Redundant copper pipe as conduit?

[ATTQ]

I've seen a few not entirely conclusive and almost 20 year old threads so thought I'd ask again

I've the floor up in 2 bedrooms but hoping not to on the one in between them. There are 2x 22mm mostly straight old water pipes running under the middle bedroom I could use rather than try to get them out and thinking its better protection than nothing. I can solder tabs on for earthing the pipes. They both have a wide radius S bend at one end preventing me pulling them through and using proper conduit but i'd hope the bend is ok for cable to get through.

The cables I need to run are radials i want to drop down for a kitchen and a workshop where I want a 16amp socket for welding and plasma cutting.

Run is about 15m to kitchen and 20m to workshop. 4mm T&E to each room?

I'll be getting competent help at some point but just want to make sure the wires are hanging out at both ends to be done properly with when i get to it. Starting think i should get the help in now to discuss but they aren't easy to find are they and maybe not very interested unless they know what I'm committing to.

Do any electricians offer themselves paid for an hour of consultation before the job? I don't want to feel like I'm taking the mick and I want serious consideration of the job

 

[JohnW2]

I've the floor up in 2 bedrooms but hoping not to on the one in between them. There are 2x 22mm mostly straight old water pipes running under the middle bedroom I could use rather than try to get them out and thinking its better protection than nothing. I can solder tabs on for earthing the pipes. They both have a wide radius S bend at one end preventing me pulling them through and using proper conduit but i'd hope the bend is ok for cable to get through.

There's no requirement for any 'mechanical protection' of cables under floors, so there's no problem with what you propose, - although it would be desirable (as you propose) to earth the copper pipe. Whether there is any point, given that no other under-floor cables would be similarly 'protected', is a different matter, but if it would be convenient to do it as you propose,, I see no reason why not.

Kind Regards, John

 

[ATTQ]

There's no requirement for any 'mechanical protection' of cables under floors, so there's no problem with what you propose, - although it would be desirable (as you propose) to earth the copper pipe. Whether there is any point, given that no other under-floor cables would be similarly 'protected', is a different matter, but if it would be convenient to do it as you propose,, I see no reason why not.

Kind Regards, John

It was just old threads make me think i should earth it but they were so old maybe before it was automatically assumed to be RCD protected. I noticed its just bare cables under the floor normally. This idea was mainly to make use of whats there to feed the cable through hopefully easier than without though i've got a set of poles at the ready i think this pipe will be easier.

The only thing though is it comes out in what will be a bathroom. down behind the wall next to a toilet and under the floor across including under a shower. All of that will be after its exited the copper though. I just need to make sure the wires are coming out from the room over the CU before i finish that and move on

 

[Jurassicspark]

I can solder tabs on for earthing the pipes.

Not without knowing where the pipes originate from, I wouldn't want to earth those pipes.

 

[ATTQ]

Not without knowing where the pipes originate from, I wouldn't want to earth those pipes.

Can you explain that for an electrically illiterate?

I can see both ends of the pipe, they were for a bath from a storage tank and I removed both. still curious to know what you were saying though.

 

[Jurassicspark]

Can you explain that for an electrically illiterate?

I can see both ends of the pipe, they were for a bath from a storage tank and I removed both. still curious to know what you were saying though.

Think about it.

The pipes (in your case) does not form part of the protective earth. There will be no point of earthing it.

If you didn't know where the pipes came from then earthing (without it connecting back to the MET) it can result in voltages appearing on the pipework or anything connected to it under a fault condition.

Nothing will disconnect the power and someone will be dead by touching the pipe.

 

[ATTQ]

Think about it.

The pipes (in your case) does not form part of the protective earth. There will be no point of earthing it.

If you didn't know where the pipes came from then earthing (without it connecting back to the MET) it can result in voltages appearing on the pipework or anything connected to IT. Nothing will disconnect the power and someone will be die touching it.

ah i wasn't thinking of connecting the cables earth to the pipe, but the pipe to The Earth in case the cable cut through, somehow chaffed etc. is that still wrong tho ?

