What’s going on here?

[NRS]

I unscrewed an old plastic face plate to fit a new modern metal one and got more than I bargained for.

There is no back box. And we have a 2 way switch when this switch could only ever control one light. I can’t work out where the second cable comes from.

Can anyone advise me?

 

[EFLImpudence]

There is no back box.

What do you think the screws screwed into.

And we have a 2 way switch when this switch could only ever control one light. I can’t work out where the second cable comes from.

Maybe there used to be two switches operating the light.

Can anyone advise me?

Make sure you earth your new metal face plate.

 

[NRS]

I think they are screwed into a scrappy bit of wood.

So I guess one cable is redundant and can be terminated?

Absolutely will be earthing the new metal faceplate

 

[ericmark]

I noted my parents old house back box was wood, with Wylex printed on it, so not a DIY thing, and two red and a black wire could switch two lights.

 

[Harry Bloomfield]

and two red and a black wire could switch two lights.

The two wires, black and red, at the same end of the switch, could equally be strappers - which suggests it is a 2-way system, with a second switch located somewhere.

 

[Harry Bloomfield]

I unscrewed an old plastic face plate to fit a new modern metal one and got more than I bargained for.

What probably happened, was....

In the dim and distant past, post 1960 judging by the fact that an earth seemed to be included, the lighting circuit was rewired, reusing the old conduit and timber box set in the wall - to avoid damaging the wall decoration. Timber boxes, and conduits in walls, predate 1950.

Your easiest fix, is to buy a suitable depth of metal box, try to break out the timber box, and set the new box in its stead.

 

[mikeyd]

So I guess one cable is redundant and can be terminated?

No. Unfortunately not.

You need to find the other end of that cable.

 

[JohnW2]

What do you think the screws screwed into.

It looks as if the faceplate screws were screwed into a couple of studs which, in turn, are screwed into something behind. However, the nearest to a 'back box' seems to be some rotting wood with (I think, but I am not certain) no obvious back.

 

[Murdochcat]

I think the installation should be inspected properly

 

[Harry Bloomfield]

However, the nearest to a 'back box' seems to be some rotting wood with (I think, but I am not certain) no obvious back.

I can see a back, but the top of the box has been broken away, probably to access the end of the conduit.