Is My Extension Cord Overloaded? (Easy Guidelines)

Extension cords are great at allowing users to connect more devices to the same power outlet. For example, it helps ensure we have our computer, speakers, and printer all close by and power on.

However, it’s important to understand that there are limits to consider when using extension cords and that not using them correctly can result in overloading them.

What Happens When Your Extension Cord Is Overloaded

If your extension cord is overloaded then you have exceeded its total capacity of watts it can handle. When this happens, your extension cord poses a safety risk and you have an increased likelihood of fire due to sparking which may damage your devices.

Extension cord rolled up

It is essential that you understand how to calculate how many watts your extension cord can take before it becomes overloaded.

How Many Devices Can You Connect To An Extension Cord?

It’s easy to believe that you can plug as many devices into your extension cord as the cord provides.

Let’s say you have an extension cord with six sockets – it’s always tempting just to fill each socket with a device.

However, it is not a question of how many devices can be connected, but rather, how much wattage each device needs.

You always need to work out whether the appliances that you wish to connect will exceed the threshold of your outlet, and in this case, your specific extension cord.

If the total amount of devices has a combined total wattage that exceeds the threshold of your specific cord then you are in dangerous territory and it may pose a fire hazard.

Remember, sometimes even small appliances, such as kettles can require far more watts than you’d expect.

Here’s an example of how devices differ in wattage from another:

  1. Mobile phone charger
    • 12W
  2. DVD Player
    • 28W
  3. Radio
    • 40W
  4. Lamp
    • 60W
  5. Fridge
    • 150W
  6. Toaster
    • 2000W
  7. Washing Machine
    • 2200W
  8. Iron
    • 2800W
  9. Kettle
    • 3000W

As you may have observed, the size of the appliance is not a factor when it comes to the amount of power these items use.

Therefore, when considering how many devices you can plug into your extension cord you must understand the load that the extension cord can hold.

How Much Load Can An Extension Cord Hold?

A power outlet can safely provide 3000W, anything over this should be considered dangerous.

When working out how much load your extension cord can hold you need to consider the exact amount of watts each device needs and what your extension cord has the capacity for.

You should always check what your extension cord can handle as they do differ, but they average around 3000W or 13A.

When calculating what would overload your extension cord you will need to conduct the following sum:

Amps multiplied by voltage = watts.

For example, as you have noted from our list above, a kettle needs 3000W. This means that you should never really have a kettle and any other device attached to an extension cord at one time.

Now consider having let’s say a toaster (2000W), and microwave (1500W), plugged into the same extension cord. In this case, you will have exceeded the capacity of a 13A cord by 500W.

Lower voltage items such as mobile phone chargers, radios, and lamps, will have a total wattage far below that 3000W threshold and are therefore perfectly safe to connect without overloading most cords.

Some extension cords do offer cords that can allow you to exceed the 3,000W mark, but not by much.

For example, the company Brennenstuhl offers a cord that can handle a total of 3,500W. Remember to check your model for its exact maximum load.

Read out blog here about do extension cords reduce power?

How Do You Know If An Extension Cord Is Overloaded?

You really want to avoid being in a situation where your extension cord becomes overloaded and, by following the advice mentioned above, it shouldn’t happen.

However, there are some tell-tale signs that your cord is overloaded:

  • Any indication of smoking or sparking from either the device or plug socket
  • The smell of burning plastic.
  • Dark burn markings in the vicinity of the plug or the socket.
  • The appearance of damage to the leads of the device.
  • Signs that the plastic has melted on leads or the casing of the plug.
  • Blown fuses.

If you notice any of these signs that your extension cord is overloaded then it is crucial that you stop using it immediately. 

Do Extension Cords Switch Off When Overloaded?

Some extension cords are designed to automatically switch off or cut out when they receive an intake in voltage that is too high or a surge in wattage.

When extension cords are overloaded they will either:

  • Switch off permanently until they are switched back on again.
  • Switch off temporarily then turn on automatically after a few minutes.
  • Cut power to certain appliances plugged in, but leaving some working still.

This is because some extension cords contain certain safety measures such as surge protection mechanisms or circuit breakers, which in turn prevent too much electricity from passing through which could result in an electrical fire.

There are particular appliances to watch out for such as vacuum cleaners and food processors that have the ability to create power surges, which will in turn overload and trip your extension cable, causing it to switch off.

When an extension cord has been overloaded once, it is likely that an electrical mechanism inside has been damaged.

Each time this happens, the chances of an internal faulty mechanism become even higher.

Therefore, after a surge that has caused your extension cord to switch off happens multiple times, it is worth thinking about getting a replacement.

The cord will no longer be able to provide the same protection as it once could.

It is worth noting whether the extension cord has the appropriate amp rating for the appliance or devices you are wishing to connect in order to prevent overloading in the future.

Can Extension Cords Be Daisy-Chained?

Problems can arise when using two or more extension cords in unison; otherwise known as ‘daisy chaining’.

Connecting multiple extension cords together can result in:

  • Increased electrical fire hazard risk
  • Overloaded circuits
  • Trip hazards

Nowadays, you are able to purchase extension cords that have multiple sockets which are designed to handle a higher amount of wattage passing through.

In terms of EHS (Environmental Health and Safety), daisy-chaining accounts for a number of OSHA (Occupational Safety and Health Administration) violations.

However, sometimes you may have no other option other than to daisy chain your extension cords.

Remember, daisy-chaining is never a recommended practice.

There are fortunately ways to avoid daisy-chaining or make it safer to do so, such as:

  1. Always try to use extension cords that have a long wire as opposed to daisy-chaining multiple short cords together. These longer extension cords are readily available and diminish the potential hazard.
  2. When you are in a workspace, try and re-organize the furniture or desks so that you are nearer to an actual plug socket. It’s always far less risky to rearrange furniture than to try and daisy chain extension cords.
  3. Ensure you check the conditions of the extension cords before you connect them. Loose or broken wiring will only add to the electrical fire hazard risks.
  4. Never use extension cords continuously for longer than 90 days as this increases the risks of injury or fires. Extension cords are designed as temporary wiring; once you have surpassed 90 days, it is no longer considered temporary.
  5. Make sure all cables are visible and not covered by carpets or other items.
    • Connecting multiple extension cords is not only a trip hazard if they are not visible to workers, covering them can create overheating- increasing the risk of an electrical fire.

Check out our blog here about do extension cords have surge protectors?


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