The electrical supply in the UK is 240V A.C. at 50 Hz, this is the same for most private premises in the United Kingdom. (Some industries, building sites and specialist premises may have different power supplies!)
Domestic appliances usually use the Western European wiring colour code of Brown=Live, Blue=Neutral, Green&Yellow=Earth. New appliances normally come with the plug attached. The maximum safe load on most wall sockets should be 13 Amp but it is prudent not to test the limits of old wiring.
 
Many Western European countries use mains power supplies that may be compatible with the UK system but an "adapter" will probaly be needed to make your plug fit into our sockets. Unfortunately, this is not the case for every country. Many places, (especially those with links to the American continent,) use a different (110V A.C. 60 Hz) mains supply. Trying to plug your 110V device into one of our sockets could risk electricution, burn out your gadget and damage the house wiring!
 

 
Here are some handy tips for visitors who know their devices are compatible with the UK supply...

• If your plug is different to ours but the device can accept 240V, it may be easier to get an adapter before you come, as opposed to trying to find one here. If caught out, try electrical suppliers and the larger discount stores. be aware that many low-cost adapters will not connect the earth pin! (Particularly true for "French" style European plugs {where earth pin sticks out from the socket.} )
  
• If you know exactly what you are doing, it MAY be possible to fit a UK plug to your gadget but any mistake could be costly or deadly.
  
• UK plugs normally contain a fuse, these fuses NEVER fail in normal use, if a fuse blows then something is wrong! It could be as simple as your are trying to run a 13A appliance via a 3A fuse but you must identify the problem before you replace a fuse.
• You may see a special 2-pin electrical socket inside bathrooms. This offers a low-current supply that is intended for electric shavers. It is unsuitable for most other appliances, and there is no earth connection and despite appearances, it is NOT designed for European two pin plugs! Some of these special sockets incorporate a 110V outlet that can power 110V shavers. It is very easy to overload this type of socklet.
  
  • The picture shows an EU 2 pin plug (left) and UK Shaver Plug (right)
  • These plugs are NOT the same - forcing the wrong plug into either socket could cause damage or safety problems
  • The pins on the EU plug are longer than those on the Shaver plug
  • The pins on the EU plug are narrower than those on the Shaver plug
  • The pins on the EU plug are further apart than those on the Shaver plug
• People in the building trade and industrial electricians may encounter other electrical supply voltages.
• There are special problems relating to TVs, Videos, DVD's and similar devices - if in doubt, seek advice before travel.
• If you are hiring a car, consider bringing the car adapter for your favourite gadget.
• Caravan sites often provide either blue 16A European power sockets or the UK 13A domestic socket but rarely both. If you are camping and need power, bring the appropriate adapters. (Many caravan sites will rent or sell the appropriate adapters for their supply.)

DigitalDan.co.uk