Our water supply is lead, but is connected to plastic straight away, including the stop c*ck. It's behind kitchen units, so not normally accessible.
Does it need bonding to the electricity and gas supplies? They're not very nearby...
i can't see much point in bonding, but I realise that doesn't mean it's not a requirement.
cheers,
rob.
This should be part of the main bonding. The MET (Main Earth Terminal) at your supply point, is the common bonding point for your main earth, water, gas and any other items requiring bonding according to the IEE regulations. This is a safety issue for you and your family; and should be done asap; together with a verification test (loop impedance).
i can believe it's a requirement, but I i don't understand why it's a safety issue. What could arise that could present any danger to anyone? Nothing conducting is connected to the water supply.
Yes, it's a bit silly, but it still needs to be done.
Christian.
Thank christ for that, reading John Maclean's (him from Die Hard) post I was about to evacuate the house as my mains water isn't earthed (yet).
But you're saying it should be safe to enter the house, and I should get it earthed sooner, rather than later.
Jon
The safety issue is a minor one in this case (the on-site guide does give advice for several scenarios with incoming plastic pipes and metal house plumbing etc, but does not seem to explicitly consider the case of metal service with plastic house plumbing).
There is a potential benefit to be had from bonding to the service if you have a PME supply, since it will give you better protection from exposure to dangerous touch voltages on any earthed metalwork in your house should a fault external to the property result in the neutral of the supply becoming disconnected.
It certainly isn't silly. The regulations have been developed because of experience over many years. I myself have come across situations where the main earth to water or gas pipes, have been disconnected deliberately by carpenters etc. because of interference with their work, this is a criminal offence, they don't appreciate the danger they are placing themselves or the householder in. In addition to the reduced risk of shock potentials here, the correct functioning of protective fuses or MCB's during earth fault conditions, is reliant upon the integrity of the earthing system.
It is recommended that householders arrange to have a periodic inspection report on their electrical installation, every 10 years or at change of occupancy.
What would you enter for the code defect on this for a PIR, I would class it as 1.
Whatever. The water pipes are all plastic, so there really isn't much of a safety issue. The regs require you to bond the tiny stub, so you do. There's little benefit, though.
Christian.
There is a posting of the 12th May which also refers to bonding . There is a useful link there which you might like to have a look at . It states that in some circs bonding iro plastic can create a problem rather than solve it .
Do you know the existing Zs/Ze of the OP's installation? How effective is the existing earth bonding? Does the lack of main bond to the water pipe, conform to the regulations? Would the bond to the main water pipe reduce the Zs and make for a safer installation? Is there an increased measure of inbuilt redundancy, with a bond to the water pipe?
Well, it is no different to a plastic piped installation with a plastic main. You really shouldn't rely on your main equipotential bonding to get a decent earth. Yes, you might reduce earth loop impedence a tiny bit, but you should have designed to the maximum allowed supply one anyway and not rely on it.
Indeed, an unbonded metal supply, plastic house installation is probably much safer than the correctly bonded metal throughout installation that is so common.
This is really a non-issue. Yes, the regs say you should bond it. Yes, I would bond it. No, it won't make a blind bit of difference in the scheme of things and I wouldn't go round like some jobsworth sticking immediate danger notices on things and scaring the ladies.
Christian.
You are glossing over the fact that the lead pipe, is an existing efficient means of providing another earth fault path, I disagree with your "tiny bit".
The OP hasn't given any details of the impedance values of the current installation. Is it good, bad or dont you want to know? You can't pontificate from a distance! I reiterate: - it is advisable to have the water pipe bonded; and to have a test carried out on the Impedance values of the installation. What would you do chum?
I would bond the water pipe and test the impedence values of the installation (with the main equipotential bonding removed). I just wouldn't regard it as particularly important or dangerous (provided of course that the system earth was tested and functional). The situation is no different to that of a house with plastic services throughout. It is safer than a house with metal services throughout.
Christian.
I think a code 1 defect applies. However in this case there is no stub of metal for the OP to bond to. The OP said he had lead pipe straight to plastic. The bonding should be done after the stop tap and so he should add a stub and then bond. Not a problem for the OP as this is a DIY group.
Adam
This is the key of my reasoning: - "provided of course that the system earth was tested and functional", I have had problems in the past when doing PIR's, where the supplier's earth is defective and the means of earthing is reliant on the main supplementary bonding. Likewise, with defects in this bonding to gas or water services, largely caused by other trades or diy. Subjectively, as a result of this experience, I treat any issues with main bonding as a code 1 on PIR's: - requires urgent attention. Regards
I accept it is a fault and ought to be flagged as such. If it were my place I would attach a bond to the pipe. However I maintain (as it seems you do too) that the benefit is only one of fortuitous earthing[1]. Given the plastic piping the risk of shock in the property itself under fault conditions is greatly reduced when compared to an unbonded metal installation.
[1] As you highlighted, the importance of this fortuitous earth will depend greatly on the rest of the installation. If it was like my house when we moved in (TT system, ELCB, re-wireable fuse CU, where the *only* earth was to the suppliers side of the gas meter) then it would be of vital importance. On a TN-S install with a Zs of 0.4 ohms, and correctly fitted and tested protective devices it would make little practical difference.
This work on the main bonding to the water pipe would be notifiable to part P. I have sweated copper piping to the mains lead piping in the past; when fitting a new sink, using the blowlamp, moleskin pad, tallow and plumbers metal to wipe the joint. After a few trials and errors; with sprays of water through the porous joint, I finally; and in desperation resorted to peening the lead ball joint all around to stop the leaks, fortunately it worked. There's probably more modern ways of doing such jointing now.
That's irrelevant to the topic of this thread. The purpose of main bonding isn't to improve earthing by lowering Ze; it's to prevent the appearance of any dangerous touch voltage between extraneous- and exposed-conductive-parts under fault conditions. Anyway, Ze should be measured with the main bonding disconnected (or, in the recommended test procedure, measured to the main earthing conductor only, temporarily disconnected from the MET, which amounts to the same thing). And how can you talk of "the Zs of the installation?" - each final circuit will have its own worst-case value (Ze plus the R1+R2 value for that circuit).
Abuse of terminology here: there is earthing and there is equipotential bonding (main and supplementary), but "earth bonding" is not in the vocabulary.
No, unless you can argue that the metal water pipe is not an extraneous-conductive-part - i.e. that it doesn't "introduce a potential." As it enters the building I think that would be difficult to justify, so, yes, it should be bonded.
It will reduce Ze in most cases, but that's not its purpose.
Again, that's irrelevant; it's not redundancy that can be relied on.
Like anyone cares ;-)
In fact wiped joints of this type are no longer permitted. You would have to use a WRAS approved connector like a leadlok or similar.
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