Old wiring to new spotlights with 1 L N E

20 Dec 2022
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United Kingdom
I'm trying to wire to sets of downlights to an existing double dimmer in the living room.

I pulled down the light fixture nearest the switch to reveal the wires in the attached picture.

I've traced back the cables as far as I can and labeled them.

The label "to next night" feeds across to the next light fixture in the same room and a separate switch cable feeds from the dimmer to the next light.

"Switch" feeds to a 2 way 2 gang dimmer fixture.

"Light to junction box" feeds to what appears to be a junction box that's a bit out of reach but I could see with a torch.

"Mains" feeds into next room.

How would I remove the 2 light fixtures and rewire the 2 sets of downlights to the 2 dimmers?

Thanks for any help

The spotlights are 1 earth, live, neutral. Loop in/out.

How do I


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Are these LED downlight? Is your dimmer compatible? Do your downlighter have a load / supply set of terminals. If so its easier to use those.
I think I can get my head around that. What made it a bit confusing initially to me is the use of 2 red cores to the actual lamp (bulb), the live (line) side sleeved with black to identify it as the switched line doesn't seem necessary to me, I would have thought the neutral would be better sleeved black. In fact that bit of red neutral could be got rid of entirely it seems. But hey, it's only colours.

So just to confirm, only one dimmer does this lamp? And the switch cable from the other dimmer goes to a similar job on the other fixture in the room?

And your new fitting has earth and loop in/out terminals as well as neutral and switched line?

If so, in an ideal world you could do away with the chocky blocks but whether that is practical with 3 lives, 3 neutrals, 4 earths and a switched live would depend on how well sized the terminals are on the new fitting. It would be doable with a modern pendant but it might be best if you show a picture of the new fitting.
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The downlights are led.
The dimmer was already installed for the previous light which is halogen. So not 100%.
The downlights are integrated units. So the transformer/driver is built into the led.

Yes only 1 switch cable to this lamp.
A separate switch cable runs from the dimmer to the other lamp in this room.
Yes the led has 2 connectors for each of the earth, live and neutral for the loop in and out


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The first thing would be to purchase a decent junction box and terminate the incoming Feed., such as the one below.


Connect all the black neutral wires together with exception of the switch black - which as mentioned becomes a switched live. This needs to be sleeved in Red for the 16th Edition insulation colour version. Connect all sleeved earths together.

Connect the Red going to the switch to the mains red.

Mark the black cable "coming back" from the switch with some Red sleeve to denote it being as switched live (as mentioned to avoid confusion)- this connects to both light Lives and the blacks back from the lights terminate into the neutral to provide the circuit for them to work when the switch is turned on. Does that make sense?

You need to remake all those connections in a junction box ,and if it's not going to be accessible in the future a maintenance free one should be used.
All you need to take to your new light/s is switched line ,neutral and earth.
After a bit of fiddling. This work with the switch. The 2nd light fixture is still the old fitting and also works with the switch.
Is this correct?
How would I connect the 2nd set of light?
Would I need a 2nd junction box to connect the cables from "to the next light" and the switch cable then to the 2nd set of downlights?



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If I have correctly understood your intentions ,you propose to have another set of lights ,connected to their own switch, totally independent of what you have already done so far. If so you need to replicate what you have done, at the new position, and install a switch cable and switch.
Earth sleeving needs to be put on the bare earth conductors. Two reds are inserted into L1 they can go into separate ports - move one up a notch as they'll still be connected and the block isn't designed to take two cables into the same termination point

Sort of. The original lights were set onto a double dimmer and all the connections to the junction box shown were in choc blocks to the original light.

The old fixture has the cable labelled "to the next light" with an earth and neutral. Then a separate wire with only a live goes from the dimmer to the next light.

I want to make use of the existing dimmer and have 2 sets of led downlights with a switch for each.

I've connected to old wires now to the other LEDs and now they work but the original lights which worked before I made the 2nd lights connection is no longer switching on
Sorry ,I can't get my head around what you are trying to explain.
In your diagram you have one cable marked " new cable to downlight" and I assume that feeds however many light fittings you desire to be operated from the switch that is wired into your new junction box.
You now want to have another set of light fittings connected to a second switch ,if so ,where is the switched live cable from the second switch ?
The original lights were 2 lights controlled via double dimmer. 1 switch per light.
They were joined together using choc block above the 1st light.
The cable labeled "to the next light" fed from the 1st light to the 2nd. This cable is a black and earth.
There is another cable from the dimmer switch that fed to the 2nd light. This is a single core switched live.

The junction box that I've worked up is the same connections as the previous connections but I added a new cable to connect to the 1st set of downlight that would correspond with the 1st switch.

I connected to 2nd set of downlights to the original cable labelled "to the next light" and the original single switch cable that was connected to the old 2nd light

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