REPLACING AN OLD FLEX
The procedures for replacing an old flex on a standard lamp, table or desk light are virtually the same. They may have to be modified slightly depending on the design of the light.
Usually the flex is concealed within the fitting and has an out let point on the side near the bottom so that the base of the light can stand flat on the table or floor. Sometimes a standard lamp has feet so the flex can be taken under the base and then up the central column to the lampholder at the top. With a desk lamp, the lampholder and switch mechanism are fixed to a bracket which in turn is fixed to the metal cone shade with selftapping screws.
1. To remove the old flex, take out the bulb and take off the lampshade or cover. On table and standard lamps this is held in place by a screwdown ring or the skirt of the lampholder. On desk lamps unscrew the bracket from the cone and then ease down the lampholder so the flex connections are exposed. Unscrew the terminals to free the cores from the lampholder.
2, With standard and table lamps you need to unscrew the top half of the lampholder to get to the terminals. Do this by holding the top half and rotating the bottom section attached to the base unit. You may find it easier doing it this way round because the flex won’t twist and kink as much as you work.
3. Once the flex is free, you should be able to draw it back through the unit. But before you do this, tie some string or thin wire to the end of one of the flex cores so that it can be pulled through the lamp as the old flex is removed and then used to draw the new flex into the lamp.
Measure out the length of new flex you need. This may be two or three core depending on whether the lamp needs to be earthed. If the light has the original flex then use this as a guide — although with very old lights that have obsolete types of flex you should upgrade this anyway. As a general rule, if the lamp has any exposed metal parts then it should be earthed.
4. Draw the new flex up through the light fitting.
Use a bradawl to pierce a NM small hole through the flex very near to one end. Thread the draw wire or string through the hole and tie it back on itself. This makes a more secure fixing than if you just tied the wire or string round the top. It also means that the flex is less likely to catch as it is drawn round any bends along its path. On some lamps a draw wire may not be necessary and the ‘stiffness’ in the flex may be sufficient for it to be pushed through the base unit. And on some china lamp bases you may be able to remove the felt pad from the bottom so you can get your hand inside to feed up the flex to the lampholder.
5.Once the flex has been drawn through, cut off the end beyond the hole to release the draw wire. The insulation on the flex cores in all probability will have been damaged by the bradawl so this section must be discarded.
6.Next, prepare the ends using the old flex as a guide for the amount of insulation and sheathing to remove. Then secure the cores, including the earth, to the terminals. However, before doing this it’s worth checking to see if the cores need heat resisting sleeving.
Now screw the terminal housing and cover back together. With table and standard lamps, you may once again find it easier to rotate the base rather than the socket to prevent kinking the flex. Then fit the shade and the skirt that prevents you from touching metal parts of the socket while you’re changing a bulb.
On desk lamps you may have to fit the skirt before attaching the headgear to a bracket which in turn is screwed inside the metal shade.
At the other end of the flex fit a threepin plug with a 3 amp fuse (colour coded red).