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Worried About Overloading Sockets? – Try This Calculator

The 13 amp Rule Explained


Spotlight Safety Feature – Irvine Beat FM

Q: How many appliances can you plug into one socket?

A: Follow the 13 amp rule as explained in this article.

Q: How do I know if I am overloading a mains socket?

A: Different appliances draw different amps. Use our calculator on this page as a guide to avoid overloading.

Q: How many watts can a 13 amp socket take?

A: Plugging in 4 items such as a TV, DVD player, Sky Box and games console to an extension , would amount to just over 750 watts = 3 Amps.
It is important to never overload a plug socket, which is 3000 watts = 13 Amps. Some appliances use more than others. Use the calculator on this page as a guide.


Overloading electrical sockets can cause plugs to overheat and result in fire.


What is the 13 amp rule? 

Taking a few seconds to read these guidelines & check your fire alarm could save not only your own life, but that of your families too.

If you are unsure what appliances consume more power, try the socket overload calculator on this page as a guide.

Here are the recommendations by the ESC (National Electrical Safety Council).


  • Do Not Overload Sockets. Remember the 13 amp rule. A maximum of a total of 13 AMPS into 1 socket.
  • Avoid block adaptors. Use bar adaptors on a cable. (Some block adaptors do not have a fuse therefore increase the risk of overloading and fire).
  • When you are going to bed or when they are not is use, unplug appliances.
  • Do not run extension leads under carpets.
  • NEVER plug 2 pin European plugs into 3 pin sockets without using a European adaptor plug.
  • Only use one socket extension lead per socket and never plug an extension lead into another extension lead.


Use this calculator to check if you’re exceeding the maximum load following the 13 amp rule.

Click “Get Started”.

The Socket Calculator has been brought to you by Electrical Safety First.

For more safety information visit


What To Do Next

Consider having additional sockets installed if you regularly rely on extension leads and adaptors – and use a registered electrician to carry out the installation work.

Overloading Danger Signs To Look Out For:

Fuses that blow or circuit-breakers that operate for no obvious reason.

Smell of burning plastic.

Sparks when connecting appliances

Blackness or scorch marks around a socket or plug, or on an appliance

Damaged Cables


PC’s vs Gaming Computers Power Consumption.

It is worth noting that standard home PC’s often come fitted with 450w or sometimes 350w power supply units (PSU’s). However if your PC is a higher spec machine, designed for gaming or other intensive tasks, it is likely that the computer has a much higher  PSU, possibly 750w or higher.

This must be taken into account when considering how your appliances are connected to the mains without overloading sockets or extension leads.

Electrical Appliances That Should Never Be Used On A Multi-Socket Extension

Here are a few appliances that should be connected directly into a wall socket and not via an adapter.

  • Kettles
  • Portable Heaters
  • Hair Dryers
  • Toasters
  • Fridges
  • Microwaves
  • Slow Cookers
  • Washing Machines / Tumble Driers
  • Dishwashing Machines

If it has a heating element – do not connect via a multi socket or adapter. 


Appliances That Can Be Connected To The Mains On A Multi-Way Adapter Extension

  • TV
  • Fan
  • Lamp
  • Router
  • Mobile Device Charger

There are too many t list but if in doubt – the advice from electricians is “do not overload sockets”. 



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