How to fit metal capping?

[bonebill]

Will be doing some wiring.

Thinking about the cables which come down from ceiling level to switches and sockets. It will be either on a wall where the plaster has been removed en masse, or in a chased-out channel, so in either case on the bare brick or block work.

It looks like it would be a good idea to install capping. It looks like metal capping is a better idea than plastic capping.

Was wondering how to fit such capping. I was thinking of some kind of fixing like nails or screws.

But thinking about it, I would have a strip of undrilled metal capping and a hard brick wall.

Looks like I'd have to drill the capping, drill the brickwork, and use plugs and screws. Sounds like a hell of a lot of fiddly work. I can't see a pro messing around doing that.

Feels like I've gotten something wrong somewhere along the line.

Any suggestions?

No More Nails?

 

[andy]

cut capping about 2-3CM longer than what you need. fold over each end using pliers. depending on how hard the wal is, use nails into the concrete, just to the side of the capping. once there in enough, hammer over, onto the side of caping to hold in place. if too hard to out nail in, drill 5.5mm hole and put a wall plug in. hammer nail between wall plug and brick. simple.

 

[dingbat]

Drilling and screwing is not so hard. Hold the capping in place and mark two spots, one either side, then use a 6mm masonry bit and red plugs and fix the capping with pan-headed galvanised screws and M6 washers. Once you've got it fixed in one spot you can easily drill either side of the capping where necessary and fix as many screws as you need. (Oh and do turn the cut ends as andrew suggested) Most capping runs can be secured with 4-6 screws - 5-10 mins for each length.

Or, buy a masonry-grade nail gun and do the job in seconds!!

 

[bonebill]

cut capping about 2-3CM longer than what you need. fold over each end using pliers. depending on how hard the wal is, use nails into the concrete, just to the side of the capping. once there in enough, hammer over, onto the side of caping to hold in place. if too hard to out nail in, drill 5.5mm hole and put a wall plug in. hammer nail between wall plug and brick. simple.

OK. So what you're saying is drive the nails in until there is a short length exposed, and then bend the end over on to the capping.

But I don't follow you on the bit about

cut capping about 2-3CM longer than what you need. fold over each end using pliers.

What do I get out of doing this?

 

[breezer]

stops it chaffing the cables

 

[bonebill]

Drilling and screwing is not so hard. Hold the capping in place and mark two spots, one either side, then use a 6mm masonry bit and red plugs and fix the capping with pan-headed galvanised screws and M6 washers. Once you've got it fixed in one spot you can easily drill either side of the capping where necessary and fix as many screws as you need.

Ah. So at no point does the screw go through the capping. You can get away with just having the side of the screw head and washer gripping the capping because there is a screw either side of it. OK.

(Oh and do turn the cut ends as andrew suggested)

OK so the purpose of that is to lose the sharp edges where the capping has been cut. (I guess you have to saw off lengths with a hacksaw.)

Most capping runs can be secured with 4-6 screws - 5-10 mins for each length.

4-6 screws would be 2-3 fixing points. OK sounds reasonable.

 

[ban-all-sheds]

Why do you want to use capping in the first place?

 

[andy]

OK so the purpose of that is to lose the sharp edges where the capping has been cut. (I guess you have to saw off lengths with a hacksaw.)

get some tin snips. it can be very difficult with a hacksaw (altho you could use a junior).
fold the ends to take away the sharp edges so the cable doesnt get damaged. also make sure the cables are flat thruout the drop (i.e not twisted)

4-6 screws would be 2-3 fixing points. OK sounds reasonable.

depending on length, put 2 at top and 2 at bottom. put some in the middle in needed. aslong as its helf firmly it should be ok

 

[paulh53]

How about these "Capping Nails"?

 

[mapj1]

You might like to consider oval conduit if the plaster skim will cover it, the the difference in price is small but if it ever needs to be re-threaded it is much, much easier. (the cable is not trapped against rough brick, and there is no risk of plaster toothpasting between wall and capping.)
In many cases, in terms of replacement after nailing up a picture or whatever, capping offers no advantage over plastering the wires in direct, as in both cases the plaster has to be broken out.
The same mounting considerations apply, and screws and penny washers, nails, loops of wire, dobs of mastic, and (my personal favourite) metal buckle clips with masonry nail (saren type, at 8 quid a hundred) can all be used to make a secure holding, before the plasterer does his stuff. (though in a chase, all this is often overkill, as the tubing can simply be wedged against the sides)
It is an interesting side note that capping is deprecated in some continental countries, and closed side conduit preferred, for the reasons of replacement and inspection. (for example in Germany new sockets in areas subject to condensation (kitchens, bathrooms) should be conduit fed from above, the idea being there is no risk of the cable sitting in a pool of water, and if damaged in any way , more slack can be pulled through the tube from above. I believe the French also favour conduit in many places we would not bother.)
In any case, whatever you use, stick to the lines of least surprise (permitted routes) as far as possible, and use earthed metal capping or conduit if you can't.
regards M.

 

[ban-all-sheds]

One thing to watch, which I'd never thought of, but I think it was someone on the IEE site that reported it - he'd installed acessories using oval conduit, upstairs, and he'd taken the ends of the conduit up through the loft insulation, so that the open end was above it.

He found that warm air rose up the conduit, and when it encountered the cold bit at the top condensation formed which then ran down the conduit into the back boxes....

 

[dw3101]

do they actually make any metal patresses that 20mm oval conduit fits in??

David

 

[ban-all-sheds]

No - you either have to soften the end with a bit of heat, and make it round, or what I find works a treat are Masterseal push-fit conduit entries:

http://www.mkelectric.co.uk/products/item.asp?itemid=6134&rangeid=1031

As they are soft, and when you squeeze the top they elongate and oval conduit slips in nicely. Trouble is they aren't the cheapest of items...

 

[bonebill]

Why do you want to use capping in the first place?

Didn't fancy the idea of plastering straight onto the cable. I know modern plaster is nothing like as bad as the old lime plaster, but I didn't fancy the idea of having even modern plaster in contact with the cable.

Also metal capping might give someone a clue before they accidentally poked something through it. Not that I would be relying on this of course. I was only thinking of having capping in the "safe" zones anyway, but not everyone thinks before doing things.

But it does look like capping might not be quite as good of an idea as I first thought. I will have to consider plastering straight over the cable, and also using conduit.