Light circuits are generally installed using 1.0 mm² or 1.5 mm² Twin & Earth cable. The picture shown below is a typical wiring diagram for a lighting circuit by today's standards. There are, of course, variations eg, older wiring may not include an earth conductor or the earth may be the steel conduit that the conducts are placed in. The represented switch is a two way light switch wired as a one way. You may find additional conductors if the light is being controlled from more than one location. Furthermore use caution when working on these circuits as it has been found that they have been wired incorrectly or there is no Red Sleeving or Red PVC Tape fitted to identify the Live conductors. All earth conductors must be identified using Green/Yellow Sleeving. Some older installations will be using Green Sleeving to identify earth which was acceptable at the time. REMEMBER, before working on circuits previously energised, ensure Safe Isolation
OLD COLOURS
.
Click image to enlarge
(It will open in a new window)
REMEMBER GREEN REPRESENTS GREEN/YELLOW CONDUCTOR IDENTIFICATION
NEW COLOURS
.
Click image to enlarge
(It will open in a new window)
REMEMBER GREEN REPRESENTS GREEN/YELLOW CONDUCTOR IDENTIFICATION
Before replacing the light fitting, be sure to safely isolate the circuit (See Safe Isolation).
If there is no form of earthing in the lighting circuit and the light accessory requires one, you must install it.
If the light accessory is to be installed in the bathroom it must be included with the supplementary bonding. If there is no earth conductor between the light switch and the light fitting one must be installed either using a 1 mm² or 1.5 mm² conductor. Connect the earth terminal in either the switch or in the light fitting with 4 mm² and connect the other end to some part of the supplementary bonding already in place (See bathrooms). If the light circuit in the bathroom is not to be included with the supplementary bonding, because it falls outside the bathroom zones,or is exterior to the bathroom, then you must connect your earth to another available circuit or install one back to the fuse board.
If the earthing is by means of steel conduit, you must in some way connect your earth terminal from the light fitting to the steel conduit. Any electrical connections must be accessible and in an enclosure. Fully enclosed light fitting will count as an enclosure. If the light fitting is being placed over an existing conduit box, then the conduit box will count as an enclosure. Connections MUST NOT be pushed into ceiling voids. Ensure that the connector blocks that you use are of a suitable size for the fuse rating of the circuit.
Two way light circuits are used to control, say a landing light, from two different locations. The switches must be 2 way and they are connected together using either using 1.00 mm² of 1.5 mm² 3 Core & Earth. All live conductors must be marked using either Red Sleeving or Red PVC as indicated in the drawing below. All earth conductors must be identified using Green/Yellow Sleeving.
OLD COLOURS
Click image to enlarge
(It will open in a new window)
REMEMBER GREEN REPRESENTS GREEN/YELLOW CONDUCTOR IDENTIFICATION
NEW COLOURS
Click image to enlarge
(It will open in a new window)
REMEMBER GREEN REPRESENTS GREEN/YELLOW CONDUCTOR IDENTIFICATION
It is also possible to control a light or group of lights from several locations. This is done in much th the same way as a two way lighting circuit but with the addition of intermidiate switches between the two way light switches. By operating any of the designated light switches, the connected light or group of lights will be operated.
OLD COLOURS
Click image to enlarge
(It will open in a new window)
REMEMBER GREEN REPRESENTS GREEN/YELLOW CONDUCTOR IDENTIFICATION
NEW COLOURS
Click image to enlarge
(It will open in a new window)
REMEMBER GREEN REPRESENTS GREEN/YELLOW CONDUCTOR IDENTIFICATION
