Running pipe INSIDE floorboard?

[phloaw]

I need to run central heating pipe horizontally under the floorboards of an upper floor. I need to go through only one 75mm wide beam, but I'm wary of boring or notching it, also because that would be quite close to the wall bearing the beam.
So I thought of running an 8mm or 10mm pipe immediately over the beam, by digging a ditch on the lower face of the 18mm floorboard resting on the beam, to accommodate the pipe.
I wanted to know if this makes sense, and how to prevent possible problems such as noises and pipe wear (on the long run). Also: plastic or copper pipe?
Thanks!

 

[Last Plumber]

Why can't you surface run it?
Copper for me, always!

 

[phloaw]

Why can't you surface run it?
Copper for me, always!

I can, indeed. Though acceptable, hiding it would be a bit better, aesthetically

 

[Murdoch]

Using one or some of these would make sense:

Safe Plate Joist Cover - Protects Hidden Wires and Pipes

 

[Ric2013]

You want to avoid drilling through the non-prescribed area of the joist, I'm assuming?

You might want to consider how much a 10mm hole in joist is actually likely to weaken it, though only you can guess how stressed or over-engineered that joist is, and how much you dare to damage it.

What you are suggesting is weird, but it may work. Go for the middle of the board where future tradesmen will expect there may be pipes and cables. In terms of noise, you can either make the mortice in your floorboard a bit loose and wrap felt (or even denim or paper) around the pipe to allow some movement, or consider this part a fixed point and allow the pipe some movement elsewhere (as 10mm or 8mm will always have some flex). I don't see the advantage in plastic pipe.

Using one or some of these would make sense:

Safe Plate Joist Cover - Protects Hidden Wires and Pipes

Out of interest, for cables, should these plates be earthed or are they considered so heavy that a nail is unlikely to penetrate?

 

[Timmy D]

You want to avoid drilling through the non-prescribed area of the joist, I'm assuming?

You might want to consider how much a 10mm hole in joist is actually likely to weaken it, though only you can guess how stressed or over-engineered that joist is, and how much you dare to damage it.

What you are suggesting is weird, but it may work. Go for the middle of the board where future tradesmen will expect there may be pipes and cables. In terms of noise, you can either make the mortice in your floorboard a bit loose and wrap felt (or even denim or paper) around the pipe to allow some movement, or consider this part a fixed point and allow the pipe some movement elsewhere (as 10mm or 8mm will always have some flex). I don't see the advantage in plastic pipe.



Out of interest, for cables, should these plates be earthed or are they considered so heavy that a nail is unlikely to penetrate?

As you know, the cable itself has an Earth, so can’t see a benefit of earthing the plate.

 

[Murdoch]

You want to avoid drilling through the non-prescribed area of the joist, I'm assuming?

You might want to consider how much a 10mm hole in joist is actually likely to weaken it, though only you can guess how stressed or over-engineered that joist is, and how much you dare to damage it.

What you are suggesting is weird, but it may work. Go for the middle of the board where future tradesmen will expect there may be pipes and cables. In terms of noise, you can either make the mortice in your floorboard a bit loose and wrap felt (or even denim or paper) around the pipe to allow some movement, or consider this part a fixed point and allow the pipe some movement elsewhere (as 10mm or 8mm will always have some flex). I don't see the advantage in plastic pipe.



Out of interest, for cables, should these plates be earthed or are they considered so heavy that a nail is unlikely to penetrate?

these plates do not require earthing

 

[Ric2013]

As you know, the cable itself has an Earth, so can’t see a benefit of earthing the plate.

My thought was that if you manage to nail through a live core while missing the earth core (which is possible), the nail itself would be earthed by virtue of passing through an earthed metal capping (there is/was an electrical reg somewhere about 50mm depth or earthed metal covering, presumably where the earthed metal is so thin it provides no mechanical protection?) and so the nail would short to earth, and not pass the electrical load through the person holding the nail.

 

[Murdoch]

My thought was that if you manage to nail through a live core while missing the earth core (which is possible), the nail itself would be earthed by virtue of passing through an earthed metal capping (there is/was an electrical reg somewhere about 50mm depth or earthed metal covering, presumably where the earthed metal is so thin it provides no mechanical protection?) and so the nail would short to earth, and not pass the electrical load through the person holding the nail.

if you hit the live and earth the MCB would trip

if you hit the neutral to earth the RCD would trip

that’s assuming the circuit is rcd protected of course

 

[Ric2013]

if you hit the live and earth the MCB would trip

if you hit the neutral to earth the RCD would trip

that’s assuming the circuit is rcd protected of course

And if you hit the live without hitting the earth? The RCD would trip when you got a shock (assuming, of course, the circuit is RCD protected).

Of course, if the metal plate (not shown in the not-to-scale diagram) is thick enough (regulation 522.6.204 point IV), as you say, it'll be pretty obvious and the carpenter will stop hammering so the situation will remain safe even if the metal plate is not earthed.

 

[Murdoch]

And if you hit the live without hitting the earth? The RCD would trip when you got a shock (assuming, of course, the circuit is RCD protected).

Of course, if the metal plate (not shown in the not-to-scale diagram) is thick enough (regulation 522.6.204 point IV), as you say, it'll be pretty obvious and the carpenter will stop hammering so the situation will remain safe even if the metal plate is not earthed.

Then in this case the nail would be live.

came across this a couple of years ago when a bodging bathroom fitter caught the switched live with a shower cubicle fixing screws which meant when ever the lights were on, the frame of the shower was at 230v

his 2nd error was not to make the earth continuous so if he’s caught The live and earth nothing would have happened.

the homeowner was in her late 70’s and a shock of 230 could easily kill

 

[Ben-gee]

He probably told her she had to shower in the dark, then there’s no problem.