2 way light switch problem

4 May 2015
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United Kingdom
Hi all - new here :)
I have a question about adding a 2 way switch to some existing wiring that goes from my landing to my loft.

This is where I started:

On the landing - 1 gang, 2 way switch that controls the landing light. The other switch for this is at the bottom of the stairs.
Wiring for the landing switch: Common - Red with red sleeve. L1 - Black + Yellow with Red sleeve. L2 - Red + Blue with Red sleeve.

In the loft - - 1 gang, 1 way switch. I believe power is supplied from the landing light ceiling rose. (I think my Dad done this years ago) Common - Red. 1-way - Black.

So far this all works fine.

Next I have bought some 3 core cable (black, brown, grey + earth)

I have changed the switch on the landing to a 2 gang switch.
The wires for the landing light (switch 1) are all back in their original places. I have double checked this as I done a diagram before removing them.

Next I am taking the 3 core cable from switch 2 to the loft. Switch 2 on the landing is wired as follows:
Common - Brown. L1 - Black (tagged with brown). L2 - Grey

I have also changed the switch in the loft to a 2 gang switch.
One of these will obviously be the secondary switch from the landing switch.
The second switch will eventually control additional lighting in the loft.

So, the new 2 gang switch in the loft -
Loft Switch 1
As on the landing:
Common - Brown. L1 - Black (tagged with brown). L2 - Grey
Now the existing cable that was already there for the switch (as I want to control this light from up in the loft too) as mentioned earlier is a red cable and a black cable - power supplied from the landing light ceiling rose.
I have wired this as follows:
Common - Red. L2 - Black

PROBLEM: Loft light is permanently on, unaffected by any switching
Landing light still works as it should.

What have I done wrong??

Thanks in advance ;)
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In the loft move the red wire from common to L1. Everything else sounds correct.
he has made the loft light switch on the landing a 2-way
the second way in his new switch is spare (for now)

no switching of landing/hallway light from new switch
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Yep, as Iggifer has said. The added switches and wiring are purely for 2 way control of loft light.

Anyway.... It almost works as it should, but I seem to have a new problem. While both switches will turn the light on, if either switch is on, the other wont turn it off..... :(
So what am I missing? Do I need supply to both switches?? I was hoping not. As I understand, the supply would come from the existing wiring in the loft down the link cable to the switch on the landing.
Am I missing something in the loft switch that makes it 2 way??
You have linked a perm live between the two gangs then.
If I understand correctly what you have done, is that you have created a two way function for the loft light (not sure why) but the loft light originates from a ceiling light, then to the original switch in loft?
From there you have routed a strapper between the switch in loft to a new 2 gang switch on landing?

Just out of interest in the regards to conformity, how did you route this cable?
Is it in the permitted safe zones and RCD protected?
Ah, I see what I've done now :p
It's routed down a wall cavity from the loft to the landing switch alongside another cable.
It would be RCD protected via the main fuse box which has separate fuses for upstairs lighting and downstairs lighting.
I still don't understand why a two way function is required for the loft.
I don't think there is an intermediate needed EFLI?
As far as I can workout, the second gang(loft) is also for a second loft light!
Have I got completely confused?
I was thinking it was a loft conversion; not just 'a loft'.

I'll get me coat. :)
Depends what you call a loft conversion...
Anyway here's a basic image of what I am doing:

So the ones labelled 0 are lights downstairs unaffected by this job. Switches 1 (already in place) and 2 are both 2 way switches that control the landing light.
Switches 3 and 4 are meant to operate the loft light in the same way that switches 1 and 2 operate the landing light.
Switch 5 will be a one way switch for additional loft lighting.

My mistake.

I was thinking you wanted to turn off the landing light when you were in the loft. :)

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