Kroma wrote:
Hi all,

My parents managed to get their double dimmer switch damp (with wallpaper
paste) and it seems to have broken so I have bought them a new one.

However, upon looking at the connections of the old one (which has worked
fine for about 15+ years) I saw the following connections:
http://tinyurl.com/l84ew

Can this be right? I was expecting reds to L1s and blacks to COMS. I
wasn't expecting just one black, a short red hopping between 2 terminals (an
L1 and a COM) plus a red going to the other L1.

There is only one switch in the room, one of the dimmer controls will
control a ceiling light, the other the wall lights.

Your observations will be gratefully received.

Many thanks,

Kroma

Bizarrely I've come across almost the identical problem recently but
was replacing a horrendous light fitting with a normal ceiling pendant.
Took apart the original fitting and the wiring was done via a block, I
got distracted midjob and lost what was connected to which. I've 3 sets
of wires up there 1 pair of black and red, then 2 sets again of black
and red but the red between the two is not 'split' and just loops away
from the fitting. I've now through a process of elimination (not the
safest way I know) got the remaining 3 blacks and 1 red wire connected
so that the 2nd fitting (i.e. wall lights which I haven't touched) now
works correctly and dims. The light I changed however now only switches
on and off and does not dim which is fine just confusing as to why it
does not dim. No matter which way I alter the wiring I can't get past
this now, if I reverse anything I either get neither light working or
occasionally only one light works.