Installing Extra Power Sockets at Focus

Fitting coving

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Extra power sockets allow you to enjoy using things like home computers, video recorders and TV sets without the irritation (and very real dangers) of long extension cables and overloaded adaptor sockets. Adding them yourself doesn't have to be difficult, dangerous or even very messy - provided you go about it systematically and follow the rules.

Socket outlets come in two basic kinds - flush mounted and surface mounted. Surface mounted look bulkier, but are really easy to fix - especially when used with neat, plastic conduit (or "mini-trunking"). Both kinds can be single or double.

This small leaflet is intended as a basic guide only. Many of the products for this project will include manufacturers instructions. These instructions should be followed to ensure best results.

Always consider 'safety' before you start any DIY project. Look for the 'Be Safe' sign and read the safety advice.

Essentials:
All available at your local FOCUS store

Protective eye goggles
Wire, pipe and power detector
Joist and stud detector
Plug-in socket tester
Green and yellow sheathing for earth wires
Spirit level
Wire strippers and a sharp knife
Rubber grommets and cable clips
A single, double or treble 13 amp outlet for each new power point
2.5mm2 "twin and earth" cable
For flush mounting
Hammer, chisel and bolster *
Drill and masonry bit *
Ready-mixed plaster
For surface mounting
Plastic ducting and impact adhesive or self adhesive ducting
Junior hacksaw

* Warning, care must be taken with these items

Preparation

Be safe. If the sockets in your home are old ones that come in different shapes and sizes, or if the cables that connect them look old and brittle, leave the job to a professional electrician - and preferably have all your wiring checked for safety.

The first thing you need to know is how the wiring in your house is laid out. It will consist of a number of circuits, each controlled by a fuse or a Miniature Circuit Breaker (mcb) at the fuse board (or "consumer unit").

There are two types of circuit: radial and ring.

Radial circuits.
Sometimes a radial circuit supplies a number of power points. You can add extra power points here - but only by adding them on to the last outlet in the circuit, and only if the total floor area served is less than 20 sq metres.

Ring circuits. With a ring circuit, the run of cable begins and ends at the consumer unit, and it can have 13amp outlets, provided the total floor area they serve is less than 100 sq metres.

Any outlet on the ring circuit can be used as the jumping-off point for a "spur" - which is like a little radial circuit. You can "tee" a new spur from an outlet that hasn't got one already, or you can add an outlet to the end of a spur - provided there are no more spur-outlets in total than the number of outlets on the ring circuit itself, and you stay within the 100 sq metre floor area limit. Sockets should not be fitted in bathrooms.

Work sequence

	1 Switch off the power at the consumer unit, remove the appropriate fuse cartridge, and switch the power back on. 2 Some consumer units have Miniature Circuit Breakers (mcbs) instead of fuses. These have a switch that turns off the power for that circuit. 3 Check that all the sockets in the room you'll be working in are no longer "live" using a Plug in Socket Tester. 4 Once you've disabled all of the sockets in the room, you need to work out how they're connected. Remove the face-plate of each socket in turn and see what the wiring behind looks like. If the socket is on a ring main, or part of a "radial" wiring system, there will be 2 cables going into the back, each of which has one red wire (live), one black (neutral) and one green and yellow (earth). 5 If there is only one cable, then you have either come to the end of a "spur", or the end of a radial main. 6 If there are three cables, the outlet is the branch-point for a "spur" - you can't attach any more cables here. 7 If necessary, examine more sockets until you can see exactly how your wiring system is put together, then choose a suitable outlet to supply power to your new outlet - referring to the rules given under "preparation". 8 Decide where to locate your new outlet. It should be at least 150mm above floor or worktop level. Mark its position, using a spirit-level to get it straight.
	9 Surface-mounted outlets These are easiest to fit - especially if the outlet you're drawing power from is itself surface mounted. Plastic "mini-trunking" conduit protects the cable and looks neat.
	10 Fix conduit and back box to the wall. Ensure that the 2 brass screw holes in the back box are horizontal. Check with a spirit level. 11 Knock out the appropriate cable entry section of the back box. 12 Cut the cable to length, allowing a good 200mm spare for making connections, then feed it into the conduit. Make sure there are no kinks or twists, and bring the ends through into the back boxes of both outlets before stripping ends and connecting. Snap-fit the conduit covers into place.
	13 Flush mounted outlets These take a little more work, but look considerably neater.
	14 When you have decided where the outlet will go and marked its position, work out the route for the connecting cable to follow. Eventually, the cable will be invisible - so don't put it where someone could drive nails into it accidentally, e.g. not diagonally across the wall: take it along the top of the skirting board and then straight up to the new socket. If installing on a cavity wall ignore points 15, 16 and 17.