Hwlp with double switch landing/Hallway wiring

[davegriff]

Hi,

I have a light in the upstairs landing that is also wired from the hallway.
Currently, the hallway light has two switched - one for the downstairs light, which works perfectly, and one that is supposed to switch n the upstairs light when it's off and vice versa.
It doesn't do that.
The wiring at the mment is as follows
One red into the C point and one black into the L1 point - this is for the downstairs lights that work.
One red into the other C point, and one Blue in the L@ point and one yellow in the L1 point.
There is also the Green earth wired to the earth point.
the lights upstairs do funny things...they don't come on when the downstairs one is switched and they do if the upstairs switch is switched etc etc
What am I doing wrong ?
Or is it the wiring upstairs ?

 

[andy]

how is the other switch wired. from what uve said the 3 core cable shud have red in C, yellow and blue in L1 and L2. the red and black from the light shud go into L1 and L2

 

[ban-all-sheds]

Go to the For Reference section, and look at the top pair of switches in the "Wiring two- and three- way switches" diagram. The bottom one of those two is what you have in your hall, the top on is what you should have at the landing switch. It doesn't matter whether Yellow is in the L1s or L2s - the 3-core cable should be installed so that it connects C-C, L1-L1, L2-L2.