How do you install a ring main and how does it work?

Answer 1

Installing ring main circuits is what qualified licensed electricians do. To become licensed they have had to complete a lot of training and pass exams. All this helps to ensure that the work they do will be done safely and efficiently.

• In the UK - and maybe in other countries too - a "ring main" is the name given to what is literally a closed ring of cable installed at a property to supply current to the power sockets. (Power receptacles in US parlance.)
• If a ring main circuit was not used then a separate dedicated breaker and "spur" length of cable would have to be used to supply every small block of sockets, a "block" being, say, for a room or pair of rooms.
• A ring main circuit is preferred compared to the older idea of many separate cable spurs - using spurs is also known as a "star" layout - because, in general, a thinner cross-section cable can be used to connect many sockets distributed around a closed ring circuit compared to the size of cable that would have to be used for the longest spurs in a star layout. A star layout also needs a much larger number of separate breakers, one for each spur.
• A ring main circuit always starts and finishes at a dedicated breaker on the main consumer panel. The cable forming a ring main circuit always has three wires: live, neutral and earth. (Hot, neutral and ground in US parlance.) An office or factory would probably have many separate ring main circuits.
• In a typical domestic house wiring system there would be a dedicated breaker and ring main circuit for all the power sockets on each separate floor. An additional breaker and ring main circuit might also be installed to feed all the kitchen's power sockets but the cooker (range in US parlance) would usually have its own dedicated spur cable fed by its own circuit breaker. Similarly the house's boiler (= furnace) - and any other high-power-demand appliances such as 10 kWatt electric showers - would each have their own breaker and spur. (So the "star" cable layout still survives even though ring mains are great for all the rest of the power sockets around a house!)

The UK and Republic of Ireland 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: a live, a neutral and an earth pin. 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!

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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.