Light switch wiring - help appreciated

I've found a displaced wire in a double dimmer switch:
http://i246.photobucket.com/albums/gg102/BertCoules/Switch.jpg
All three screws on the right-hand unit seem to be tight so it's not clear where the wire has come adrift from. A quick Google search hasn't turned up an obvious answer so any advice would be welcome. Many thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sorry, a line got lost...
The obvious location is the empty L2 but obviously I want to be sure.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bert Coules wrote:

There look to be two empty L2s. I presume one of the circuits is not working? and if so use the l2 of that particular gang. It is rather strange that you say there are no loose screws (apart maybe from whoever fitted it?)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bob, thanks for that. No, both circuits are working, each one controlling lights at either end of a long room.
The position of the loose wire suggests very strongly that it come from the right-hand unit, so am I correct in thinking that the RH L2 is the one to use?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

With any switch or dimmer, you need a feed and a return. With a double switch, that feed may be shared between them. So a minimum of three wires into the wall in this case.
Your pic shows two dimmers wired in series. There is no way they can be controlling two circuits as is.
My guess is the loose wire should go to either of the terminals with that link wire. And should be obvious by a loose screw. A wire can't pull out of a properly tightened one.
--
*If love is blind, why is lingerie so popular? *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dave,

And your guess is quite correct. I foolishly didn't check the two common terminals for loose screws, but now I have: LH Common was indeed loose and putting the wire into it has restored correct operations.
Many thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 14 Jun 2017 13:09:44 +0100, Bert Coules wrote:

Are either of those lights controlled by another switch? Do all switches of either light toggle the on/off state of *only* the redpective light when operated?

I'm a litte confused why the units have the word "transformer" on them and a "Pri" voltage rating but no obvious seconadry voltage. I'll ignore that for the time being. B-)
Looks to be three T&E's in that box. The upper two connected to the L1's. The wavy line with arrow I'd interpret as the dimmed (and switched?) output but the are strapped together like commons. The lower cable with the adrift wire, is that wire permenantly live? Or does it switch with any involved switch?
Something odd going on, probably some back feeding but I can't work out where if there is no two way switching involved.
--
Cheers
Dave.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dave,

I can't answer your questions, I'm afraid, nor can I shed any light on this:

But I can offer the fact that one of the two units has never satisfactorily dimmed its lights (ceiling mounted LEDs) to a completely off position (and still doesn't). What that means I don't know (simply a matter of the unit being faulty, perhaps?).
Incidentally, I removed the faceplate to investigate whether or not the switch could be moved just a couple of inches to avoid disappearing behind a possible new bookcase; I was hoping there might be enough play in the cabling inside the stud wall. There isn't, but the move could happen if I extended just one of the wires. Is there a recognisedly safe way of doing that?
Many thanks again.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 14/06/2017 15:01, Bert Coules wrote:

Might just be a reflection of the fact that some dimmable LEDs have a poor dimmable range. (dimming can also be upset if there is a mix of lamp brands / types being dimmed on the same switch)

If you are leaving the existing box in place (and say putting a blanking plate over it) and installing a new switch to its side, then any kind of terminal is ok - chock block, Wago terminals (like that joining the blue wires in your switch), or crimped extensions are acceptable.
If however you were planning on heat shrinking the wire extensions and then plastering them in, then something "maintenance free" would be required like the wago or crimps.
e.g.:
http://wiki.diyfaq.org.uk/index.php/Cable_crimping
--
Cheers,

John.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John,
Thanks for that. It will be a blanking plate over the original back box, so I'm reassured that I can use chock block. Those Wago terminals do look very neat though.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 14/06/2017 17:14, Bert Coules wrote:

TLC will sell them individually if you want (rather than buying a whole box)
--
Cheers,

John.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John,

That's useful to know, thanks. It's really quite galling to have to buy in (relative) bulk when you only need one or two items.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Not sure any LED can be smoothly dimmed to extinction then up again. Seems to remember that problem in the early days of LEDs in a TV studio. They seem to need a sort of 'strike' voltage. So could be the dimmer makers set the minimum to above this?
--
*If work is so terrific, how come they have to pay you to do it?

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 14/06/2017 17:43, Dave Plowman (News) wrote:

The ones I just fitted in my lounge will dim right down and go back again. But they won't start from cold on the lowest setting. You need the setting up a bit brighter to get them lit.
These:
https://www.ledhut.co.uk/led-bulbs/e14-led-bulbs/4w-e14-candle-shape-bulb-warm-white.html
--
Cheers,

John.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks, John. That sort of explains what I saw.
--
*Whatever kind of look you were going for, you missed.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 14/06/2017 18:16, Dave Plowman (News) wrote:

Supposedly with the Varilight IQ range of dimmers they have a "boost" capability to start lamps even at low settings. Also switch from leading to trailing edge automatically depending n the type of load.
--
Cheers,

John.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 14/06/2017 21:04, John Rumm wrote:

That's a new one on me. I am familiar with the VPro and you have to programme the dimmer to the lights.
--
Adam

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ARW wrote:

Adam, something I can't do with my present lights (even the ones which will smoothly dim right down to nothing before the off position) is run them at a very low setting: they tend to flash intermittently. Would different switches enable me to do that, do you think? Might it be necessary also to replace the lights themselves?
Many thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
John Rumm wrote:
> The ones I just fitted in my lounge will dim right down and go back

As do mine in all other areas of the house, including the ones controlled by the left-hand unit in this double switch, which is what leads me to suspect that the right-hand unit has a fault.
What I can't do with any of my LEDs is keep them at a very low setting: they flash on and off intermittently. Would changing the switches help with that?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 15/06/2017 10:40, Bert Coules wrote:

It might, but its as much a function of the lamp as well as the switch.
--
Cheers,

John.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.