for years I only thought that you could put vertical cables into walls, now I seem to have picked up the idea that you can also put cable in horizontaly. it's diagonally placed cables that need to be avoided.
There would also seem to be a diagram in "Modern Wiring Practice" that shows zones of acceptability going horizontaly as well.
My real life need for horizontal cable is that I am doing my kitchen and want under cabinet lighting. Cabinets are either side of the cooker. Power is only available on one side. So, place a cable in the wall in trunking that'll run between one set of cabinets to the other. I can't get into the roof void above since I would need to remove my toilet, bath and basin - not a popular option!
Yes - horizontal's fine *provided* it's horizontal from a visible electrical fitting. You're also OK if the cable runs deeper than 5cm from the surface; many hold that this applies on *both* sides of a wall, though - so if you've cable running from a lightswitch on one side of a stud wall, by that reckoning you ought to put it *closer* to the side with the switch than the other side where there's no switch. In practice, cables are rarely clipped to the studs - they just drop down the cavity between the plasterboards, passing through a suitable hole in any noggins the builders may have been kind enough to include ;-)
S'fine; you don't need trunking either (sink it into the wall) if it's going horizontally direct from the socket. No-one will mind if, in order to make the horizontal run clear to the vaguely enclued, you choose to put a fused control unit to act as the switch for the cabinet lighting...
You can run cables either horizontally or vertically from a visible electrical accessory such as a switch or socket.
You can also run cables horizontally or vertically in a region 150mm (6") wide adjacent to the ceiling or adjacent to corners between walls. You *can't* run cables in the 150mm region parallel to to floor.
You can't run cables either horizontally or vertically outside the 150mm regions *unless* they go to a visible electrical fitment of some sort. E.g. running a buried cable from behind one cupboard to behind another is not allowed whether vertical or horizontal.
If it is a visible surface run, such as in trunking, you can go anywhere you like. It is only unprotected buried cable that must run horizontally or vertically from a visible electrical fitting. Note that horizontal runs should be avoided when possible, although they are allowed, particularly when the alternatives are inefficient or disruptive. They are particularly useful in kitchen setups, so that you can wire up all the worktop sockets without loads of drop cables.
I have an "exposed beam" ceiling, with no rooms above, just the insulation & slate. I have a solid floor, I have a big room, with rooms off it. A bit like a chapel conversion.
a 150mm wide strip at the top of the room is not possible on one side, as the windows go right up to the ceiling.
This gives me 150mm on one side of the room, to get ring mains, ligthing, smoke alarm cables, door bells, Cat-5, TV, etc etc. I don't really think its enough to get all the cables under the plaster. It gets worse if we have "Mood lighting" and wire each light back to a central point.
Is it possible to put the cables in the floor ? If I put them inside the insulation (inside trunking), and screed over, then there is more than 50mm between the cables and the walk on surface. I'd then run the cables directly up the walls to all the visable items (sockets/switches).
The alternative is to put them into the over-rafter insulation in the roof, which I don't fancy as I have to first fix before the roof goes on.
One possability is to run them under the eves, which is a HUGE gap as my walls are 3 foot thick. I could then bring them through the inner wall at the top, and vertically down to the sockets/switches or up in the insulation to lights in the ceiling. I know I can't join the cables under the eves. Mice damage somewhat worries me with this idea.
Finally if there is a spakie in North Wales who fancies being a paid consultant, then drop me a line.
Its true actually, horizontal isnt actually allowed, although its found in practice, done by home diyers etc. It is allowed for wiring to be upto 3.5 degrees off vertical though, thankfully.
So on new builds, where the wiring is properly inspected, there are 2 way to do things:
have all sockets light switches and lights above or below the CU, but not to the side. This works for small flats, but is impractical for whole houses.
Run the wires down far enough to use the 3.5 degs allowance to get them to where theyre going. This typically means drops of 50-80 feet underground. No wonder diyers sometimes disobey the rules.
No need at all. Drop 10 feet, then go back up again at an equal 3.5 degree angle the other way. You don't need to dig down if you do this repeatedly. You need to watch the bending radius where you change direction, of course. This method is known as 'taking the P'.
Well yes, true in theory, but thats not how its done normally, as we know. Since the electric mole diggers can not change direction with a small enough radius to satisfy part P bending radius requirements, and nor do they have the level of complexity of control to make these zigzag tunnels, so if you take the p you'd have to do it by hand. Its difficult, hence the name taking the p. Onsite newbies always got taken by that one.
The practical way is to send the moles straight down from the 2 ground points until they meet. Also of course a zigzag conduit is impossible to thread.
While what you say is true in theory, one has to be practical about it.
I wont even get started on high rise buildings, where you need to get to sockets without running cables into the flat below... thank god for the 1908 P Wall Act eh.
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