What size blanking plate for this small back box

[Caecilius]

I've got two unused back boxes that I want to cover with blanking plates. They appear to be for communications rather than power and look slightly smaller than the standard back boxes that are used for switches and sockets.

Picture showing back box with ruler. The back box is square and about

70mm across:

Any thoughts on where to get a blanking plate for these sorts of boxes? I think a standard socket/switch single blanking plate will be too big. Are there different sized comms back boxes?

[Andy Burns]

Box as a hole is smaller, but Isn't the critical dimension between the centres of the mounting lugs? 2 3/8" in old money = 60.3mm, looks rightish allowing for whatever parallax error exists in your photo ...

[Caecilius]

Yes, good point. Maybe the standard blanking plates will work after all. I'll give it a go. Thanks.

[williamwright]

Nice nails

Bill

[Dave Plowman (News]

A surface mounting socket blank plate is smaller than one to replace a flush one. But has the same fixing centres. Surface mount boxes have rounded 'corners'.

[ARW]

Looks good to me - apart from what looks like a snapped off screw in the left hand lug

[ARW]

I assume you are talking about the MK metalclad stuff?

[Roger Mills]

Looks like a standard size single box to me.

It also looks quite old. The standard screw thread pitch changed a few decades ago, and you may need the old type rather than current screws.

[Brian Gaff (Sofa]

If all you are doing is hiding them, I guess a couple of fishplates made of a couple of bits of tine could be all you need, slightly cranked at one end to allow the screw head to be screwed down and a self tapping screw at the other outer side for the normal blanking plate. Brian

[charles]

my tool box has an M3.5 tap to 'modernise' old boxes.

[Tricky Dicky]

All the black painted back boxes I have come across are old imperial types. Modern sockets and plates do cover and match up but you will find the tappings are 1/8? but running a 3.5mm rethreading tool through them will allow current screws to tighten.

Richard

[Dave Plowman (News]

Pretty well any make metal clad surface mount.

I've no experience of surface mount plastic. ;-)

[charles]

They used to be 4BA !

[Andrew]

My tool box has an M3.5 tap to rescue cross-threaded back box threads :-).

This seems to occur more often on a plastic box for flush fitting in a plasterboard wall.

[williamwright]

Definitely 4BA

Bill

[Dave Plowman (News]

I'd have hoped since we've left the EU we could go back to good ol' British Association screws. Instead of that metric rubbish. And, of course, re-design BA totally so it wasn't metric based.