Old Style Light switch box

Hi,

Just redecorated the bedroom which also included a new light switch plate. When I came to put on the new switch plate, it became obvious that it wouldn't fit the existing box as the width between the switch plate fitting screws are too wide.

The existing box is a solid metal (looks like steel) and is embedded into a solid plastered wall. I am guess it may be an original fitting from when the house was built (1930's).

I don't particularly want to extract the box. Is there any other option that allow modern standard switch plates to fit older boxes? Or does anywhere stock modern style (white plastic) switch plates that have narrower width between the mounting screws?

Thanks in advance,

Mike

All of the modern switches that i have fitted have the same width as the old-style standard boxes.

The screw thread sometimes needs tapping out to 3.5mm but otherwise they fit.

You must have a box for a special switch. What is the distance in mm between the two holes?

Take a picture so we can have a laugh (sorry I mean look)

Sounds like an old dolly switch back box

Here's one from my house:



You can see the silver adaptor which allows newer style switches to be attatched to the old style boxes.

Not sure where you would get them from these days though.

Maybe a local metal worker could knock one up for you?

MK do 'em....

3840 ZIC.

Is that the switch you rewired in conduit?

Buy em here http://www.sparksdirect.co.uk/mk-box-fixing-flange-old-to-1g

securespark said:

Is that the switch you rewired in conduit?

Click to expand...

That's the first one I did....

mjm22 said:

The existing box is a solid metal (looks like steel) and is embedded into a solid plastered wall. I am guess it may be an original fitting from when the house was built (1930's).

Click to expand...

It is most likely cast iron which makes extraction easy than you think once you know how. The trick is to use a Dremel tile cutting bit in a drill or one of those multitool things to cut a neat square out of the plaster back to the brick exposing the cast iron fitting which is screwed onto the steel conduit.

To remove the cast iron box thing you now take a cold chisel and wearing eye protection wack the cast iron box. The best place is around where it is attached to the conduit. The cast iron box will crack/shatter allowing it to be removed (watch it will be razor sharp) leaving the steel conduit undamaged.

You can now fit a standard metal back box. Most likely it will need to be a 25mm deep one and you will probably need to use a step drill to make a hole in the right place to fit over the left over metal conduit.

Done several of these in my house, as when it had been rewired all they did was screw surface mounting boxes over the top. The first one I took out I pulled out the cable and used an angle grinder to cut it. Not a good idea as it creates an awful mess.

Here is a picture of the last one I removed, you don't even need to withdraw the cable from the conduit.