Chasing cables up stairs.

[lasors]

I'm doing the prep work prior to getting an electrician in to rewire our house. The previous owner had an electric shower put in to the bathroom at the top of the stairs. There were no modern electrics at this point, so the cable was surface mounted down the wall of the stairs (at the top corner with the ceiling) to a small consumer unit, installed purely for the shower, at the bottom of the stairs

I want to bury the cable in the wall. Is it ok to just chase it in where it is now, as it's a horizontal and diagnonal run, albeit not across the centre of the wall. I can't think of another way to do it other than run it through the loft space, but this means dropping it down through the master bedroom. It's all brick internal walls, there are no cavities.

Thanks.

 

[ban-all-sheds]

I'm doing the prep work prior to getting an electrician in to rewire our house.

The only way that will work is if you find your electrician first and agree with her in advance what work you can do yourself.

She will be the one having to certify that the work she did, including the design, complied with the Wiring Regulations and the Building Regulations.

All questions about where and how to route cables, for example, must be addressed to her, and everything you do must be under her supervision and direction.

I want to bury the cable in the wall. Is it ok to just chase it in where it is now, as it's a horizontal and diagnonal run, albeit not across the centre of the wall.

NO!

• http://www.voltimum.co.uk/files/gb/attachments/niu/l/attachments/c5-43.pdf
• http://web.archive.org/web/20061110111450/http://www.niceic.org.uk/downloads/concealedcables.pdf
• IEE article
• IEE Article on 17th Edition requirements for concealed cables.

But as long as you refer to your electrician for all such questions and guidance you won't go wrong.

 

[ColJack]

ah.. the much debated "pitched roof" safe zone question..

as it's within 150mm of the ceiling it should be a safe zone, odds are you're not going to nail anything that close to the ceiling ( except for coving.. ) so it should be safe..
but then again all of the pretty pictures only show a regular box shaped room so people tend to say no you can't since it clearly says you can't run diagonally ( withouth mechanical protection ), but that refers to between two, or to and from an accessory.

 

[lasors]

Thanks for the quick reply.

I'm not really doing anything other than lifting floor boards, cutting chases and sinking new back boxes where we require plugs. I scanned all the walls and marked anything detected beforehand. The kitchen is now out and the furniture out of the way.

If the cable can't run in the wall down the stairs, can you suggest where it's likely to go? Is it because the cable runs on the diagonal of the stairs that it doesn't count as being in the 150mm safe zone?

 

[lasors]

ah.. the much debated "pitched roof" safe zone question..

as it's within 150mm of the ceiling it should be a safe zone, odds are you're not going to nail anything that close to the ceiling ( except for coving.. ) so it should be safe..
but then again all of the pretty pictures only show a regular box shaped room so people tend to say no you can't since it clearly says you can't run diagonally ( withouth mechanical protection ), but that refers to between two, or to and from an accessory.

You beat me to it ColJack! So is it a yes or a no, with regard to the regs?

 

[ban-all-sheds]

I didn't interpret this

it's a horizontal and diagnonal run

as meaning a sloping ceiling, but you might be right.

It's all brick internal walls, there are no cavities.

Chases for cables can be made in these.

 

[ban-all-sheds]

You beat me to it ColJack! So is it a yes or a no, with regard to the regs?

 

[ColJack]

I didn't interpret this

it's a horizontal and diagnonal run

as meaning a sloping ceiling, but you might be right.

you're not reading the right bit BAS..

.. so the cable was surface mounted down the wall of the stairs (at the top corner with the ceiling)...
I want to bury the cable in the wall. Is it ok to just chase it in where it is now?....

 

[ColJack]

do we take it that the route back to the CU is through the master bedroom then?
it might ba an idea to provide a void for the sparky to run his wires in..
a couple of 2x2 battens screwed vertically to the wall where the cables will run and then plasterboard that wall afterwards..

 

[ban-all-sheds]

I've got stairs, walls, ceilings, top corners.

All orthogonal.

And I could imagine a cable route that ran horizontally and diagonally but was not across the centre of the wall.....

 

[lasors]

The route doesn't go through the master bedroom, no.

I'll get a couple of photos and put them up later.

 

[lasors]

Some photos. As you can see, it's only a small run of diagonal, but it is by definition in a safe zone. You can just see the consumer unit it at the bottom of the stairs, bathroom is behind camera to the left.

My first chase, quite neat if I do say so myself Note the seemingly random changes between brick and block. It's like that on the other chases as well, follows no pattern. Just what was left over?

The old plugs in the living room go upstairs via the chimney.

 

[ban-all-sheds]

Some photos. As you can see, it's only a small run of diagonal, but it is by definition in a safe zone. You can just see the consumer unit it at the bottom of the stairs, bathroom is behind camera to the left.

OK - my apologies - I did misinterpret what you meant by diagonal. 522.6.6(v) is quite clear about the 150mm zone at the top of a wall, nothing about it having to be horizontal.

If you're going to chase the cable in on that route make sure you allow for the minimum bending radius.

My first chase, quite neat if I do say so myself

Yup.

Did you use a machine? If not you might like to think about buying or hiring one, as it doesn't look as though you need to worry about getting dust on the white shagpile or leather sofas just yet. If you make the light switch drop chases large enough for steel conduit you can avoid having to have the lighting circuits on an RCD if you want.

See //www.diynot.com/forums/viewtopic.php?p=1116193#1116193

Note the seemingly random changes between brick and block. It's like that on the other chases as well, follows no pattern. Just what was left over?

Probably.

The old plugs in the living room go upstairs via the chimney.

Still counts as concealed, and on dodgy ground, zone-wise, as is the cable running up to the FCU next to the timer.

 

[lasors]

I did use a machine, I bought the cheapest one from B&Q Nextday, which made things very easy and much faster than doing it all with the bolster. Even with a vacuum attached the dust was incredible. I'll sell it on when the job's done and it'll still be cheaper than hiring one.

What's the advantage of not having the lights on an RCD? Purely the cost of the unit? I take it I don't need steel conduit for the runs under the floorboards upstairs, just in the walls?

There's a 2-way switch for the lights in the entrance hall and landing, would they go on the upstairs or downstairs ring?

 

[Steve]

I wouldnt have expected a wall chaser to give such perfect results. I would have expected significant chipping of the surface plaster. Did you use anything to guide it? Or just freehand against a pencil line?