What is the household AC electrical power service in the UK?

Answer 1

Answer for countries in Europe and other world areas running a 50 Hz supply service.Originally the UK mains supply voltage was specified at 240 volts AC or, more precisely, 240 volts RMS +/-6%. The alternating current runs at a frequency of 50 Hz.

Some time ago, to allow harmonisation across Europe, the specifications were changed to 230 volts RMS +10%/-6%, also running at a frequency of 50 Hz.

Thus the mains supply voltage will remain within European Union norms (standards) even if it varies between an upper limit of 253 volts and a lower limit of 216.2 volts.

A 240 volt 50 Hz appliance can have up to 3 wires altogether:

• one single 240 volt "live" or "hot" wire which colored brown;
• a neutral wire which is colored blue;
• a safety "earth" or "ground" wire which is colored green/yellow

  but this is not required if the appliance is of the type known as "double insulated".

The hot wire feeds alternating voltage from the power station to the load and, because the voltage is alternating, the load draws an alternating current. Then the neutral wire returns the current to the power station to complete the circuit.

Note

The United Kingdom and the Republic of Ireland (and some other countries elsewhere, most of which were formerly British colonies) use a power outlet plug and socket system which is totally different to the rest of Europe:

• All power socket outlets are rated at 13 amps to take a standard 13 amp plug.
• Each power socket has a protective insulated shutter that safely uncovers the live (or hot) and neutral holes when the plug of an appliance is inserted. The shutter immediately covers the holes over again when the plug is removed. The shutter is operated by the insertion of the earth (or ground) pin which is longer than the live and neutral pins.
• Each 13 amp plug has 3 rectangular (not round) pins for a brown live wire, a blue neutral wire and a green/yellow earth wire . There is also a fuse that should be selected to be of the right size to protect the appliance it is attached-to.
• The actual plug type is known internationally as Type 'G'.
• It was designed for use on any normal house mains voltage or frequency and is used in the UK and other countries which have adopted the UK mains power plug and socket system for appliances.

  It is a very good plug and socket system but not many other countries have adopted it - probably because they didn't invent it!

Outside the UK and The Republic of Ireland (Eire), European countries use plugs where all the pins are round. Sometimes (but not always - it depends on the country) the plug's earth connection is not a pin but is a ground-socket within the plug which connects to a ground-pin which permanently protrudes from within the wall receptacle. That arrangement of pins and pin-sockets makes it impossible to insert a non-grounded plug into the receptacle! Another common European plug - the "Schuko" - does not use any earth pin but instead uses two clips which are positioned diametrically opposite one another on the outside edge of the plug.