Bonding Alkythene/plastic water service?

[kendor]

I may disagree with their pronouncements/policies/attitude/etc., but if a research association says "we have measured the resistance of water in a 15mm plastic pipe and found it to be 115kohms/m", I can't find much basis on which to disagree.

Feel free to add to the list, if you can think of any more reasons, but right now all I can think of is that you disagree because

a) You think they are lying
b) You think they are incompetent
c) You think their instruments were faulty

This is not a case of disputing an opinion or a decision, you are disputing what someone has told you is a fact. You are claiming that the figures published by the ERA are false, in which case you must be able to show why this is, or what evidence you have which leads you to the conclusion that they have published incorrect figures.

you seem to have a knack of making other peoples minds up about things dont you!
I don't subscribe to any of the above things you mention but i base my views on what i consider to be flawed research done under laboratory conditions with fresh water, clean pipes etc and not done in practise using the type of system you'd encounter in your house, lots of people have removed radiators in the past to decorate and the contents are definitely not pure water but contain a sludge (even if inhibitors are used) which is rich in oxides etc and if the test had been conducted properly then the results would be more practical and useful, seems to me that a lot of research is out of touch with really goes on in practise.
Why would they say water can produce a hazard in the first place if it wouldn't? because they could back up the claims using practical means.
when i was at college many years ago we asked the reasons why things were as they were and got good answers that satisfied, what good answer can you come up with why the results you mention have practical meaning in the real world? In other words show me the results that state the composition of the water used and how that relates to water found in practise.

 

[Damocles]

mnb, sorry if you got upset. I understood what you meant by your post, but it did sound like you were asking how to bond plastic pipes. i was very tempted to suggest driving a screw through them. Would make an exellent contact with the water.

It should only take 1m of plastic pipe to effectively insulate a water pipe coming in. I think the regs take a safety first approach because although you might be able to see a plastic pipe coming up through the floor, you can not be sure what might be buried in the concrete.

 

[ban-all-sheds]

you seem to have a knack of making other peoples minds up about things dont you!

No all I said was that was all I could think of for reasons why you might be rejecting the ERAs findings, and I invited you to give your reasons.

I don't subscribe to any of the above things you mention but i base my views on what i consider to be flawed research done under laboratory conditions with fresh water, clean pipes etc

Clearly not a view shared by the ERA or the IEE. And they did test water heavily loaded with inhibitor as well as fresh water.

and not done in practise using the type of system you'd encounter in your house, lots of people have removed radiators in the past to decorate and the contents are definitely not pure water but contain a sludge (even if inhibitors are used)

How much "sludge" is in circulation?

which is rich in oxides etc

Do oxides conduct electricity?

and if the test had been conducted properly then the results would be more practical and useful, seems to me that a lot of research is out of touch with really goes on in practise.

I agree that it would be interesting to see the results of such tests.

Why would they say water can produce a hazard in the first place if it wouldn't?

How about out of ignorance?

because they could back up the claims using practical means.
when i was at college many years ago we asked the reasons why things were as they were and got good answers that satisfied,

That argument does not recognise the fact that over the period of "many years", new knowledge can be discovered which means that what was taught in the past is no longer valid. You can't possibly argue that because what you were taught in the past made sense it can never change...

what good answer can you come up with why the results you mention have practical meaning in the real world? In other words show me the results that state the composition of the water used and how that relates to water found in practise.

I only have access to the same data as you, and everyone else. Would the ERA and the IEE have adopted a cavalier attitude to safety when publishing their advice concerning S-E-B for installations with plastic pipes?

 

[securespark]

Just to add to the debate, my lecturers at college reckoned there was an argument for bonding plastic as the water can carry current.....

 

[Lectrician]

LOL - we could around in circles.

All I will say is...

How many of use have located a fault due to water ingress?

In the last week or so, I have....

....replaced a cent heat zone valve that had blown the central heating fuse in the FCU due to a persistant dripping from a pipe above.

....located a fault on a row of sodium wall washers in a carpark. Found a loose lense (due to barman changing lamps no doubt), fitting full of water.

....located a fault on the array of ELV spot lights in a water fountain. One light had a smashed glass, full of water, blown fuse in transformer. Another transformer (IP65) had a cracked case, and was water logged. RCD tripped.

....located a fault causing the house RCD to trip. Found a damaged masterseal socket outside, full of water.

In short, I think water does conduct. Is it a danger? I would say yes.

In practice, a 1m length of plastic pipe full of water may not conduct very well, but I will be buggered if I would want to hold one end while someone bunged 240v down it.

Either way, I don't give a toss, my job is to wire to the regs, and thats what I will do.

 

[ban-all-sheds]

Just to add to the debate, my lecturers at college reckoned there was an argument for bonding plastic as the water can carry current.....

Well, leaving aside for now the argument over how much current water can carry, I think even kendor would agree that plastic doesn't carry a great deal - did you ever ask your lecturers just how they thought one could bond plastic pipes?

 

[ban-all-sheds]

Either way, I don't give a toss, my job is to wire to the regs, and thats what I will do.

The regs say to apply supplementary equipotential bonding to extraneous-conductive-parts.

Think of the definition of an extraneous-conductive-part.

If you bond to a radiator, or tap, or bath, or short length of decorative CP pipe, that is not an e-c-p because it is supplied by plastic piping, you have not wired to the regs.

 

[Lectrician]

I said I wired to the Regs, meaning exactly to the Regs.

I know how to sup bond, and would never bond something fed from plastic. I would however bond the main gas and main water even if this is fed by plastic, as this is a requirement.

 

[ban-all-sheds]

Apologies - I misinterpreted "Either way, I don't give a toss, my job is to wire to the regs, and thats what I will do." to mean that you didn't give a toss about the arguments around plastic pipes, and you bonded rads etc whatever.

 

[kendor]

the regs are there as guidance, so making an installation above and beyond compliance to the regs is ok.
Ban you mention inhibitor but i'm talking about the lack of inhibitors used, a lot of people out there whether through ignorance or to save money or cant be bothered have very badly maintained systems full of sludge or conductive fluid(water and sludge and whatever else mixed) and this is what tests should have been based on, agreed the levels of contamination would vary but a worse case scenario should have been used.
So i still subscribe to the belief that a hazard CAN be introduced.
You also mention about ignorance on the IEE's part in suggesting that a hazard could happen so likewise what suggests that they have or havn't got it wrong currently and an amendment in the future will happen?

 

[ban-all-sheds]

the regs are there as guidance, so making an installation above and beyond compliance to the regs is ok.

The only trouble is that if a metal item in a bathroom is isolated, and is not an e-c-p, then bonding it is not "above and beyond", it's made it less safe, not more...

 

[securespark]

I have to agree with Ban here. You can go mad and in excess of the requirements and make the installation dangerous, rather than safer.....

Ban, yes, we did ask our lecturers how to do it - they said as you would any other pipe! Their reasoning being that if "live water" contacted the strap, it would run to earth......

 

[ban-all-sheds]

Did these same lecturers ever ask you to go to the office for a long weight?

 

[kendor]

I'm not saying go mad but i disagree with the bonding in this case.