Celing rose conformation of wiring please

[kevsterdiy]

Hi

Today I have been helping my uncle strip his front room to have his plaster re skimmed, we took down the ceiling roses making note of the wires to go back later. After working on and having seen both loop-in systems and junction box systems I'm not entirely sure what he has.

It's no major problem because the roses/light will go back as it was but I'm curious to what it is. The house is about 1965 with no earth on the lighting (one circuit). In the rose it has two twin cables, containing black and red in each as you would expect, 1mmsq. All is original and not identified in any way ie red/black Switched Live tag.

We have;
Two reds are joined in one terminal (Live, these end here)
One of the blacks goes to one terminal (which in turn is blue flex/Neutral to bulb)
The other black to the remaining terminal (which in turn is the brown flex/L to bulb)
I need confirmation that one of the two cables is likely from a junction box on the lighting circuit, obviously one of the joined lives runs to the switch and returns as a switched live (brown on flex). In effect a continuous in-line switch and bulb?

I hope that makes sense - hard to explain in typed words!
Thanks!
Kevin.

 

[ricicle]

One of the cables is the switch cable whose black should be identified red and go to the brown of the flex (but never assume this is right).

The other cable is the L and N feed from the previous light on the circuit or a JB.As there is only one of these then it could be the last light on the circuit.The red of this cable joins only to the red of the switch cable.The black is the neutral and should go to the blue of the flex (again never assume this)

 

[comms]

It may be the last accessory on a loop in system.
one of the cables will be phase & neutral.
The other cable will be phase (red) & switch return (black).

 

[comms]

Beat me by a second or so ricicle

 

[kevsterdiy]

One of the cables is the switch cable whose black should be identified red and go to the brown of the flex (but never assume this is right).

The other cable is the L and N feed from the previous light on the circuit or a JB.As there is only one of these then it could be the last light on the circuit.The red of this cable joins only to the red of the switch cable.The black is the neutral and should go to the blue of the flex (again never assume this)

Thanks to both of you for replies (very quick at that!!). It sounds like it then, very important not to assume. In the room there are two roses with exactly the same wiring, (one switch per) So would I be right in thinking each one comes from it's own junction box on the circuit?

 

[ricicle]

Beat me by a second or so ricicle

 

[kevsterdiy]

One of the cables is the switch cable whose black should be identified red and go to the brown of the flex (but never assume this is right).

The other cable is the L and N feed from the previous light on the circuit or a JB.As there is only one of these then it could be the last light on the circuit.The red of this cable joins only to the red of the switch cable.The black is the neutral and should go to the blue of the flex (again never assume this)

Thanks to both of you for replies (very quick at that!!). It sounds like it then, very important not to assume. In the room there are two roses with exactly the same wiring, (one switch per) So would I be right in thinking each one comes from it's own junction box on the circuit?

plus does this way of wiring have a name because it is different from both loop in and junction box systems?

 

[MANDATE]

Kev! Unless I've missed something in your posts you have the loop in system and no juction boxes. There's no reason to prevent anyone from having a combination of both because they are basically the same.
Junction boxes meant lifting floor boards to check and resolve problems and ceiling roses just had two terminals.
The ceilng roses now have three sections and about 8 terminals so the junction box has been incorporated.
Each rose has 1 cable to supply power and another to the switch.
There is usually another to supply power to the next rose in the line.
You may even find another if you want two lamps to be operated from the same switch.
If you were just splitting a cable to have two supplys a 3 terminal box is all you would need but if you were installing a junction box for a light you have to cater for the switch cable which means a 4 terminal box is required.

 

[kevsterdiy]

Kev! Unless I've missed something in your posts you have the loop in system and no juction boxes. There's no reason to prevent anyone from having a combination of both because they are basically the same.
Junction boxes meant lifting floor boards to check and resolve problems and ceiling roses just had two terminals.
The ceilng roses now have three sections and about 8 terminals so the junction box has been incorporated.
Each rose has 1 cable to supply power and another to the switch.
There is usually another to supply power to the next rose in the line.
You may even find another if you want two lamps to be operated from the same switch.
If you were just splitting a cable to have two supplys a 3 terminal box is all you would need but if you were installing a junction box for a light you have to cater for the switch cable which means a 4 terminal box is required.

Hi, thanks for the reply.

I think what throws it on first impression is the ancient style of the rose and terminals. As suggested one could be the last on the loop-in system - or both if the wiring has been done in such a way (two in one room)?

I thought that on that age of house it would of just been junction box only system. I forgot to confirm if he has two lighting circuits in the house in general. I have two and my house is 1974. (although last owner wired them together when they changed to a modern CU - don't get me started!)

Ps as I mentioned before he has no earth, he has all original roses and switches (wooden framed back boxes). He asked me about fitting modern decorative metal lighting - from my knowledge you can only fit double insulated fittings.
As for switches - are modern plastic replacements OK?, bearing in mind they would have to use the current screws in to wooden back box and earth terminals would remain unused?

 

[RF Lighting]

You are correct, you must only install double insulated light fittings, but there are some quite nice fittings on the market.

You are fine to install new plastic switches, but you will have to re-use the existing screws.