Identify the cables
Switch off the power supply at the consumer unit and remove the fuse for the circuit.
Unscrew the ceiling rose cover and examine and identify all the cables.
Light switch cable
Firstly, identify the switch cable. This will have its brown (old cable colour = red) conductor attached to the live terminal, and its blue (old cable colour = black) conductor – which should have been tagged with brown (old tag colour = red) because it is the switch return conductor – attached to the live flex terminal. This same terminal will have the brown (live) of the flex going to the light itself.
junction type ceiling roseIf there is no switch cable here, then it will have been switched via a junction box system in the lighting circuit above.
Label the cables once they have been correctly identified.
Other light circuit cables
All other cables should have a brown to the live terminal block, and a blue to the neutral terminal block. These are all part of the lighting supply circuit.
All cables will also have a green and yellow sleeved earth connected to the earth terminal.
If your ceiling rose houses cabling which you are unable to identify, or differs from this description, or has no earth conductor, seek the services of a professional electrician.
Identify and label each of the cables and the two switch conductors (if it is switched at the rose), then disconnect each conductor from its terminal.
Note the location of the flex connections of the light fitting before releasing them. The brown, live, will be on the outermost terminal next to the conductor coming back from the switch – the blue one tagged with brown. The blue, neutral, will be on the other outermost terminal next to the blue, neutral(s), in the neutral terminal.
Unscrew the ceiling rose and ease it over the cables.
Prepare the new ceiling rose
Take the new rose, undo its back piece, and tap out the blanking plate(s) on the back to allow sufficient space for re-threading the cables. To prevent damage to the cable, smooth any sharp edges with a file. Feed the cables through and fasten the rose to the ceiling with screws. If there is insufficient fixing, you may need to fit a wooden mounting block between the joists above.
Reconnecting the cables
Reconnect the conductors in exactly the same way as they were before removal.
Feed the new rose cover over the flex for the light and reconnect the flex to the outer terminals in the same way as before. Double check that all your connections are to the correct terminals and all are secure with no exposed conductor showing.
Once you are sure that all work has been completed correctly, replace the fuse for the circuit, switch the power back on, and test.