Can cable share the same notch as copper central heating pipes?

tombodge · 27 Jan 2016

I'm rewiring my house and due to it been 100 years old there's been a few people that have had a mess around with it in the past.

At the moment some cable shares the same notch's as the copper central heating pipes for the radiators. These are been removed for the rewire..

Many of the notch's don't follow todays regs (but they have lasted 100 years so im sure there fine)

Is it ok for me to run my 2.5 ring main along these same notchs with the copper pipes. Id rather not add even more notch's because of the above but if i can I will.

I got my information for notchs from this website (first on the google search)

http://www.diydoctor.org.uk/projects/Notching_joist.htm

Im not sure how accurate it is but it doesn't give any spec on how wide a notch can be or how close you can have notch's together. It does seem to give a spec on how close wholes can be though which kind of makes me think its not as important with notch's

Any advice would be great as its stopped me in my tracks tonight and googling isn't helping me out

RF Lighting · 27 Jan 2016

No.

Central heating pipes get very hot and will over time damage the insulation of the cables, also you would need to run much larger cables due to the derating effect the high ambient temperature of the pipe work will have on your wiring.

You also need to consult BS7671 with regards to protection of cables which are run less than 50mm from the top or bottom of a floor / ceiling joist.

Taylortwocities · 27 Jan 2016

Like this

and never like this

tombodge · 27 Jan 2016

RF Lighting said:
No.

Central heating pipes get very hot and will over time damage the insulation of the cables, also you would need to run much larger cables due to the derating effect the high ambient temperature of the pipe work will have on your wiring.

You also need to consult BS7671 with regards to protection of cables which are run less than 50mm from the top or bottom of a floor / ceiling joist.

Thank for the quick reply. I did think it was prity doggy having cables sitting on hot pipes

. Will the BS7671 be available online? How about the specs or regulation on how close I can put one notch next to another one. Or how close i can put a hole next to a notch?

Edit... just reading above post which i think answers my question

RF Lighting · 27 Jan 2016

You'll need to consult the building regs, but the pic you linked to, and the kind TTC has posted above should help you work out where you can drill holes. Holes are much less of an issue structurally than notches are.

BS7671 is available to buy for about £60, but you'll probably have a copy if you're rewiring your house.

Taylortwocities · 27 Jan 2016

tombodge said:
Will the BS7671 be available online?

YES!!

Buy a copy here

I believe that IET provide a digital access by subscription.

But if you mean, is it free to download, then the answer is no. The IET need new marble floors and walls in their HQ every two years, and that sort of thing costs!!!

tombodge · 27 Jan 2016

Yeah that's a great help thank you. Ill get a copy of the BS7671. It still doesn't say how close notch's can be to each other though?

RF Lighting · 27 Jan 2016

It depends on the size of your joists. You'll have to do the maths.

RF Lighting · 27 Jan 2016

Taylortwocities said:
and never like this

Or this

tombodge · 27 Jan 2016

Although that doesn't really matter now. Ive notched the rest of the room so I was going to do the same but after reading that I can drill a hole 100mm plus away in the zone speced above which will work with whats been done already.

Although on this note do I need todo. Or should I do anything about the fact that every single joist doesn't meet regs. Its got a big notch in every joist about 30x30mm big going right down the center of the room with a gas pipe in in. It must of been used for lighting. Its clearly not a problem because its been there 100 years. Its then been wired probably about 40-50 years ago. (the old school red and black cables) also with questionable notching and drilling

tombodge · 27 Jan 2016

RF Lighting said:
It depends on the size of your joists. You'll have to do the maths.

Unless i'm been thick. And that is very possible

the diagram above only shows maths/ spec for notch depth and how far away a notch need to be from a hole. and how far a hole needs to be from another hole. There's no mention of maths for notch width or how close one notch can be to another notch.

Edit so sorry it does.. 100mm apart for both notch's and holes. Ive got it

Working on a floor that's had at least 4 different people working on it all at different times in the past is making it a bit of a nightmare to work around. Its isnt't unsafe like any of the scary pics above though

Iggifer · 27 Jan 2016

Don't think I've ever notched a joist for cables. Don't think I ever will either

ban-all-sheds · 27 Jan 2016

tombodge said:
I'm rewiring my house

You shouldn't be - you don't know anywhere near enough.

Have you applied for Building Regulations approval for the work?

JohnW2 · 27 Jan 2016

Iggifer said:
Don't think I've ever notched a joist for cables.

You must be young

Kind Regards, John

tombodge · 27 Jan 2016

ban-all-sheds said:
tombodge said:

I'm rewiring my house

Click to expand...

You shouldn't be - you don't know anywhere near enough.

Have you applied for Building Regulations approval for the work?

Ive learn't everything ive needed to learn so far and then when I get to the next bit Ill learn that as well. I check ive done everything right down to the smallest detail. Yes Ive been though it all with Building control. and once I have finished I will know enough

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Can cable share the same notch as copper central heating pipes?

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