Adding additional switch+light to existing 2 way circuit

[markfleet]

Hi,

I am a bit of a novice when it comes to wiring so hoping someone may be able to help me.

I have a light in my lounge that is 2 way with another switch in my hall. I am adding a new light to my lounge where the intention was originally to just replace the original light with the new light using the existing wiring/switch which is not too far away. I am hoping now instead to change the existing switch in the lounge to a 2 gang, using the power from the existing circuit to then wire to the additional light (meaning I have the two lights working independent from each other with the existing light being 2 way and the new light 1 way). Is this something that will be possible? I wasn't sure if the fact that the existing light is 2 way complicates things?

I checked the wires in the existing switch and there are 2 reds, 1 black and the earth. There is also some form of junction box further down the wall which I presume is part of the lighting circuit.

Can anyone offer any guidance?

 

[PrenticeBoyofDerry]

Is this something that will be possible?

Yes

I wasn't sure if the fact that the existing light is 2 way complicates things?

No it shouldn't, but you will need Live, earth and neutral for the new light to work, and the method of wiring will differ depending on the existing set up.

I checked the wires in the existing switch and there are 2 reds, 1 black and the earth.

How are they terminated at the switch

There is also some form of junction box further down the wall which I presume is part of the lighting circuit.

A picture would help

Can anyone offer any guidance?

Indeed we can!

 

[markfleet]

Thank you for the very quick response PrenticeBoyofDerry. I will dig out the camera and take the necessary pictures etc in the morning.

Mark

 

[PrenticeBoyofDerry]

I may not be around in the morning to view any pictures or additional info, but I am sure that other members will be only to willing too offer their guidance and I will offer any valid input later in the day if required.
But it sounds like you have your live and neutral conductors looped in within ceiling/floor void. These could be looped in at the ceiling roses or in junction boxes.
If you take a look at wiki it may help you familiarise yourself with the various methods.
//www.diynot.com/wiki/electrics:lighting

 

[markfleet]

Posting the pictures a bit later than I had hoped - had to find camera which was tucked away during decorating.

Firstly below shows the area of the room. You will see the existing switch on the left which lights the single spotlight you can see on the ceiling behind the beams:

Untitled

• markfleet
• 24 Nov 2012
• 1

This picture also shows the extra junction box below the switch:

Untitled

• markfleet
• 24 Nov 2012
• 1

Here is how the switch is currently wired (the loose wire you see in the image was connected to the top right terminal but I had to remove for picture as quite short):

Untitled

• markfleet
• 24 Nov 2012
• 1

Here is a better view of markings on back:

Untitled

• markfleet
• 24 Nov 2012
• 1

Here is how the junction box looks inside:

Untitled

• markfleet
• 24 Nov 2012
• 1

The new lights will be 12v wire lights (Paulmann Salt Wire) which will be on this side of the beams but with the transformer tucked behind the far right beam on my first picture.

Let me know if there is anything else I can provide. Thanks again for the assistance.

 

[Iggifer]

easiest way to do this would be to take L,N+CPC from your existing light to the new position, might require lifting of boards above if there are joists in the way

You will then then need to run a new cable to the switch, how you do this is up to you, if you can, just follow the route of the other cable(s) to the switch

Then connect up at the light as so:

Remember

 

[Spark123]

The JB looks like it has 3 lots of 2.5mm twin and earth in it hence is more likely something to do with the socket circuit.

 

[PrenticeBoyofDerry]

I would agree with spark123, regarding junction box and sockets, tell-tail sign would be if an additional socket outlet was to have the new wiring colours brown of blue, rather than red and black.

By the look of the switch plate you have a live looped in to the switch, which would/could mean that the neutral is looped within the ceiling void as you require both these conductors plus the earth you will need to to a little more investigation. Firstly I would check the existing light fitting and see if there are two black neutral conductors at the fitting.
If there is only one neutral, then the chances are that you have junction boxes in the ceiling void, unless this the last light of that circuit, so further investigation at a second fitting would give us more conclusive evidence.
But you would require to take a neutral to the new fitting from either the light or the junction box if accessible. The live can be linked across from the one at the switch plate to a second gang, then for a two way function you would require a 3 core and earth (strapper) to be terminated between the second gang of switch(for new light) to the location of the second switch to offer the two way function.

