Extension leads can be a saviour as they can enable you to use more appliances than you have native sockets for, and they can also help you reach areas where you may not have a direct supply. However, they can also become a hazard, whether at home or at work, especially if they’re misused.

Many extension leads will have space to plug in at least three items, but just because the spaces are there it doesn’t mean that it’s always safe to do so. There’s a risk that the appliances you plug in may combine to overload the lead and the socket, so it’s important to exercise caution.
Begin by checking the extension lead’s current rating before using it. The majority are rated at 13A but it’s possible that yours might be rated at 10A or even lower, and this will usually be marked on the underside of the extension lead housing. Knowing the rating will allow you to gauge which appliances – and how many – you can safely connect. Adding too many appliances may cause the lead and the socket to overheat and even to catch fire.
Electrical Safety First have provided a helpful overload calculator which you can use to make your assessments:
Please enable JavaScript to use the Socket Calculator.
The Socket Calculator has been brought to you by Electrical Safety First.
For more safety information visit https://www.electricalsafetyfirst.org.uk
The simple rule of thumb when it comes to extension leads is only to use one per socket and never to connect one to another. Historically, what are known as block adaptors were popular, but we recommend ditching those in favour of much safer multi-way bar extension leads, largely because this avoids excessive strain on the socket. And if you’re regularly finding yourself using an extension lead, why not add some extra sockets to accommodate your needs?
Telltale signs of potential safety issues with your sockets and extension leads include:
- a smell of burning
- sparks or smoke coming from your appliance, socket or extension lead
- scorch marks around the socket or on the plug
And if either your appliance or the extension lead itself has signs of wear and tear, such as fraying, it should immediately be repaired or discarded.
Finally, the festive season is probably the busiest time of the year for extension cables as we never seem to have enough sockets available, so please check them and your Christmas lights carefully before switching them on. That way you’ll keep your electrical safety in check throughout all the festivities…
At MS Electrical we specialise in PAT testing in Cambridge. Simply call us on 01223 850301 or complete our enquiry form to request a no-obligation quotation.