Halogen spot light wiring question

[Paulll61]

Hi All

I stumbled on this site after a Google search - like you do ... anyhow, I have not been able to find a specific answer to my question - but maybe I have not been able to match some descriptions to what I am looking at, see below.

Basically I want to wire a halogen spot light rail to an existing ceiling rose, with an existing on/off switch on the wall (ie no dimmer).


This is what I have:

Ceiling wiring (two red, two black, one much thicker/stiffer wire sheathed in a black)

Transformer (brown and blue wires shown)

Lighting mount (three white and three black wires - there are three spot lights on the rail)

The lighting circuit is on a 5 amp fuse.

So ... which do I connect to what?

I'm no electrician so clear instructions will be very much appreciated

Cheers

Paul

 

[TicklyT]

You need to know exactly how the wires connected to the old ceiling rose.

You made some notes before you took it down, didn't you?

My first guess - and it is only a guess - and assumes you just have one switch controlling one light - is the two reds from the ceiling connect together in a piece of choc bloc, and to nothing else.

One black wire connects to each mains voltage terminal of the transformer - the black carrying the switched live to the live side, and the other to the neutral. We don't know which of the two is the switched live - you will need your notes for that. It is usual for the switched live to be marked with a red sleeve, but it is often omitted.

The CPCs or earth wires should be sleeved with green/yellow sleeving, not black, and terminated on the earth terminal of the fitting.

The three white wires from the fitting connect to one 12 Volt terminal of the transformer, and the three blacks to the other.

If there is more than one switch, or the switch controls more than one light, the wiring of your lighting circuit may be totally different.


Modern light fittings often have little room for multiple cables, so you may need to fit a junction box above the ceiling to terminate the cables, and run a single cable from that to your fitting. Concealed junction boxes must remain accessible for inspection and testing.

//www.diynot.com/wiki/electrics:lighting:single_way_lighting may help you understand how lighting circuits are wired.

 

[Lectrician]

The two sleeved cores are your earth - probably not sleeved black, but dark green? That would be the old earthing colour. Replaced now by green/yellow. This would be connected to the earth terminal on the light fitting.

Assuming you only have this single light on the circuit, then you have two cables, one is the feed and one is the switch. The two reds would be joined together in a terminal block on their own. One of the blacks would then be the neutral for the light fitting, and the other black would be the switched live for the light fitting, which should be sleeved red, although this is often ommited by lazy old school sparks. The only way to determine which is the neutral and live is by tracing the cables (if you have a loft above), or by using a test meter of some sort. Theoretically it would not matter which way around you got them, but you should do it the correct way.