 

[Jurassicspark]

u ah i wasn't thinking of connecting the cables earth to the pipe, but the pipe to The Earth in case the cable cut through, somehow chaffed etc. is that still wrong tho ?

Same thing.

Cables develop a fault and touches the pipe. Your earth wire won't be doing nothing.

If the pipe doesn't connect back to the main earth then earthing it would be unnecessary.

 

[ATTQ]

I did half a plumbing YTS scheme in the late 80s. Taught me all i needed to know about knowing nothing about electrics and despite trying its still a dark seeming art

 

[ATTQ]

Same thing.

Cables develop a fault and touches the pipe. Your earth wire won't be doing nothing.

If the pipe doesn't connect back to the main earth then earthing it would be unnecessary.

lol what. If I run a wire from the pipe to earth wont that drain off all those electrons or whatnots safely down to the earth if the live wire touches it? isn't that the point of the earth wire and it normally doesn't do anything much?

This is how I always feel talking to my accountant "I didn't think I was an idiot but now i'm not sure"

 

[ATTQ]

If the pipe doesn't connect back to the main earth then earthing it would be unnecessary.

But isn't the issue that if the live wire touches the metal all 5 meters of pipe is live so someone might touch it and get electrocuted if the electric isn't channeled to the earth. come on this must be the case isn't it? Its all irrelevant seeming these days though isn't it with RCDs? I was a bit shocked to find this house doesn't have any RCDs so far but that was just one of a few reasons it was relatively affordable. This cable wont be going live until the new CU is fitted

 

[JohnW2]

It was just old threads make me think i should earth it but they were so old maybe before it was automatically assumed to be RCD protected.

As I said, there would be no 'need' ('requirement') to earth the pipe.

In general, it is undesirable to ('unnecessarily') earth any touchable metal that would not otherwise be connected to earth. That is because in the event of someone touching something live, they will only get a serious shock if they simultaneously touch something else which is earthed (or connected to neutral). However, in your case it seemed that the pipe would be entirely below the floor, and therefore not usually touchable, so that would not really be an issue.

The only thing though is it comes out in what will be a bathroom. down behind the wall next to a toilet and under the floor across including under a shower. All of that will be after its exited the copper though

If the cable 'passes through' a bathroom, it is required to be RCD-protected, but I assume that will be the case.

 

[JohnW2]

If you didn't know where the pipes came from then earthing (without it connecting back to the MET) ....

Can you explain exactly what you mean by "earthing (without it connecting back to the MET)"?
I presume the OP was talking about connecting the pipe to a CPC - which,in turn, would be 'connected back to the MET'.

it can result in voltages appearing on the pipework or anything connected to it under a fault condition. .... Nothing will disconnect the power and someone will be dead by touching the pipe.

What you were thinking of .... a 'fault' on what, and a voltage relative to what?

 

[ebee]

What does concern me a little more perhaps is could it be construed as misleading.
Some might think that it is reasonable for some people to realise that a conduit might contain live wires yet not expect a copper pipe to contain live wires, they could both offer a degree of mechanical protection but one might be expected and the other might not be expected, by some - having said that then how many people actually know where our permitted wiring zones might be or not and will some folk still blatantly drill or nail into them with total disregard?

 

[ATTQ]

What does concern me a little more perhaps is could it be construed as misleading.
Some might think that it is reasonable for some people to realise that a conduit might contain live wires yet not expect a copper pipe to contain live wires, they could both offer a degree of mechanical protection but one might be expected and the other might not be expected, by some - having said that then how many people actually know where our permitted wiring zones might be or not and will some folk still blatantly drill or nail into them with total disregard?

its a good point but I think most wouldn't cut into a water pipe any more than an electrical one unless quite sure they know whats going through it by finding at least one end, which would show the wire. As for as danger goes is that even a worry once the wires are RCD protected? Not sure if its wise to put total faith in them or are they considered entirely reliable protection?