MANY houses lack sufficient lighting plugs and power points to allow for increased use of electrical appliances, and existing plug points may often be in inconvenient places.
If it is proposed to add another electric point a little previous planning and consideration will save time and confusion. First, what is the new point required for, lighting or power? Lighting includes here small apparatus such as electric irons, vacuum cleaners, small electric fires, standard lamps; anything that does not exceed 5 amp. Loading. Power (in the household) includes any apparatus with a loading in excess of 5 amp. But not exceeding 15 amp., such as electric motors, large electric fires, and so on. Such items as electric cookers may take considerably more current than that mentioned, but these are not considered here as they require an entirely separate installation.
There are varying sizes of plug points in houses, with both two or three-pin connections. The modern practice, however, is to standardize on 5 amp. Three-pin types for lighting, and 15 amp. Three-pin types for power, the third pin being used for earth connections. It is advisable to have all the plug points on the same circuit of the same type, so that all the appropriate household electrical appliances will readily fit into any socket (on the right circuit) in any room.
Second, at what point should the extension be commenced? The obvious answer seems to indicate the nearest ‘live’ plug point. But this section of the wiring may already be fully loaded, and should that be the case, the new extension may have to be taken back to the fuse box at the supply intake. The arrangements of the supply intake in dwelling houses include the company’s cable, sealing ends, cutouts or main fuses, and the meters. From this point the wiring contractor fixes a main switch fuse and any additional sub-fuse boxes that may be required for the various wiring circuits, the power and lighting circuits being in separate boxes.
The supply company does not forbid the running of extensions from the fuse box, providing it does not mean interfering with the mains supply connections. If the fuse boxes are erected the extension may be made by connecting into the sub-fuse box without interfering with the mains supply. In a well-planned installation the sub-fuse box will have one or two spare fuse-ways, to allow for future extensions, and, by switching off the supply at the fuse switch, the connection of the new extension can be carried out with safety. Before commencing any extensions or repair of any kind the supply must be switched off.
The procedure to adopt when carrying out an extension to the wiring is to cut off the current and install the wiring first. The supply shop will furnish the correct size and type of vulcanized India rubber-covered wires or tough rubber twin, if the purpose is clearly explained. If possible, it is advisable to carry this wiring under the floorboards, as this usually gives a more direct run to the supply point and cuts down the length of cable required, at the same time ensuring a neater job.
The socket is then fixed to the skirting board and the connections made. It is necessary that these connections should be tight, and no bare wire should be showing after they have been made. The last part of the operation is the connection to the fuse boxes. Plenty of wire should be allowed at this end, as one wire has to go to a top connection and will probably enter the fuse box from the top entry.
Before connecting, check to see that the main supply is switched off, then insert the wire end in the brass connector and screw down firmly. The fuses should then be made up with suitable fuse wire; 5 amp. For lighting, 15 amp. For power purposes. The extension is then complete and the supply may be switched on. If spare fuses are not available in the sub-fuse box it will be necessary to install a new fuse box, in which case it should have additional spare fuse-ways to allow for future extensions. This new fuse box will require a supply, and when all connections are made to the new wiring the supply company must be approached to make the necessary connections to the main supply.
Quite simple alterations to the existing wiring may be carried out with flexible leads and multi-way adapters. Flex is available in two-and three-core types, and when purchasing, it should be stated clearly for what purpose it is required; the size of wire, and the current carrying capacity being specified. The multi-way adapters are very useful, especially in a house which is wired for two-pin plugs only, making it possible to take several pieces of electrical apparatus from one plug-point without incurring any work on the ‘live’ side of the wiring.
There is, of course, a limit to the amount of flexible lead that can be taken from any one socket, and it should always be kept to a minimum. The trailing of long flex can prove dangerous when it is constantly walked on. It is as well to follow a strict procedure when dealing with an extension to, say, a standard lamp. Generally, a lamp of this description is movable to give additional light in any part of the room, hence a considerable length of flex may be necessary over and above that which is supplied with the standard lamp.
A piece of flex of the best quality should be obtained, with sufficient extra length allowed for making joints, plug connections and so on. Quality is important, as the flex will be used in a trailing position and may have to stand considerable wear; the better the quality the safer the job. In the case of a standard lamp it may not be possible to put a complete new flex from the switch to the plug point as the flex usually runs up the centre column of the lamp standard. If this is the case, a join will be necessary somewhere near the base, in a position where it will be subjected to as little wear as possible.
The join may be made by firmly twisting the ends together and covering with insulation tape, but a connector is better. Connectors usually take the form of a brass tube with screws at either end to clamp the wire in position, the whole connection being covered in a porcelain shroud. They can be obtained in single or double types for various sizes of wire .
When the cleaned wire ends have been inserted in the connector and the screws tightened, the whole join should be covered with insulation tape as far back as the braiding. Connection of the flex to the plug completes the work. The wire should be placed under the washer and in the direction of the tightening of the screw, so that when the screw is tightened the wire will tend to close into a loop, the result being a very sound connection. If put in the reverse way, the wire may come out from under the washer, a bad connection resulting.
Actual connection to the plug point can be made via a multi-way adapter, which will give facilities for supplying other apparatus from the same point without having to disconnect the standard lamp. A number of types of multi-way adaptors are on the market.
It is necessary to make certain that the adapter plug points make firm contact when inserted in the socket. If the plug is found to be on the slack side it should be removed from the socket and the split end of the plug point be gently splayed out by the insertion of a thin knife blade.
A wireless set should not be connected via a multi-way adapter, because it is almost impossible to get the necessary perfect connection with so many sliding contacts. Bad or indifferent contacts mean sparking, and this gives rise to crackling in the set. A wireless set should always be connected to one plug and socket to avoid that trouble. An electric clock is also better with a plug and socket to itself, for if an adapter is used there is a possibility that at some time the current to the clock may be interrupted by the connection of other apparatus to this point of supply.
It should be noted that, although there is no law or other regulation to prevent the house holder installing additional points, the supply company will not connect the wires to the main supply if the new wiring does not stand up to the insulation test standard required by that company. There must be nothing slipshod about it.