lighting switch confusion...please help!

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hello chaps,

i have a new found respect for you trade, me being a plasterer and all.

re-plastered my hallway and landing recently and replaced the 2 gang 2 way switch in the hallway for some new and clean.

Wired it like for like but now the lights are just not behaving and doing whatever they feel like, or so it seems.

I have a 2 gang switch downstairs which controls both hallway and landing and a single switch upstairs for the landing only.

I have attached a crude diagram of what i have downstairs, the cable i marked and wired the same way in the new switch but now the lights work randomly.

any help GREATLY appreciated.
 
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Assuming that the switch on the right is for the downstairs light - that appears to be correct and should work.
The switch on the left should operate the upstairs light via a two way on the landing.
For simplicity sake your conductors colours at this switch should match the upstairs switch.
So Red = Common
L1 = Yellow
L2 = Blue.
At both upstairs and downstairs switches.
 
Don't suppose it really is random.

Trowelmonkey - do you still have the original switch?

I'm wondering if you muddled up which COM goes with which L1 & L2.

See //www.diynot.com/wiki/electrics:twogang. If you have the old switch, see if there's a diagonal line across the back.

And while you're here, any chance you can settle the old argument about whether plasterers damage cables if they are clipped to the wall and not under capping, or if that's not so because you're too protective of your edges?
 
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thanks for the replies guys.

unfortunately the wife threw the old switch out before i put the new one on!

I marked the cables so that i knew exactly which went to which but seems i may have muddled some how, if tell you that depending on which way i have these switches, i.e. on or off, the upstairs switch can affect either light so guess i must have not realised that there may have been a line on the back of the old switch!

Any ideas then in this case?

On the plastering question ban-all-sheds, i've never damaged a cable yet, i assume the damage you mean happen when the spread is floating? and by edges you mean feather edges or trowel edges?
 
I tended wire two ways with yellow to com, red to L1 and blue to L2 (or did prior to colour change)
Can we assume the one way light (hall) is functioning correctly and the cables are twin and earth/three core and earth?
It could be worth looking at the configuration of the single gang landing switch, this could help this figure out.
Although some switches look the same, they are not also so, you may have had something like this, that you copied without actually looking at the terminal points.
 
by random which obviously can't really be the case
:D

using the 2 gang switch downstairs, if i switch both switches to on, nothing happens, darkness, then i switch the left (landing switch) both lights come on, i can then switch the right switch which turns the downstairs light off but then the upstairs switch does nothing at this stage, it can however switch both lights off if i have the switches downstairs set differently.

CONFUSED.COM
 
If the operation of the both lights are being effected, then firstly check if the cables are t&e and 3c&e and sheathed. This will hopefully divide the cables in to the correct sets.
You may have the red cores in the wrong gang!
 
As you're in the trade, isn't there a friendly sparks on site you could get to come and put it right for you?

PJ
 
Photograph the rear of the upstairs and downstairs switch showing the positions of each cable with respect to their terminals and post them here.
At the downstairs switch you should be able to physically determine which cable is Twin and Earth and which is Three core and earth.
Look back through the questions asked and provide answers - otherwise we will be taking one step forward and two steps backward.
 
HA!

Coms were the wrong way around! Obviously the old switch was a slightly odd setup on the back and if i'd have had the old switch i'd have been able to see.

Moral to that story, keep the old switch safe until the new one works.

Thanks a lot chaps! :D
 
And as a matter of general principle, train your wife to never make a decision to throw anything of yours out.
 

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