Sorting out the Loop Light

anotheruser

Here we go then.



I have two lights, two switches. Both switches operate both lights together. One light is in dining room, the other living room. The rooms are partly joined together.

The light in the dining area was an easy straight swap. Earth, Live, Neutral. It looks (but can't be certain) that those wires head towards the other light fitting.

The living room light fitting has four grey wires going into it.
Each of those has a neutral, earth and live. See the photo (yeah I know it's manky!).

1) Is there a way to reconfigure these wires so the switches in each room ONLY work the light in that room?

I'm guessing yes but it'll be a bit strange as I guess the switch on the dining room comes to the living room light fitting and would have to stay that way. Reason being is that I don't really want to be digging up floorboards or whatever finding out what's going on.

2) Is there an easy way to check which of the grey wires is coming from where or going to where?

And finally...

3) Why do I have four grey wires coming into this light switch?
I would have thought I have one from the switch to the light, one from the other switch to the light and one from light to light. What is the other one?

Ectophile

1. It's impossible to say without fathoming out what wires go where.

2. If they aren't labelled, then the only way is going to be to "buzz it out" using a continuity tester.

3. There must be an incoming live and neutral somewhere. One possibility would be (i) incoming mains, (ii) drop wire to 1st switch, (iii) drop wire to 2nd switch, (iv) wire to other light. However another possibility would be (i) incoming mains, (ii) outgoing mains to other lights in the home, (iii) drop wire to both switches, (iv) wire to other light. Again, there's no easy way to tell without buzzing it out.

TheCyclingProgrammer

You're making the common mistake of assuming each black wire is neutral. They aren't all neutrals.

In your picture, the rose has three terminal blocks. The top one is neutral. The middle one is permanent live. The bottom one is switched live.

One of the incoming wires has to be the loop in from the main lighting circuit. There may also be a loop out to the next light on the circuit unless this is the last one. There must be a connection to at least one of the switches and also to the dining room light.

You should be able to identify the switch drop as this will have a red wire (live) connected to the middle terminal and a black wire (which should really be sleeved red or brown) connected to the switch live terminal.

I can see a red wire connected to the switch live - if this cable also has a black connected to the neutral block this probably will be the switched supply to the dining room light. You can easily confirm that by disconnecting it.

Anything connected to the live and neutral terminals is probably part of the lighting loop circuit.

I suspect what you've got is loop in, loop out, switch drop and feed to the dining room light. If you check both switches you should find one has two cables - one from the ceiling rose and one to the other switch. The same as this diagram but with the addition of the dining room light connection.

https://www.diynot.com/wiki/efa6e2d8354dac4a6228ec42fb0b6500

TheCyclingProgrammer

To answer your question about having each switch work each light independently, for this to work you effectively need two separate switch live terminals one to connect the dining room feed to and one to supply the living room light. Right now you've only got one.

Unfortunately if I'm right about your wiring setup, there's no way of achieving this with out some disruption and dropping a new switch cable. This is because you only one switched supply cable to from the rose to the switches. It doesn't matter what you do at the switch end, you're only ever going to have one switch live coming back to the ceiling rose.

What you really need to do is take a permanent live instead of a switched live from the living room rose to the dining room light, put a new switch drop from the dining room light to the dining room switch, disconnect and safely terminate the cable between the switches and rewire the living room switch as a normal one way switch.

TheCyclingProgrammer

I should add of course that Ectophile is quite right when he says that these are only assumptions and that the wires need to be tested to correctly establish what they are. If you're not confident in what you're doing then get an electrician in.