs to be able to handle that amount of current without melting or catching fire (more on this later).

Do Extension Cords Switch Off When Overloaded?

The answer to this question is yes, but not always. In fact, many times they won’t switch off and instead just melt or catch on fire.

This can be due to several factors including how heavy the load is and how much current your extension cord can handle. The best way to know if your cord will shut off when overloaded is to check its amperage rating.

In order for it switch off, the current flowing through the cord must be above its rating. The rating is based on the wire size and the length of the extension cord.

For example, a 10-gauge extension cord rated at 15 amps should be able to handle up to 150 watts (10 x 15 = 150) before it begins to overheat and shut down.

Tips To Not Overload Extension Cords

Use only an extension cord that is rated to handle the current flow of your device or appliance. For example, a 15-amp extension cord should only be used on equipment that requires 15 amps or less (like a small vacuum cleaner).

If you use it on something that draws more power than that, it could overheat or melt down.

Don’t run cords under carpets or rugs because this can cause overheating in the wires inside the insulation material.

Keep cords away from high heat sources like stoves or radiators, too — again for fire safety reasons as well as for electrical shock prevention during winter months when heating systems are running full blast indoors.

Plug only one appliance into each extension cord or power strip at a time when possible. If you try to plug more than one item into a single outlet, it may overload the outlet and cause a fire.

Never connect two cords together and plug them into an outlet; this also overloads the outlet and can cause a fire.

Use heavy-duty cords with built-in circuit breakers: 

  • These types of cords have built-in safety features that help prevent overheating and overloads from occurring, which means they’re safer than standard extension cords with no built-in circuit breaker.
  • However, if you decide to use standard extension cords instead of heavy duty ones with built-in circuit breakers, make sure that they’re rated for use indoors only (not for outdoor use).
  • Outdoor cords are not insulated well enough for indoor use because they don’t provide adequate protection from moisture or rain.


Some people think that extension cords are meant to be overloaded due to the fact that they are essential in enhancing our mobility.

In reality, there is a limit where you should not cross when using an extension cord for the sake of your safety. When buying one, look for those labeled as heavy duty, which can handle much more load than standard ones.

Check out this blog about should you unplug an extension cord when not in use?


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