2 gang light switch problem & earthing back box query?

[solorize]

Hi,

I currently have a 2 gang dimmer switch, which the left hand switch operates the main ceiling light, and the right hand switch operates two wall lights.

I decided to unscrew the faceplate to see how the wiring was connected before I bought
a new (non dimming) 2 gang switch.

What I found was...

I have made a note of how everything is connected so when I change the faceplate I know where all the wires go.

But, now I have one problem and a query;

Problem.
The odd thing once I screwed it back onto the wall turned the power on and clicked the dimmer switches was that the ceiling light came on (when I clicked the left switch), but when I clicked the right hand switch only one of the the wall lights came on.. I swapped the bulbs over and still only the same one light came on, so I know the bulb had not blown.

I would have thought that if there was a problem with the right hand dimmer switch that both of the wall lights would not have come on. F.Y.I, I did not yank the wires when I took the faceplate off.

I have since taken the faceplate off again and reconnected the yellow and red wire which is in the Right hand L1 terminal, just in case it was not making a good contact as the wire was visible as seen in the above image. But unfortunately that did not help.

Therefore, can anyone shed any light onto why only one of the wall lights is working ?


Query.
As mentioned earlier I will be replacing the existing 2 gang metal dimmer faceplate with a
2 gang flip (non dimmer) switch, and as such I believe there will be no need to earth the plastic face plate.

Currently as seen in the below image, the earths (even though the two wires coming from the cables look blue, they are a funny kind of dark green if I point a torch light at them), are all connected together in a connector block.

So, when I install the new plastic faceplate, can I keep the earths as is. i.e. keep them connected in the connector block, or should they be fixed to the metal back box?

The only problem I have is that there is no fixing screw in the back box earth terminal, as can be seen @ top right of the back box, in the first image posted.


Regards
Mark

 

[terryplumb]

Earth conductors go to the galvanised box if the switch plate doesn't have an earth terminal.
Most likely cause of one wall light not working is the two conductors in the switch not making good contact, or the neutrals in the floating terminal ( yellow plastic one on the left )have been disturbed when you moved the switch and one is now not connected.
The funny coloured green / blue that are connected to the green/ yellow earth wire , I assume that is sleeving over the bare copper earth conductors from each cable sheath.

 

[solorize]

Hi Terry,

Thanks for your reply, much appreciated.

How do I check the Neutral wires, is there a way to get them out of the floating yellow terminal?
i.e do I unscrew it, or pull it off? I have not used one before so am a bit unsure how to do it and
don't want to damage anything and then not be in a position to put it all back together.

As there is no screw for the backing box earth terminal I am not sure how I can attach the earth
wires to the backing box. I have an old plug which has screws that attached the wires
to the pins, would one of those fit? or are they too thin or not have the correct thread.

If I can't get a screw would I be better off buying a replacement metal faceplate, which will have
and earth on it, so I can just wire it back up as per the current existing one.

 

[terryplumb]

Buy a galvy box and use the screw from it. Or if you can't find a screw that fits ,drill it ,tap it for a screw that will fit . Removing the galvy box will likely result in some damage to plaster etc. Can't make out exactly what the yellow connector is ,but any insulated terminal connector will do to replace it if need be.( Looks like the type that twists onto the wires)

 

[solorize]

I was pondering if I could use the screw from the current metal face plate and
move the wire up and attach the crimped loop to the earth terminal (on backing box)
and fix it in place with that screw.

The twist connector, should I just try and twist it around a bit more, or should
I un-twist it and check the wires and then twist it back on, if so how tight do
you twist it to get a good connection?

 

[terryplumb]

Unless you have a new insulated connector / terminal block to hand ,I wouldn't try to undo the neutrals from that yellow connector. You could try twisting it to tighten up. Don't like them ,or use them myself.
Do you have a multimeter ?
The earth's ( in greeny blue sheath) should go to the earth terminal ,if they don't reach you could use the flying link .

 

[endecotp]

How do I check the Neutral wires, is there a way to get them out of the floating yellow terminal?

That thing is called a “wire nut” and the Americans use them.
You don’t generally see them in the UK, though Wikipedia tells me they are not actually banned.
If I were you, as you suspect it might not be making contact, I’d probably replace it with a screw terminal or Wago.

 

[solorize]

Terry,

I do have a multimeter, but its been a fair few years since I used it last.
I will give the "wire nut" (thanks endecotp) a twist tomorrow and see if the
second light comes back on.

I have a couple of 2 port Wago connectors, do you know if you can insert two wires in to a single port?
So that I can put two wires each into the two ports, so that all four wires are connected, as is with the 'wire nut'

 

[terryplumb]

No ,one conductor in one port. Don't put two in one port.
Pick up some connectors with your new switch.

 

[solorize]

Thanks for the info.

With regards to the connectors, can I just use the standard ones like below, if so
I see there are various Amp versions; ( 30, 20, 15, 10, 5 ,3 Amp), along with the Ampage, does this just denote the size of hole for the wire to go into?
Therefore, do you know which one I would need?

I take it that I just put two of the wires in one side and the other two in the opposite side?
If so, does it matter which ones I put together?

Sorry for all the questions!

 

[terryplumb]

The amperage relates to the current
rating of the connector . The 10 amp would be more than ample,current wise, and will give you more space for 4 conductors ,which can all go together in one terminal block,all entering from one end if it's easier.
As long as all 4 are in contact with each other ,that's the aim.

 

[solorize]

OK, thanks Terry.

I've orders some now, so once I have them I will re-wire the neutrals into
it and then see if that gets the second wall light working again.

I've also ordered a new metal faced switch so once that arrives I will wire
that up, as per the current switch, so I can have the earth from the new face
plate go to the earths in the connector so don't have to mess about trying
to earth the back box, (just hope the new metal one has an earth connection on it).
Plus the other half prefers a metal over the plastic one.

 

[solorize]

Hi again,

One thing that has been confusing me with the wiring, is that I am
unsure what the yellow wire coming from the ceiling cable is doing
and why it is going into the L1 on the wall light switch.

I have tried to replicate the wiring, as a diagram below, so you can
see exactly how it is all wired up.

If you know can you explain to me why it is wired up like this?

 

[terryplumb]

Are you sure the diagram is a true replication of what you have ? Your photo of actual wiring is difficult to ascertain which terminal the red conductor from the 3 core + earth cable is actually connected to ( 3 core is the sheath that contains red ,blue and yellow conductors).

 

[endecotp]

Look inside the ceiling light fitting and see what happens to the yellow wire there.

Is there a second switch for any of these lights?