Help! Ceiling Rose with three cables.

[Codebyter]

I have just messed up , I am replacing a damaged ceiling rose on a bedroom light (damaged when moving furniture).

Unfortunately, I did not make a note of which cables were wired where in the old one. There are three cables coming into the Rose, each with standard Red/Black/Earth wires.

I am familiar with two cable setups, but haven't dealt with one of these before. Can anyone offer any way of figuring what the connections should be?

For information, as far as I can recall the wires to the bulb holder were connected to the two terminal block and the end three terminal block and all the terminal blocks were filled.

 

[alexnic]

What you have is a loop-feed circuit, one of the cables will go to the switch so you have to determine which one it is.

Get a meter and cut the power to the lighting, set the meter to read resistance then put the meter leads accross the red and black of each of the cables, they should be open circuit (no reading on the meter) then flick the switch to on (power still off) and check again. One of the cables should now be showing a closed circuit and this will be your switch wire.

Once identified, put a bit of red tape round the black wire as this will be the switchwire.

. Connect all the reds together in the (centre) terminal of the new ceiling rose,
. Put yellow/green sleeving on the earth wires and terminate these together in the larger brass terminal in the ceiling rose.
. Connect the 2-blacks together in one of the other terminals (neutrals)
. The other black cable with the red tape (switchwire) is then connected in the last terminal.

The lamp is connected accross the switchwire and neutral (black cables)

 

[Codebyter]

Thanks, That sorted it.