Do Extension Cords Damage Chargers? (We Checked)

Extension cords can be used to power your devices while you’re away from an outlet. But should you use them? Here’s what you need to know.

Extension cords come in handy when you want to use a device without being too close to the outlet. But do they damage the charger or battery?

In this article, we’ll explore whether or not using an extension cord damages chargers and if there are ways to prevent this from happening.

Here’s If Extension Cords Damage Chargers

Most modern chargers are designed to handle being plugged into an extension cord. However, some chargers are not and they can be damaged by using them with an extension cord. In most cases you should stick to the factory charger and cable only in order to protect your phone and charger.

The extension cord lies on the floor with a large current consumption. The concept of high energy consumption, dangerous fire.

Here’s why:

  • Most chargers have a built-in circuit breaker that shuts off power when too much current flows through the charger. This protects both the charger and your device from getting fried in case of a short circuit or overload condition.
  • If you use an extension cord with such a power-hungry device as a hair dryer or space heater, the total current flowing through the extension cord may exceed what it can safely handle. In this case, the circuit breaker in your charger will trip and turn off power before harm can be done to either your device or your charging cable.

Do Extension Cords Affect Chargers in Any Way?

They do affect but the degree of affect varies depending on a few things like:

  • The first thing to consider is the length of the extension cord. If it’s too long, then you may have problems with voltage drop (the reduction in voltage from one end of an electrical circuit to another).
  • A second thing to consider is whether or not the extension cord has a fuse. A fuse will help protect your charger from overloading and overheating, but if the cord is damaged or frayed, then that fuse could fail and leave your charger unprotected.
  • Finally, if you’re using an old extension cord, or if it’s frayed or damaged in any way, then you could be at risk of causing serious damage to your charger. This is especially true if you’re using the wrong type of extension cord for the job.

Is It Recommended to Not Use Extension Cords with Chargers?

All electrical appliances, including chargers, are designed to be used within a specific voltage range. This is usually 120 volts, but some items may operate at 240 volts or even more. If you use a charger outside of its specified voltage range, it can damage the device and even pose a safety risk to you and others around you.

While there’s nothing wrong with using an extension cord with your charger, it’s not recommended that you do so unless absolutely necessary. The best way to make sure your charger works safely is to use the one that came with it.

When you plug an extension cord into a wall outlet, it creates a circuit that extends the length of your wall socket. The wire in this circuit is usually copper, which is a good conductor of electricity.

In comparison, the wires inside a charger are typically made of aluminum or tin-coated copper, which aren’t as efficient at conducting electricity. This means that when you use an extension cord with a charger, there’s more resistance in the circuit than if you used just the charger alone.

The increased resistance causes more heat to build up in both ends of the extension cord — at your outlet and at your device’s charging port.

This heat is essentially wasted energy — it doesn’t do anything for you except make your device warm while charging and potentially shorten its lifespan by increasing wear on components like batteries and electrical contacts. In extreme cases, overheating can even cause fires or other serious problems.

There are other things that can damage chargers, such as:

  • Overheating. All chargers have a maximum wattage rating, which is usually around 2,000 watts for smaller models and up to 3,600 watts for larger models. If you’re charging multiple devices at once or charging devices that draw more power than the charger can handle, it can overheat and cause problems with both the charger itself and the device being charged.
  • Water damage. Water can get into a charger through several different areas — especially if it’s wet outside or if there’s flooding in your home or office building. Water can also get into some chargers through the electrical connections if they aren’t properly sealed against moisture. If water gets into your charger, it could cause electrical shock or even a fire hazard if it reaches an internal component like a motor or heating element.
  • Overloading circuits. This occurs when too much current flows through the circuit at once — either because too many devices are plugged in at once.

Check out this other blog about can extension cords be left outside?

Is It OK to Use an Extension Cord with Phone Chargers?

The answer is that it depends on the type of extension cord and charger you are using.

The most common problem is when you use an extension cord with a charger that is not built to handle the extra current draw. For example, if you’re using a smartphone with a USB port to charge, it’s better to use a standard USB cable instead of an extension cord.

Here’s why:

  • The USB ports on your computer or TV only handle about 500mA (0.5A) of current. If you’re charging a device that draws more than 500mA from the port, then it won’t work correctly because there isn’t enough power available in the port to handle it.
  • The same goes for any other device that doesn’t have its own power supply — like tablets and eReaders — because they also draw their power from one of those two sources (your laptop or TV).
  • But what about charging devices that don’t need their own power supply? Well, there are two types of them: those that use adapters (like Apple products), and those that plug directly into an outlet (like smartphones).

How Is a Charger Damaged by Extension Cords?

When a charger overheats, it can cause damage to the internal components inside the device.

The main part of a charger that gets damaged by extension cords is called an input filter — this is where electricity enters into your device, and it helps prevent it from getting overloaded.

When an extension cord causes too much heat in this area, the filter starts to melt and will eventually break down completely.

Does Using an Extension Cord Affect Charging Speed?

Yes, using an extension cord can affect the charging speed of your device. The length of the extension cord you use and the quality of it will determine how much it slows down your charge time.

You should avoid using any extension cords longer than 3 feet when charging your devices. This is because they may not be able to provide enough current (amperage) to support fast-charging technology like USB-C.

A way work this out is that, if you for example have a 10-foot long extension cord and the charger only needs 5 watts of power to charge your phone, then it should have no problem charging at full speed.

However, if your device needs 20 or more watts of power to charge fully, then the charger may struggle with this load and not be able to supply enough current for quick charging.

This is because most extension cords don’t have as high of voltage as wall chargers do.

Can You Leave an Extension Cord with Chargers Plugged In?

The short answer is yes, you can leave your device plugged in when not in use. However, there are some things you must consider before doing so.

First of all, make sure that your charger has a safety feature that shuts off the power from the outlet if it detects a short circuit or if the device overheats or catches fire. If not, then you may be risking your device’s life by leaving it plugged in for a long period of time (more than 24 hours).

If your charger doesn’t have this safety feature built-in, then make sure that you unplug it after every use to prevent any damage to your device.

Also keep in mind that leaving chargers plugged in over time can cause them to wear out faster than they should have; especially if they’re not designed for such continuous use.


Extension cords and charging devices don’t mix. They both increase the risk of something going wrong, whether that’s the possibility of an electrical fire or an electric shock while you’re disconnecting a charger.

Fortunately, while it’s not a guarantee, in most cases—should you feel comfortable with the quality of the extension cord and the wall outlet—there should be little to be worried about.

Read our blog here about do extension cord expire or work permanently?


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