Light wiring diagrams
Ceiling rose wiring diagrams are useful to help understand how modern lighting circuits are wired.
|Before working on any electrical circuit you must ensure that it is isolated correctly and cannot accidentally be switched back on. Please read the article on safe isolation procedures before doing any electrical work. If you are not 100% certain what you are doing call a qualified electrician. Building regulations are changing all the time and modifying your home electrics could be against new rules and could invalidate your home insurance, if in doubt check first!|
These are only schematic diagrams to explain about the different kinds of arrangements that you may find when changing a light fitting. The earth wires have been omitted for clarity and would need to be connected at all switches and ceiling roses. The wires would also be covered by the protective outer sheath (cable).
This is a diagram of a ceiling rose using the old colours where Live is red and Neutral is black.
The earth wires have been omitted for clarity, but must be connected!
Hopefully this will make it clearer as to what the wires at the ceiling rose are for. You can see that there is a Live and a neutral that has come from either the consumer unit or from another light fitting. Then a live and neutral that goes to the next light fitting, which will probably be in the next room. Then a wire goes from the live terminal and to the switch, A wire then goes from the switch to the switched live terminal on the ceiling rose. The switched live wire may be completely red, have a piece of red sleeving over it or may be wrapped with red tape, or non of the above. If it is not identified then it should be wrapped with red insulation tape. The Lamp is wired so that the neutral black wire is connected to the neutral terminal and the live red wire is connected to the switched live terminal.
To complicate matters further someone may have decided to add another light, perhaps wall lights somewhere and has taken a feed from your ceiling rose. Now the ceiling rose would start to look really busy and would have an extra live and neutral (+earth).
You may find that there are only a few wires in your ceiling rose. If this is the case then it is either the last light on a loop in circuit or the connections could of been made in a junction box and then a single cable has been run to the ceiling rose or the lights could of been wired with the neutral wire in the switch (instead of being in the ceiling rose)
This is an alternative way of wiring a lighting circuit. Instead of taking the feed wire from the consumer unit to the ceiling rose it is taken to the switch. The permanent live wire is wired into the switch and the switched live into the switched live terminal. The neutrals are connected together using a terminal connector. You can also see that another live and neutral wire go to the next light switch.