Advice in moving a light switch

3 Jul 2012
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United Kingdom

I am in the process of partitioning a room so that the open plan living room and dining room become separate.

In the living room there is a three gang light switch controlling Living Room Ceiling Light, Two Wall Lamps and a Dining Room Ceiling Light.

I have taken a picture of the light switch in that order from Left to Right.

I already have a route for the new cable and have traced all of the existing cables. The intention is to remove the Two Wall Lamps and have a single gang switch for the Living Room Ceiling Light and then relocate the cable for the dining room switch so that it is also on a single gang switch for the Dining Room Light.

I was surprised to only find two cables running to the switch when we have three switches (as above) and this spaghetti junction of cables in the attic.

I have identified them all as:

I - Dining Room Light
II - Living Room 3 Gang Light Switch
III - Wall Lights (to be removed)
IIII - Living Room Light
IIIII - Kitchen (I think)
IIIIII - Hall (I think)
IIIIIII - Source/Feed (I think)
OLS - Outside Light Switch
OL - Outside Light

I am confident with all manner of DIY and wouldn't attempt anything that I am not sure about, hence the question. I understand basic lighting circuits but this I am struggling to work out.

All I wanted to do was have a separate switch for the dining room light.

I hope someone can help.


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The switch wiring is fairly standard. There is a live supply which is linked to all three COM terminals, then a switched live out to each light from the three L2 terminals.

So you need to disconnect the existing switched live going to the dining room light at both ends, isolate it to make it safe. (I usually put an insulated screw connector on each end and tuck them out of the way)

Then run a new cable from the attic junction box to the new location for the dining room light switch. I have made a sketch for you below. Earths are omitted for clarity, but should be sleeved and connected. For simplicity I have shown the old wiring colours for the new cable.

Alternatively, if you wish to make the connection to the existing switch, the same thing could be achieved as follows. Put the new screw connector inside the existing switch backbox. The first option would be tidier in my opinion though, it keeps the wiring in line with the existing pattern, and terminations would be simpler if you are inexperienced with regard to working with connections within a small space.

For the moment, to keep it simple, I've left the wall lights as they are, once you have the dining room part sorted, if you need any further assistance with removing the wall lights, or replacing the three gang switch with a single gang, post back.
Thank you Stem,

That is an incredibly helpful reply and the diagrams make it very straightforward to understand.

In fact, when it comes to removing the wall lights I was just going to trace the connections and remove the wires. This would then leave me with one cable to the Living Room so that I could install a 1 Gang switch and then I'd already have the Dining Room 1 Gang switch.

I hadn't looked into this as such yet but I was assuming this would be simple. Or have I assumed wrong?


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Pretty much, but if you are going to actually remove the cable with the wall light switched live in it, you will have to check what the other wire in the same cable is for, because it may still be in use.

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