Can You Plug a Smart Plug into a Power Strip or Extension Lead?

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Smart plugs are a great way to retrofit any device in your house so that it can become part of your smart home ecosystem, adding voice control and routines.

If you’re short on plug sockets, you might be wondering if you can plug a smart plug into a power strip?

Yes, it’s safe to plug a smart plug into a power strip. However, you should not exceed the maximum wattage of either device. A power strip will usually have a 13amp rating, this means that you should not exceed 2990W across all sockets on the power strip.

In the rest of this guide, I’ll break down how to work out the maximum power for your power strip and smart plug as well as a far better alternative option.

Can You Plug a Smart Plug into a Power Strip?

Yes, a smart plug will work in a power strip and is completely safe to do so as long as your devices across the power strip do not exceed the maximum capacity.

All smart plugs will have an amperage rating. This is usually 10 or 13 amps.

The formula to calculate how much you can plug into a socket is: Amps x Volts = Watts.

Therefore, based on the UK’s voltage of 230v, you can plug up to 2990W into a smart plug with a 13amp rating.

If you’ll be regularly using smart plugs on your power strip, a better option might be to consider a smart power strip instead. The TP-Link Kasa Smart Power Strip allows you to individually control each device on the power strip, more details on this below.


Can You Plug a Power Strip into a Smart Plug?

Alternatively, if you’re hoping to make the entire power strip smart, you might be wondering if you can plug a power strip into a smart plug?

Yes, you can plug a power strip into a smart plug. You should check the amperage of both the power strip and the smart plug, then use the lower of the two to calculate the maximum power of all devices on the strip.

Typically, both the power strip and smart plug will have a 13amp rating, in that case, you should ensure a maximum of 2990W across all electrical devices plugged into the power strip.

If the smart plug has a lower 10amp rating, the maximum capacity across the power strip will be 2300W. This applies even if the power strip has an amperage of 13amp because you use the lower of the two.

Remember, this must be divided across all devices on the strip. If you have 3 devices plugged in, they should use no more than 2990W or 2300W between them.

Again, a better alternative is a smart power strip, see the next section for a recommendation.


Alternative Recommendation: Use a Smart Power Strip

Instead of plugging smart plugs into power strips or vice versa, a better option is to use a dedicated smart power strip that has the smart features built right into the strip itself.

These will allow you to control each device on the strip using a companion app and often will integrate with Alexa, Google Home, and other smart home ecosystems.

This is much easier as you no longer have bulky smart plugs blocking other sockets on your strip.

Also, you only need to worry about the amperage of a single power strip and it prevents difficulty plugging multiple devices into a strip which can occur due to bulky smart plugs.


What’s the Best Smart Power Strip?

The product I recommend is the TP-Link Kasa Smart Power Strip. The reason I recommend this product is due to the physical switches next to each outlet in addition to the smart features.

This means you can still turn devices on and off individually even in the event of your internet going down or some other service outage.

It has 3 power sockets plus 2 USB ports. Although, the USB ports are always powered on and don’t have smart control.

See my full guide to the best smart power strips in the UK for a full review and other products.


Can You Plug a Smart Plug into an Extension Lead?

Another common question I am asked about smart plugs is whether you can plug them into an extension lead.

Yes, it is fine to plug a smart plug into an extension lead or vice versa. It’s best to check the amperage of both the extension lead and the smart plug, then ensure any connected device does not exceed the lower of the two.

The same formula used above is also applied here. If the lower amperage is 13A, do not exceed 2990W, if the lower amperage is 10A, do not exceed 2300A.

It does not make a difference if the smart plug is connected before or after the extension lead so I would recommend you choose the location that is closest to your Wi-Fi router for maximum connectivity.


Is it Safe to Use a Smart Plug with a Surge Protector?

Many power strips and extension cables will have built-in surge protection as a key selling feature. A surge protector prevents too much current from being drawn by devices on the power strip which could result in overheating and cause damage to your device, or worse a fire.

Most smart plugs don’t have any built-in surge protection as this would make them even bulkier than they already are. For this reason, you may be considering using a smart plug with a surge protector, but is this safe?

Yes, it’s safe to use a smart plug-in tandem with a surge protector. As with regular power strips, it’s important to observe the amperage of both the smart plug and the surge protector, then use the lowest of the two to calculate the maximum power.

Calculating the maximum wattage is the same as before. Based on the UK’s 230v mains power supply:

  • If the lower of the two is 10A, then your device(s) should use no more than 2300W
  • If the lower of the two is 13A, then your device(s) should use no more than 2990W

Kieren

I have been building up my smart home since 2016 so I'm a bit of a smart home expert by now. On this blog, I share my favourite smart home devices that I've tested along with tips and tricks I learn by watching countless YouTube videos, scrolling through forums, and tinkering around with my own smart devices. I've always been a Google Home user but I'm starting to think Alexa might have the edge, what do you think?