Main bonding for water pipe
- Thread starter Ohmslaw
- Start date
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Electrically speaking, it should be as close as possible to where the pipe enters the property - which would usually mean 'before' (upstream, 'supply side) of an internal stop valve. However some, maybe many, interpret the regulations as saying that is should be on the consumer's side of the stop valve!
Kind Regards, John
544.1.2 is very clear.
Bonding should be as near as possible to the point of entry to the building…..if there is a meter the connection should be before any pipe branch work…….where practicable, it should be within 600mm of the meter outlet union, or at the point of entry to the building if the meter is external.
The words "stop valve" or "cock" are not mentioned.
Kiriakov, you havent told us
Bonding should be as near as possible to the point of entry to the building…..if there is a meter the connection should be before any pipe branch work…….where practicable, it should be within 600mm of the meter outlet union, or at the point of entry to the building if the meter is external.
The words "stop valve" or "cock" are not mentioned.
Kiriakov, you havent told us
where is it?
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It certainly is to me - and, as I wrote, there is absolutely no doubt that, electrically speaking, bonding should be connected as close as possible to the point of entry. However, you go on to cite the reg:
All true, but you omit from the quote the main bit you see people arguing about. If there is a meter, bonding should be connected to the customer's hard metal pipework. I am not suggesting that I agree, but you will find people arguing (here and elsewhere) that the pipe from the meter to a stopcock is "the water supply company's" - so that the "customer's pipework" must start after the stopcock. ... and please don't shoot - I'm just the 'messenger'.
Albeit in the regulation, the bit (which you again omitted from your quote) about connecting main bonding on the customer's side of an insulating section or insert was obviously written by someone who did not have any understanding of the concept or purpose of Main Equipotential Bonding! ... even on the customer's side of a meter (which it certainly says) is nonsense if it is (or may be) an (electrically) insulating meter!
Kind Regards, John
Does anyone have a water meter indoors?
Yep - I do, and so do both of my daughters, to name but three - so it can't be that uncommon!
In my case, if I complied strictly with the regs, I would have a potentially dangerous situation on my hands. There is a run of something approaching 10 metres of easily touchable metal pipe through my cellar on the supply side of the meter, and the meter appears to be 'electrically insulating'. If I strictly complied with 544.1.2, I would therefore have about 10 metres of easily touchable, un-bonded, extraneous-c-p, travelling past lighting, sockets, bench power tools and goodness knows what else.
Kind Regards, John
Yes internal meter.
I guess I need to relearn bonding, but I thought the idea was that your taps etc were the same potential as your electric appliances. Therefore you don't want the resistance of the meter or cock in the way.
I guess I need to relearn bonding, but I thought the idea was that your taps etc were the same potential as your electric appliances. Therefore you don't want the resistance of the meter or cock in the way.
Oh, fair enough.
I thought that all water and sewerage pipes etc., unlike electric and gas, on your property were your responsibility and that was why the water meters were in the road or pavement or at least outside your property.
I thought that all water and sewerage pipes etc., unlike electric and gas, on your property were your responsibility and that was why the water meters were in the road or pavement or at least outside your property.
The exposed parts of all of your electrical appliances (and, almost inevitably, because of the CPCs to boilers, immersions, CH valves etc. etc., also all your internal pipework, taps etc.) will be at the potential of the earth system of your electrical installation - i.e. the potential of the earth supplied by your DNO if it is a TN supply. That potential may not be the same as true earth potential, particularly under certain fault conditions.
On the other hand, metal water/gas etc. supply pipes entering the property ('extraneous-conductive-parts') usually will be at true earth potential. Hence, if anyone touched a such a supply pipe (or something in electrical continuity with it) and also anything connected to the house's earth system (usually,as above including pipes etc.) they could therefore experience a substantial potential difference, hence a potentially serious shock.
The purpose of Main Equipotential Bonding is to minimise any such potential difference between extraneous-conductive parts and things connected to the houses earthing system. This is done by connecting extraneous-c-ps, as close as possible to their point of entry into the premises, to the MET of the electrical installation.
Kind Regards, John
I'm sure that's how they'd like to do it, and how they do it with new builds and relatively-recently built properties, but it's less straighforward with very old properties (true of all three I mentioned in my family). In fact, in the case of my house, despite their having tried to find out on a number of occasions, Anglian Water do not know how their water gets to my house, so they could not have installed an 'outdoor' meter in pavement (well, grass verge in my case!), even if they had wanted to.
This definitely produces some uncertainties as to 'who is responsible for what'. However, I don't think they can really deny that the meter is 'their responsibility' and hence, by implication, everything upstream of the meter ought to be 'their problem'as well!!
Kind Regards, John
Think back to your school physics lesson. You are aiming to turn your house into a Faraday cage to reduce the risk of electric shock.
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