How to avoid overloading your plug sockets at home

Overloading your plug sockets with multiple electric appliances can be tempting, but just because your extension lead can squeeze in four plugs doesn't mean it's safe to do so.

Some appliances require so much power that, when grouped together, they can cause the plug to overheat and possibly start a fire.

To help you stay safe, we've listed the most energy-guzzling appliances below to help you understand what devices - when used in tandem - might overload your sockets.

We also look at whether it's safe to leave your phone or laptop charging overnight.

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How much power do your appliances need?

Surprisingly, some of the smallest appliances in our homes use the most watts of power.

In fact, a kettle actually uses 20 times more watts than a fridge. And an iron uses a staggering 2,800 watts - that's more than 200 times more than is needed to power a mobile phone charger.

As a guide, you should only load one plug socket with a maximum of 3,000 watts. But it might be easier to remember the sorts of products that require more and less around the home. 

If you're not sure which appliance works with which, then take a look this handy socket calculator.

Are overloaded plug sockets a fire hazard?

We asked Tim Behnam, technical support officer from Royal Berkshire Fire and Rescue, how many plugs are too many when plugging devices into an outlet.

He said: 'It really depends on the appliances you're plugging in. Always work out the total wattage of all the devices going into the one socket.

'If they add up to more than 3,000W then it's not safe - the plug in the socket can overheat and potentially cause a fire.'

Here are four examples of what not to pair up using an extension lead. 

'A kettle can max out the socket capacity all on its own, while having your washing machine and dishwasher plugged into an adaptor would mean you're a massive 1,440 watts over the recommended amount,' he said.

'Appliances like your fridge, radio or lamp are far more suited to sharing sockets. Take note if you're moving plugs around to try to squeeze extra devices in.'

Is it safer to pair appliances alongside each other in a twin-outlet plug?

'While each socket usually in a twin-outlet plug is rated to 13 amps and, in theory should be able to handle that load, we wouldn't advise doing this,' said Mr Behnam.

'If you suspect one plug in a twin-outlet socket is heavily loaded, try to only use low-power devices in the other one, just to be on the safe side, or use a different socket.'

And is it really a bad idea to connect one extension lead to another one?

'Yes it is,' he said. 'You should never "daisy-chain" extension leads together. If you use more than one extension lead per socket it will significantly raise the risk of overloading the socket.'

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Are block plug adaptors dangerous?

Fire safety experts prefer extension leads to block plug adaptors, provided they are used correctly, Mr Behnam said.

'Block adaptors aren't unsafe but the weight of the plugs and the leads can start to pull the adaptor out of the wall socket leading to resistance heating and increasing the risk of a fire,' he said.

'Plastic block adaptors that have lots of sockets and sometimes come without a fuse are always best avoided.'

He added there were risks to buying cheap extension leads from online marketplaces.

'Be wary of cheap extension leads - they are almost always cheap for a reason. It's not worth the risk,' he said.

'The best way to protect you and your family from potentially dangerous goods is to buy from a reputable retailer.'

Should you charge your phone overnight?

He also warns care should be taken with USB charging.

"Adaptors with several USB charging ports can also be overloaded," he said.

"Take care not to charge laptops or mobile phones overnight and ensure you don't plug too many items into the same adaptor at any given time.

"We advise people to buy electronic goods from reputable retailers and to stop using them immediately if their chargers are showing any signs of heating or damage."

Seeking to buy a new phone? Read our mobile phone reviews.

How safe are smart plugs?

It's not just cheap plug adaptors that pose a risk.

A recent Which? investigation found cheap smart plugs - plug-in gadgets that help you control your appliances remotely - could expose you to hackers or even start a fire.

Working with security consultants NCC Group, we found 13 vulnerabilities among nine of the plugs we examined, including three rated as high impact and a further three as critical, including one that could cause a fire in your home.

A smart plug turns a traditional electrical outlet into a smart home system. You can use one to turn on lights with an app or your voice, or monitor the power consumption of appliances, such as a fridge. But doing proper research before you buy is essential if you're to avoid the issues we found.

Do your research before you invest in smart products. Read how to buy the best smart plug.

What are surge protectors for, and when should you use them?

A surge protector is an appliance or device designed to protect electrical devices from voltage spikes.

A surge protector attempts to limit the voltage supplied to an electric device by either blocking or shorting to ground any unwanted voltages above a safe threshold.

Surges are typically produced from:

• Internal tripping events, such as lighting being turned on and off.
• A high energy inrush generates a surge which continues around the circuits and can damage sensitive electronic equipment.
• Direct lightning strikes can also produce huge surges from up to 2km away. Surges can be induced in cabling systems, even when there is no direct connection to the point of a lightning strike.

A surge protector can absorb only so many surges before it stops functioning. Although it's practically impossible to tell exactly when this happens, the longer it's been used for the more at risk you are. If it's absorbed a serious power surge you should always replace it immediately.

Some surge protectors have built-in lights designed to alert you when it needs to be replaced. But you can't fully rely on this - it's not a foolproof system.

As a rule of thumb, a surge protector should be replaced at least every two years.

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