Check all walls for wires and pipes before cutting out for any new cables and boxes.
• Turn off the power and remove the fuse from any circuit you are working on.
• Make sure no-one can turn the power on by mistake.
• Use only approved materials.
An electrical supply will come to your home your home at a main, sealed fuse called a service head and from there will go to your meter via one large red and one large black wire. The meter measures how much electricity you use.
The amount of electricity available to you is measured in Volts, and the rate at which it flows along its conductors is measured in amps. The power required by any appliance is measured in Watts. the formula for working out the correct cable and fuse is; Watts divided by Volts equals Amps.Electricity flows along the live wire, feeding whatever is required and then returns along the neutral wire to its local transformer. The flow can be stopped by the insertion of a switch, which for all practical DIY purposes is placed in the live wire.
Switches, most often, will be linked from your ceiling rose through a separate cable, even though one of the wires in this cable is black it is still live.
Switches, most often, will be linked from your ceiling rose through a separate cable, even though one of the wires in this cable is black it is still live.
Electricity will always find the shortest or easiest route and you may represent it, so be careful.
Cables
Fixed wiring is done in cable. This consists of individual conductors (wires) sheathed separately, by insulation to prevent leakage. The earth or "ground" wire is normally bare. The wires are then jointly covered by the outer sheath. The wires are colour coded, red for live, black for neutral and green/yellow striped for earth, where this is covered. Modern cables are sheathed with PVC which has an indefinite life, older cables were rubber with about 20/30 years life. If your home has these cables do not attempt electrical extensions with them. When installed, bare earth wires should be covered with an "earth sleeve" which can be bought in all sizes at an electrical store or most diy stores.
1.5mm is most common in lighting circuits. When installed it must not exceed 110m in length and carries a fuse rating of 5amps. (6 amps if used in conjunction with a miniature circuit breaker). It is acceptable to run 1200 Watts on this cable, the equivalent of 12 x 100 Watt bulbs, but lighting circuits are normally run independently on each floor of your house.
1.5mm is most common in lighting circuits. When installed it must not exceed 110m in length and carries a fuse rating of 5amps. (6 amps if used in conjunction with a miniature circuit breaker). It is acceptable to run 1200 Watts on this cable, the equivalent of 12 x 100 Watt bulbs, but lighting circuits are normally run independently on each floor of your house. 2.5mm (as above but larger) is usually used for the installation of power sockets on a ring main. The circuit uses a 30 amp fuse at the consumer unit (32 with a MCB). Cable length must not exceed 60m or 50m with an MCB.
Three core and earth is used to interconnect switches with more than one operation.
Flex, is simply flexible cable and is used for connecting appliances. The colour coding is different using brown for live, blue for neutral and green/yellow stripes for earth.
There are many more cables for connecting cookers etc, but these are generally run directly from the consumer unit and require a professional electrician for their installation.
Fuses
Fuses are placed into a circuit as a deliberate weak point. If anything goes wrong within your circuit, the fuse will "blow" first. With the modern RCD boxes, the trip switch will go. BUT BEFORE YOU PUSH IT BACK ON, LOCATE THE REASON WHY IT TRIPPED. Most of the time it is because the circuit has been overloaded or there is an earth fault. If you are in doubt
contact an electrician.
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