Are your electrical sockets a fire risk?

Overloaded electrical sockets within the home are a common cause of house fires here in the UK and Europe. With today’s increasing demands for electrical appliances, we need more and more sockets to power them with. Unfortunately, it is possible that our homes only have a limited number of mains electricity sockets available, and in older homes that may have been wired when there were much fewer demands at the time, there are even fewer sockets.

However, the number of appliances to be plugged in is only part of the issue. The crucial matter is how much power is being drawn by the appliance. The greater the power needed for an appliance, the greater the current, which can lead to an increased amount of heat generated by the appliance, but also within the wiring too.

A common answer to the lack of sockets is to use some form of adapter to allow multiple electrical plugs to be fed from a single wall socket. Essentially there are two ways with an old-style block adapter or an extension cable with a 4-socket bar attached at one end. The block adapters are very much being phased out now and for good reason as these can be very prone to being overloaded and a fire risk. The 4 socket extension bars, particularly if correctly manufactured and are fused are generally much safer. Some even have protection circuits built in. However, it is still imperative that they are not overloaded. We have included a useful guide to demonstrate the effect of power consumption from different typical appliances and how easily the extension can become overloaded.


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What else to look for to avoid fire risks with your electrical sockets

  • A burning smell, often described as a burning dusty smell

  • Smoke or even sparks coming from the appliance or plug/socket

  • Melted insulation around the wires or casing

  • Black scorched marks around the plug or socket

  • Exposed or damaged insulation on the wiring

Check to see what the extension bar is rated for, typically it is 13 amps but some may be 10 amps or less. This will indicate the total possible load for all the used sockets, though of course, we would recommend that you keep well below that max. current. The load rating will usually be clearly marked either on the top or underside of the bar. It should be fused and the correct corresponding fuse must be installed.

Using the calculator shown, have a look at typical power ratings for household appliances. While TVs, computers and wireless routers may be relatively low, kettles, washing machines and dryers can be very high. For this reason, avoid multiple high-load appliances to the same extension bar. A prime example of this is having a washing machine and tumble drier plugged into an extension and running at the same time, watched our interview with Ian Cook of Pop Bang Colour as he tells us how he narrowly missed starting a fire in his home by having an overloaded extension for his washing machine and tumble drier.

A modern household electrical double socket with integrated USB charging sockets can be a useful benefit for charging phones, tablets etc.

Not enough sockets

If you are regularly needing to use extension cables with additional sockets (like a 4 socket or more bar), then it may be worthwhile calling in a professional electrician to add more sockets to be permanently wired into your home wiring. They can ensure these extra sockets are fully able to meet your requirements and ensure complete safety, reducing fire risks. These days it is possible to have the new sockets incorporate USB charging sockets too, not only are these very convenient to charge our mobile phones, tablets and many other devices, but avoid the extra heat generated by the transformer built into charger blocks – again potential fire risks.

You should always ensure that all electrical appliances are well made, meet the safety requirements for your country and are correctly marked and tested to CE and UKCA approvals. If you did have an electrician in your house, ask them about PAT testing – thereby they can inspect every electrical appliance in the house to ensure it is safe without any possible wiring defects that could lead to increased fire risk from an electrical fire.

Since the overloading of sockets can lead to heat generation, one should therefore consider adequate ventilation around the socket to aid cooling but also ensure that there are no flammable items close by which can ignite due to the heat generated.

As we have already mentioned naked live wires or those with damaged insulation can lead to short circuits or even arching whereby electricity can jump from wires close to each other. Not only can this generate significant heat in or around the appliance leading to fire, but the spark could also directly hit a flammable object, again resulting in fire.

Finally, we would also highly recommend the avoidance of “daisy-chaining” extension cables. This is the practice when the appliance is some distance away from the nearest available socket as multiple extension cables are plugged into each other in order to create one extra long cable. Again this can also lead to an increased fire risk.

Fire Risks

  1. Heat Generation: Overloading a power socket leads to an increase in electrical current flowing through the wiring. This excess current generates heat, which can cause the insulation on wires to degrade over time. Damaged insulation exposes wires to potential contact with flammable materials, greatly increasing the likelihood of a fire starting.
  2. Short Circuits: When too many devices draw power from a single socket, it elevates the risk of short circuits. A short circuit occurs when the electrical current bypasses its intended path and travels through an unintended route. This can cause sparks, which, if near combustible materials, can ignite a fire.
  3. Arcing: Overloaded sockets can result in arcing, a phenomenon where electricity jumps from one wire to another due to high voltage or poor insulation. Arcing generates intense heat and can lead to fires, especially if the spark ignites nearby materials.
  4. Melting of Components: The increased current passing through the wires and connectors can cause them to heat up excessively, leading to the melting of plastic components. Melted components can drip onto other materials, causing fires.
  5. Inadequate Ventilation: Overcrowded power sockets often lead to poor ventilation around the plugs and cords. Accumulation of heat in confined spaces can cause materials to heat up beyond their ignition point.

Preventive Measures:

  1. Limit Device Use: Be mindful of the number of devices connected to a single power socket. Unplug devices that are not in use to reduce the load on the socket.
  2. Use Power Strips Wisely: If you need to connect multiple devices, use a high-quality power strip with surge protection and individual on/off switches. This allows you to manage the load more effectively.
  3. Check Power Ratings: Ensure that the combined power ratings of all connected devices do not exceed the socket’s capacity. Consult the manufacturer’s guidelines for information on power ratings.
  4. Inspect Wiring: Regularly inspect power cords and plugs for any signs of damage or wear. Replace damaged cords promptly to avoid potential hazards.
  5. Spread the Load: Distribute the load across different power sockets rather than concentrating all devices in one area.

Credit: article on ‘Overloading Sockets’