An extension lead should only be used when it is not possible to reach a wall socket with the equipment cable
Answered by Sarah, Electrical Safety Expert
An extension lead should only be used when it is not possible to reach a wall socket with the equipment cable. When the use of an extension cable is unavoidable – follow these simple suggestions:
Only use an extension lead which was bought ready-assembled.
We recommend that no extension lead be more than 15 metres long.
Only use extension leads fitted with suitably insulated connectors and plugs. (Never join two lengths of flexible cable by twisting the bare ends of wires together.)
Position an extension lead carefully to prevent any risk of damage.
If the cable has to cross a pathway, cover it with a rubber protector strip.
Always check that leads, plugs and sockets are undamaged.
Always check the extension lead plug contains the correctly rated fuse for the equipment being used.
If using a cable drum extension lead, it should be completely unwound to avoid overheating.
For general use, 2-core extension leads should not be used. Even if there is space to plug in four appliances to the extension lead, this does not mean it is safe to do so.
Use our overload calculator to check if you are exceeding the maximum load - https://www.electricalsafetyfirst.org.uk/guidance/safety-around-the-home/overloading-sockets/.