Unexpected coloured wires and two going into L1 on dimmer switch

[JohnW2]

On the contrary John ,the metal clips of the decorative, clip on front, connect directly to the metal switch plate,not any plastic . Take a look at the op's picture of the front of the switch plate.

I confess that I hadn't noticed that photo of the front, hence my previous comment ..

What we can see certainly looks like plastic, but that earth terminal makes me wonder what's on the other side. ...

The 2 square holes are where the springs connect the decorative front to the switch plate.

I'm pretty confused now, in trying to reconcile the pictures of the front and back. You are probably right. For what it's worth, my comment quoted above does indicate that I presumed the presence of the earth terminal probably indicated that there was something which needed to be earthed!

Kind Regards, John

 

[plugwash]

Okay, here’s what the backbox looks like…

That is a rats nest, it seems there are a large number of cables and some of the joints have been made outside the box. Possiblly because the installer ran out of space in the box. The number of cables seems far greater than can be reasonablly justified by a single lightswitch.

Ideally it needs a thourough tidy up followed by thourough testing. Potentially the box also needs replacing with a larger one to accomodate all the connections.

But I really can't reccomend someone who is new to electrics tries to tidy that up themselves, they may well end up making things worse.

Easily fixed by connecting the earth wires which surely must exist in the backbox to the switch.

IMO one you have found one instance of dangerous bodgery, you have to assume that there are other instances. I would be wanting to at minimum test the earth before assuming it was a good earth.