Wiring question

[KSC]

Could I seek some advice on what I hope is a simple problem?

One of the downlights in my hall went, and when I found out that it wasn’t the bulb, I went to change the transformer.

When I pulled it out, I found that its two wires are connected to a junction box. Inside, its blue wire is connected to a piece of red wire, but I found that this was unconnected at its other end. The brown wire from the transformer in the junction box had no wire joined to it.

Inside the roof cavity, I found, to my surprise, that there is a rose, without its top, which has been used to join cable on the circuit. There are five wires in the first group - four blacks and a blue. There are four wires, all reds, in the second, middle, group. There are three wires in the third group: a red, a cable with a brown (and a cut blue) and red wire which I found to be unconnected at the other end.

I know the cable with the brown and the cut blue in this third group is the switched live to a 3-way wall switch.

I presume that the first block of blacks and a blue in the rose is the neutral terminal group; and that the second block of reds is the live block.

All the other lights on the circuit are working.

Am I right in thinking that the loose (red!) wire from the blue in the junction box should go to the first, neutral, group in the rose; and that the loose red from the rose joins to the brown from the transformer in the junction box?

I don’t want to do anything by trial and error and if it’s more complicated than this I will call an electrician – but I don’t want to seem foolish if it’s very simple.

Many thanks.

 

[ban-all-sheds]

I don’t want to do anything by trial and error

An excellent position to take.

Another excellent thing to take would be photos.

And a diagram showing what's connected to what and where, and continuity checks with a multimeter would probably be useful.

 

[KSC]

Thanks. Have uploaded two photographs. I can't pull the rose out any further I'm afraid. The black wires in the first group haven't come out very well (they include the blue wire which you can see). The loose brown from the rose is on the right hand side.

Untitled

• KSC
• 30 Mar 2013
• 1

Untitled

• KSC
• 30 Mar 2013
• 1

 

[Johnmelad]

Larger pictures please.

 

[Zebra579]

Sounds a right mess.
Sounds like the transformer isn't connected to anything which is why it doesn't work. but you say it used to, which is odd.
If you know what you are aiming for ie three terminals in your main junction box or ceiling rose, which are permanent live, switched live and neutral (and earth of course) then get rid of everything else, all those ones which go nowhere, and create that. You are right in thinking that the bunch of reds together in the rose is the permanent live, and the blacks and the blue are the neutral. After that it all gets a bit complicated though. The third terminal ought to be switched live but I'm not sure what all this business is with the brown with the cut blue which goes to a (do you mean 3-gang, not 3-way?) switch.
What you want going to your transformer, via your other juction box, is switched live and neutral, not single core unsheathed cables, but a piece of twin and earth.
Obviously the rose without its top is not good, as it has unenclosed live connections. You should do something to enclose them, ie redo the whole thing in a junction box, or at least find a top for the rose.

 

[KSC]

Here’s a better picture though there are so many wires that it’s hard to make them all out.

I guess the wires may have come loose when I pulled out the transformer, though obviously it had stopped working before that.

Yes, the brown with the cut blue goes to L2 on a 3-way switch.

I have drawn a diagram as ban-all-sheds suggested. There are four blacks and a blue in what I think is the neutral block; four reds in the live block; a brown and a red in the switched live block, and the loose red wire (on the right of the picture).

I’ve also drawn a diagram of what I think is going on. I think there’s a loop in and loop out, a spur, an extra light (the wall lights come on at the same time as the
downlights) a permanent live to the three-way switch (where the neutral is looped – the blue from the rose, I think), and a switched live to the same switch (the cable with the single brown wire).

I’m pretty sure that the loose wire from the junction box goes to the switched live, and the other to the neutral on the (cluttered) rose.

But as I say I don’t want to do trial and error.

Thanks again.

//www.diynot.com/network/user_album_update.php?album_id=15885

 

[Zebra579]

That link doesn't work. When you say 3-way switch, what do you mean?

 

[KSC]

Oops, sorry, try this.

I mean it's one of three switches that control the hall lights - i.e. it's a 2 way switch - by the front door - linked to an intermediate switch at the end of the hall and then another 2-way switch on the landing.

It is (also) a 2-gang switch as it also controls the outside PIR light and thus it has the the looped neutral.

Hope these links work. As you can see, I can't put a top on the rose as the wires come through and round it. My guess is that there was a rose there originally and the previous owners adapted it for the downlights and wall lights.

Untitled

• KSC
• 30 Mar 2013
• 1

Untitled

• KSC
• 30 Mar 2013
• 1

Untitled

• KSC
• 30 Mar 2013
• 1

 

[Zebra579]

Oh., you mean two-way-and-intermediate.
OK, it's a bit weird having the feed to the switch and the switched live in separate cables, but if that's the way it is, then what I think you need to do is remove that loose red single core, get a new piece of flex or twin-and-earth, wire it into the switched live terminal of your rose and the neutral terminal, and connect the other end into your junction box for your transformer.

 

[KSC]

Thanks, Zebra. Thought it was as simple as that but always prefer to check. Will use twin and earth as you suggest to get the light back on and then get round to sorting out the bigger mess.