 

[markfleet]

Thanks for you responses.

I checked the existing light fitting and only find two grey wires going to the light as below:

Untitled

• markfleet
• 26 Nov 2012
• 1

I haven't yet been able to check the ceiling void for a further neutral / junction box.

Would I be able to take the neutral then from one of these grey wires (other than live)? i.e. without finding further cables in the ceiling.

Also wondering what I would take as the live from the switch? I checked with a meter and either the black OR red would be live depending on the position of the other switch on the 2 way circuit. Just to be clear, the new light will only be 1 way - it is only the original light that will remain 2 way.

 

[markfleet]

So am I right in saying that the new light should be wired like this:

Untitled

• markfleet
• 29 Nov 2012
• 1

from this?:

Untitled

• markfleet
• 29 Nov 2012
• 1

Iggifer's picture looked far more complicated than this. Obviously I am not taking into account the earth.

Not sure on where I pick up the live from in the existing switch being 2 way.

Also what kind of wire would I then require? presumably I technically just need a single core with earth to take live and earth from the switch to the new light and then a single core from the old light to new light for the neutral? I also have a feeling that the new light just needs live and neutral to the transformer without earth so then I could just use a single core all round (although imagine it would be good practice to have earth wired anyway for possible light changes in the future?)

Apologies for all the questions - still alot I am trying to learn in all aspects of DIY since recently got my first house.

Many thanks

 

[PrenticeBoyofDerry]

So am I right in saying that the new light should be wired like this:

Untitled

• markfleet
• 29 Nov 2012
• 1

from this?:

Untitled

• markfleet
• 29 Nov 2012
• 1

That would do the job.

Not sure on where I pick up the live from in the existing switch being 2 way.

It's likely that one of the reds is permanently live at this switch.
The best way to find out which, would be by testing for voltage on a two way function I would expect L1 to be perm live but you need to verify this.
[quote="markfleet";p="2590950"
Also what kind of wire would I then require? presumably I technically just need a single core with earth to take live and earth from the switch to the new light and then a single core from the old light to new light for the neutral? I also have a feeling that the new light just needs live and neutral to the transformer without earth so then I could just use a single core all round (although imagine it would be good practice to have earth wired anyway for possible light changes in the future?)
[/quote]
You need to keep continuity of the earth/CPC, so even though the transformer does not require this, please do not omit the CPC, run it to fitting, sleeve and terminate in a connection block and tuck away safely.
The reason for continuity of the CPC is two fold. One) if fitting is replace with one that requires a CPC. Two) inspection and testing procedures, CPC helps with these procedures.

 

[securespark]

It looks like you don't have a cpc to that spotlight. It's Class I and needs an earth connection.

If you're changing it, does the new fitting require a cpc?

 

[markfleet]

Good point. Yes I am changing the existing light with a new fitting which does require a CPC. As there is earth in the light switch, am I to think this is from the supply and that at worst (if I can't find an earth in the ceiling voide) then I can just run an earth off of the existing earth in the switch to the old fitting?


Going back to getting the live from the existing switch, where should I take this from? Black isnt always live (depending on second the other switch in the circuit)

 

[markfleet]

I have to do this tomorrow so my plan is as followed:

Use 1.5mm twin and earth cable to take live (still not sure which terminal to take this from) and earth from the current light switch initially to a terminal block at the existing light fitting. Here I can provide the existing light fitting with an earth. This terminal block will also take the wires going to the existing light fitting which includes neutral. I will then wire live (from switch), earth (from switch) and neutral (from existing light fitting) to the new light fitting.

Does that sound ok / safe?

Mark

 

[ban-all-sheds]

As there is earth in the light switch, am I to think this is from the supply and that at worst (if I can't find an earth in the ceiling voide) then I can just run an earth off of the existing earth in the switch to the old fitting?

No, you can't just assume that because it looks like an earth wire (or cpc - circuit protective conductor, to give it its proper name) it actually is one.

Before you rely on it as a potential life-saver it should be tested.

See http://www.tlc-direct.co.uk/Book/8.4.1.htm

Going back to getting the live from the existing switch, where should I take this from? Black isnt always live (depending on second the other switch in the circuit)

You have a permanent live there - use a (proper 2-pole) voltage detector to identify it.