Lighting Wiring Help!

[slr010877]

I have recently purchased a house. In the hallway we have two, two-gang light switches, one which has a switch for the upstairs landing light, and one for the downstairs hallway light. The other two-gang has another switch for the downstairs hallway light and the other switch is supposed to be for a light under the stairs. Everything works EXCEPT for the light under the stairs. After doing to obvious (check the bulb etc) I decided turn off the power and look at the back of the switch. Which looks like the attached image.

In short, the hallway switch that works is wired with a red cable in COM, a yellow cable with red sleeve in L1 and a blue cable with red sleeve in L2.

The non working switch to the under stairs light is just a twin and earth cable run into the back of the switch (the other end of the twin and earth cable goes directly to the light rose), with a brown wire to COM and a blue wire to L1 (both cable runs are earthed to the Earth point at the back of the switch box).

I am assuming the wiring for the under stairs run is totally incorrect, but I do not know how to go about correctly wiring the connection to the lighting under the stairs. I realise this is not really a full picture or how everything is put together, but I was hoping somebody may see the obvious solution! Happy to get pics of connections if they are needed.

Any help greatly appreciated by a novice!

Many thanks!

Steve

 

[ban-all-sheds]

You basically have to choose between Plan A and Plan B.
PLAN A:

• Learn how lighting circuits are wired.
  • //www.diynot.com/wiki/Electrics:Lighting
  • http://wiki.diyfaq.org.uk/index.php/House_Wiring_for_Beginners#Lighting
  • http://www.google.co.uk/search?q=uk+lighting+wiring+(basics+OR+101)
  • //www.diynot.com/wiki/Electrics:books
  • //www.diynot.com/wiki/Electrics:index
• Get a multimeter and learn how to use it.
• Identify which conductors are which at the switches and the light positions.
• Work out what should go where and connect everything up properly.

PLAN B:

• Get an electrician.

There are some irresponsible people here who will tell you that there is a Plan C, which is to start trying different things without really knowing what's going on, hoping to get it working by luck, or by blindly following instructions to put-this-wire-in-that-hole without any idea as to why. Please don't listen to them - you must know what, and truly understand what, you are doing.

Electrical-installation-by-guesswork is a foolish idea.

There is no Plan C for anybody sensible

 

[EFLImpudence]

The non working switch to the under stairs light is just a twin and earth cable run into the back of the switch (the other end of the twin and earth cable goes directly to the light rose), with a brown wire to COM and a blue wire to L1 (both cable runs are earthed to the Earth point at the back of the switch box).

If that is all there is - one cable from switch to light - then obviously it cannot work.
I assume it was installed by someone with no idea what they were doing do.

You would need to run another cable from the supply somewhere (is the consumer unit also under the stairs by any chance?) to the light and wire it correctly.

 

[slr010877]

Think I knew that this was the only way to go, but I had to make sure something was not obvious!

Thanks for the honesty!

 

[securespark]

How is the cable in the under-stairs light fitting connected?

 

[sparkwright]

S

How is the cable in the under-stairs light fitting connected?

Some common sense at last.

 

[securespark]

Steve? Can we have a picture ?