Lighting Circuit

[Sapper]

Hi

I'm currently renovating a house and want to change the lighting in the kitchen from a pendant-style bulb to downlighters.

The problem is, the DIY books I own assume the lighting circuits use twin-core-and-earth whereas my lighting circuit currently uses single-core PVC wiring.(The circuit is not currently earthed but I'm going to fix that).

I've seen previous postings referring here to this type of wiring with two red wires leading to the light switch, but some of my light switches have three red wires. I think the third wire is connected to the next switch in the circuit...

What is going on here? I want to make sure I know what each wire is doing before I go messing with them. Do I need to get a pro in?

 

[plugwash]

note that singles should be kept in conduit for thier entrie run which is likely to be impractical with many types of fitting

frankly once you have opened things up enough to add earths it is probablly going to be easier for you to rewire the lights with T&E in the current normal way

unlike when wiring with T&E cable with singles there is no real reason to take the permanent live via the light fitting it can just go stright from switch to switch

 

[fubar]

I think the third wire is connected to the next switch in the circuit...

I believe this (loop-in at the switch) was very common wiring practice in Ireland in the 80s and 90s. You can confirm this by checking what you have at the ceiling rose. You'll need a test screwdriver or (better) a multimeter. I'd expect you to have a black (neutral) and a red (switched phase) and possibly an earth. Test that the red is energised only when the switch is closed.

want to make sure I know what each wire is doing before I go messing with them. Do I need to get a pro in?

You are probably the best judge of that. Do you understand how the wiring works and what you are doing? If not, get a pro in.

--
Michael

 

[fubar]

note that singles should be kept in conduit for thier entrie run which is likely to be impractical with many types of fitting

The way round this is to use 6241Y or 6241B single core and earth cable. They are quite hard to find in the UK now and are becoming more difficult to find in Ireland too, I understand.

Arguably the "loop-in at switch" design is safer that "loop-in at rose" (just see the number of clueless people on this board who tried to connect all reds together and all blacks together at the rose, only to get a big bang), but is more time consuming and expensive to install.

--
Michael

 

[Sapper]

Thanks both,

The single core cables aren't in conduits - its a bungalow they are going all over the place up in the attic. It would be nice to have it all squared away just like it is in my nice DIY books...

When I'm working on the electrics I try and do it bit-by-bit ie. I label everything and just repeat what has been done before as much as possible, test it, and if it works go on to the next bit - its worked for me so far!

I was hoping to be able to replace the current circuit with T&E one light at a time, but am I right in saying it would be much easier to take it all out and rewire completely?

But if this was indeed the norm in the 80s and 90s, would I be okay to leave it as is? Should I be worried about the fact that its not earthed?

 

[fubar]

I was hoping to be able to replace the current circuit with T&E one light at a time, but am I right in saying it would be much easier to take it all out and rewire completely?

That depends on how long the loop-in strappers are between each light switch and whether they run up the wall, over the ceiling and back down again or stay in the wall all the way. Either way, you will need to start at the first light in the chain and work forwards - you will find it hard to just do them randomly as you decorate each room. Replacing the singles with single&earth could be done a room at a time as long as you remember that the earth will not be complete until all the rooms are done.

But if this was indeed the norm in the 80s and 90s, would I be okay to leave it as is? Should I be worried about the fact that its not earthed?

You should sort out the earthing, especially if some of your fittings require an earth connection. You will probably want to work out whether it is going to be easier to replace what is there with single-core & earth or rewire with twin&earth. Either is okay AFAICT.

--
Michael

 

[Sapper]

Replacing the singles with single&earth could be done a room at a time

When you say the above do you mean that I could replace each of the 3 single wires connected to the light switch with single and earth? Does that mean I would have connect each of the 3 earth conductors to the earth terminal on the switch?

Thanks a million for your help...

 

[breezer]

if you can get single and earth , you will also need green/yellow sleaving then yes