Ceiling rose with 3* single cores

[kneelo]

Hello,

I had the floor boards up today and noticed that the ceiling rose for the room below, was wired with 3 singles. Probably the whole house is like this, this is just the first one I've seen.

The house is a 1970's house so quite old with regard to the wiring, but I'm really curious what type of wiring method for the lights would make this work with only 3 single core cables going into it.

Assuming one goes to the switch, would it be a neutral in and neutral out and the third is the switched live? I would guess in that case the permanent live is only going as far as the switch.

So if that is the case, the neutral is doing the rounds via all the ceiling roses, and the live is doing the rounds via all the switches, all in separate single cores. And no earth at all?

The reason I'm so curious is that I thought I knew (or had a decent idea) about how lighting circuits are wired, but maybe only by modern standards. This one got me thinking.

Thanks in advance,
Neil

 

[westward10]

Can you show a pic.

 

[kneelo]

Can you show a pic.

I don't have anything that would be useful, simply 3 single cores going into the rose. It was also obstructed by the joist so I couldn't actually see much, other than the fact they are single core.

From the direction they're going, one comes from the CU, another goes off to another room, and the third is chased into the wall below, where the switch is.

 

[brianmoooore]

Are the cables coloured grey along their length?

 

[Lucien Nunes]

So if that is the case, the neutral is doing the rounds via all the ceiling roses, and the live is doing the rounds via all the switches, all in separate single cores. And no earth at all?

Yes, that's about it. It was one of the ideas that stuck around for a while but never became the standard way of doing things. There was an earthed version too using single & earth, which you can still get.

 

[kneelo]

Yes, that's about it. It was one of the ideas that stuck around for a while but never became the standard way of doing things. There was an earthed version too using single & earth, which you can still get.

Thanks Lucien for satisfying my curiosity

 

[brianmoooore]

An earth wire has been required to be present at every lamp fitting and switch since 1966, so if the house was built in the '70's and none is present, it has been unsatisfactory from the start and will fail an EICR with a C2 classification.

 

[kneelo]

An earth wire has been required to be present at every lamp fitting and switch since 1966, so if the house was built in the '70's and none is present, it has been unsatisfactory from the start and will fail an EICR with a C2 classification.

I'm in Ireland, not sure the same regs apply. I think EICRs are UK only, right?

Although there are 3 metallic light fittings down stairs and there a more earths in the CU than earth carrying circuits so my guess would be that there are single core earths run to those lights. But I've never removed them so I can't be sure.

 

[MJPD29]

Yes, that's about it. It was one of the ideas that stuck around for a while but never became the standard way of doing things. There was an earthed version too using single & earth, which you can still get.

Single pvc/pvc and single and earth still very common here and in use In domestic setting