In my kitchen the walls are of painted plywood screwed to 2"x3" verticals. I find that the electrical sockets have metal back boxes of the type normally used in plastered walls. They are firmly screwed in place to the plywood along their front edges.
Is this dangerous or merely unconventional? In particular, are the plastic dry-lining back boxes you get these days designed to contain a fire originating at the socket?
thanks for any suggestions,
Robert
I don't think it is dangerous, or particularly unusual. All the sockets in our house were installed like that (metal boxes screwed to battens behind the plasterboard).
I doubt a plastic dry-lining box would offer as much fire protection as a metal box anyway? Apart from anything else they have great big knockout holes on the sites where the clamping mechanism is.
Steve
On Mon, 21 Jan 2008 02:11:09 -0800 (PST) someone who may be RobertL wrote this:-
How precisely are the screws arranged? Are they between the box and the plywood, thus simply jamming the box in place?
The normal way of securing metal boxes in this sort of wall is to put a bit of wood between the uprights and screw the back of the box to this. The bit of wood is generally inserted before the wall is put up, otherwise it is difficult to fit in place.
It is more inconvenient than dangerous. If the screws are as I surmised then the screws will no doubt eventually work lose and the socket will fall out. This is slightly dangerous, but rather more inconvenient.
All boxes are designed to contain fires. That is one of their functions. If it is a new installation I would have the boxes replaced by whoever put it in, if it is an old installation I would replace them myself. In both cases I would have hollow wall boxes put in.
They're used in skirting boards etc too. They are the normal type of backing box used for flush mounting - anything else is a 'special'.
I'm not quite sure what you had expected to see.
Yes- but they are specifically for plasterboard. Although no real reason you can't use them elsewhere - apart from the fact they're ugly.
I'd be more concerned about the plywood walls in a kitchen presenting a fire hazard. Have you taken advice about this?
I dislike dry lining boxes in that you see the lip which spoils the look of an expensive socket. So always use metal ones in plasterboard. I simply fix batons (longer than the sides) either side of the opening behind the plasterboard using brass screws and make good the heads. Some extra holes may be needed in the box sides towards the front to get the best place for the fixing screws to the batons. You could do the same to plywood, but glue and clamp the batons till the glue sets since you may not want screw heads showing or whatever.
I realise this is far too long winded for a pro in a rush, but eminently suitable for a good DIY job or indeed anyone where appearance matters and it's impossible to insert a noggin.
That's an intersting thought. The whole kitchen internal wall is wood: plywood inside and mahogony tongue and groove outside. Hous ewas built in the 1960s.
Thank you all for your replies about the boxes. FYI the plywood is quite thick (12mm i think) and the boxes are held in place by screws edgeways (and slightly inwards) into the plywood. They seem very firm.
R
Not on mine..
Same here. I suspect newer build may have plastic boxes, but this is
1970 and everything except those I've got at are metal.
Nor here, but that may be because we don't use expensive sockets.
You've plastered over the lip? Sounds a bit fiddly to me.
The message from "Dave Plowman (News)" contains these words:
No, you don't plaster over the edge of them.
You can't see them with any of the sockets I've used -- and I've just gone to check. Not a trace. You must have bizarre sockets if a standard dry lining box is visible.
Don't have any dry lining boxes for that reason. But unless you either fit them before skimming or rebate them into the existing skim they are going to show their presence with any standard socket.
But I'm allowed my foibles. ;-)
The message from "Dave Plowman (News)" contains these words:
The message from "Dave Plowman (News)" contains these words:
Of course you're allowed your foibles.
And it's true that old-fashioned flange boxes most certainly did show.
But I've installed considerable numbers of dry lining boxes of various makes under sockets of various makes and switches of various makes and they don't show in any of the instances in which I've installed them.
It would hardly be the end of the world if they did show, but the fact of the matter is that they don't -- with any of the combinations of manufacturers of sockets/switches/boxes that I've used.
So the flange now fits inside the fitting? Don't see how that's possible with some fittings. The type that have basically a flat thin metal faceplate, for example.
Of course it's not the end of the world. I simply don't like these sort of compromises in my house. What others are happy to put up with is their business.
The flange does not fit inside the fitting. It has to be below plaster level or it shows. They are particularly visible with the flatplate switches and sockets as you pointed out.
There are no dry liners in my house apart from the ones used for my mains powered smoke alarms. The smokes look better without a horrible patress and totally cover the liners.
Adam
That's what I thought. And although it might be simple to plaster up to it in a new build I'm not so sure it would be easy to rebate it in and make good on an existing plasterboard wall when adding a socket, etc.
Yes - and of course likely a different colour.
I have used then when adding to a decorated room. But replaced them with steel at re-decorating time.
The message from "Dave Plowman (News)" contains these words:
I'm blowed if I know what strange fittings or boxes some people use. I've checked another three sockets I fitted a few months ago in my aunt's house. No trace of the box visible. Also checked unfitted sockets and switches against unfitted boxes. The fittings all overlapped the flange of the box. And that's simply taking random boxes and fittings.
I'm not trying to sell the idea of using dry lining boxes. However they have a lot to be said for them and I simply haven't come across the problem that you describe, I'm not saying it doesn't occur with ANY combination of accessory and dry partition box, but it hasn't occurred with any of the many combinations that I've used. In every instance the accessory has overlapped the edge of the dry partition box and the flange has accordingly been concealed by the accessory.
With metal flate plate accessories, they very obviously space the fitting off the wall, and from the side, the edge of the cheap plastic flange is visible which rather takes the edge off the flush effect that has been paid for in spades. I.e. they look shit with nice fancy fittings - probably irrelevant with (even nice) plastic fittings where it is all much of a muchness in a white plastic way.
Yup. Dunno about 'spades' - they tend to be about twice the price of a quality plastic fitting. And worth every penny for some applications.
I've just looked at a new el cheapo plastic socket I have lying around and it has ribs running from each corner so I don't see how the dry line box rim can fit inside it.
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