Supplementary Equipotential Bonding Q

[bernardgreen]

but without the earthed metal an appreciable shock would not, in that situation, occur in the first place - and I would personally prefer not to have a shock than to have a shock which an RCD might prevent killing me.

Can you say for certain that a random piece of metal work, one that is not intentionally bonded or earthed by a green yellow cable, is totally free of any connection to ground. ?

 

[JohnW2]

My insurers say "no hot work" in the roof space of ny thatched cottage, and that would almost certainly include anything hot enough to melt solder.

That's obviously up to individual insurers, but anyone who has tried to set fire to anything with a soldering iron might feel that they are being a bit over-cautious.

In any event, that still leaves push-fit fittings as an option. Although, like many, I find it hard to feel confident about them, I am told that that is an "old-fashioned attitude"!

Kind Regards, John

 

[JohnW2]

Can you say for certain that a random piece of metal work, one that is not intentionally bonded or earthed by a green yellow cable, is totally free of any connection to ground. ?

Well, at any point in time one could ascertain that by testing.

However, I agree that nothing is impossible and, as I said, it's down to a an assessment/judgement of which are the more likely of various possible scenarios. I could just as easily ask you if you could be certain that someone would not touch "a random piece of metalwork" at the same time as touching a live conductor in a damaged vacuum cleaner cable, a light fitting or whatever. If that happened, they would get a shock if you had earthed that piece of metal, but little or no shock if they hadn't.

Kind Regards, John

 

[ban-all-sheds]

In any event, that still leaves push-fit fittings as an option.

And compression ones.

Give me those any day over plastic pipes and push-fit. Especially in a location where vermin are known to be more prevalent.

 

[JohnW2]

And compression ones.

Indeed. I forgot to add that.

Kind Regards, John

 

[CEC]

Many thanks for all the replies, really useful stuff.

There appear to be two opinions, utterly at odds with each other, but both could be correct, depending on circumstances. I'm going to go with my electricians view that bonding is not required. As every circuit is protected by RCBOs, the requirements for ADS are met, and as there is no route to earth for the exposed parts of that section of the heating and water system, there is no bonding requirement.

An interesting conversation, thank you.

 

[JohnW2]

There appear to be two opinions, utterly at odds with each other, but both could be correct, depending on circumstances.

That is true, but I think it would be fair to say that the opinion which leads to the view that it is desirable to bond (although not required by regulations) is very much a minority one, generally expressed by only one person in this forum.

I'm going to go with my electricians view that bonding is not required. As every circuit is protected by RCBOs, the requirements for ADS are met, and as there is no route to earth for the exposed parts of that section of the heating and water system, there is no bonding requirement.

That is undoubtedly the majority view, and the view of the regulations. Indeed, as BAS has pointed out, even when supplementary bonding is required (in 'special locations'), the only things that require such bonding are "extraneous-conductive-parts" (metal pipes/whatever liable to introduce earth potential into that special location) - so, if there are no such parts, then there is nothing to bond.

Kind Regards, John

 

[JohnW2]

... Give me those any day over plastic pipes and push-fit. Especially in a location where vermin are known to be more prevalent.

Indeed so. Although I am told that my intuitive concerns about push-fit fittings are unjustified, it is really the plastic pipe which would concern me most in a location such as we are talking about. Furry animals can, and sometimes do (I have seen examples) nibble their way through plastic pipes!

Kind Regards, John

 

[CEC]

Indeed so. Although I am told that my intuitive concerns about push-fit fittings are unjustified, it is really the plastic pipe which would concern me most in a location such as we are talking about. Furry animals can, and sometimes do (I have seen examples) nibble their way through plastic pipes!

I'd agree about plastic, in general, but this is what we've used in our roof space.

https://catalog.uponor.com/en/catal...es/uponor-quattro/uponor-ecoflex-quattro.html

The furry critters will have to go some to get through this stuff. The individual pipes are connected back to the copper pipework via standard compression fittings. All in and connected in a couple of hours. It would've taken a significant amount of time to get copper pipes routed through the roof space.

 

[JohnW2]

I'd agree about plastic, in general, but this is what we've used in our roof space. https://catalog.uponor.com/en/catal...es/uponor-quattro/uponor-ecoflex-quattro.html The furry critters will have to go some to get through this stuff.

Yes, that's clearly a lot more than just basic plastic pipe, but experience has taught me not to underestimate what they can chew through

The individual pipes are connected back to the copper pipework via standard compression fittings. All in and connected in a couple of hours. It would've taken a significant amount of time to get copper pipes routed through the roof space.

Indeed. The speed of installation and small number of joints undoubtedly are significant factors in making plastic plumbing so popular.

Whatever, I personally thk you've made the right decision as regards bonding.

Kind Regards, John

 

[flameport]

There appear to be two opinions, utterly at odds with each other, but both could be correct, depending on circumstances.

BS7671 is perfectly clear on what requires bonding or not.
Many opinions are wrong.

I'm going to go with my electricians view that bonding is not required.

That is the correct answer based on the facts provided.

 

[JohnW2]

BS7671 is perfectly clear on what requires bonding or not.

Indeed it is, and that is, in nearly all cases, and right from the start, what has been reflected by those who responded to the OP here.

Many opinions are wrong.

As a generalisation, that's obviously true. In relation to the particular issue in question, as is usually the case whenever this matter is raised in this forum, there has only really been one dissenting opinion.

When it is simply a case of a particularly cautious person wanting to go beyond the minimum levels of 'safety' required to satisfy BS7671, that's fair enough (although such a person should not really try to impose that opinion on others), but in this case there is an argument that unnecessary bonding can, at least in some situations, decrease safety.

Lest anyone think that 'correct' opinions on this matter are absolute and unchanging, it's worth remember ingthat, whilst BS7671 is, indeed, "perfectly clear on what requires bonding or not", it is not that many years ago that it was equally perfectly clear about totally different edicts about what requires bonding or not!

Kind Regards, John

 

[ban-all-sheds]

I'd agree about plastic, in general, but this is what we've used in our roof space.

https://catalog.uponor.com/en/catal...es/uponor-quattro/uponor-ecoflex-quattro.html

The furry critters will have to go some to get through this stuff.

Don't be surprised if they do.

 

[bernardgreen]

Well, at any point in time one could ascertain that by testing.

Lack of testing was given as the reason for the death of a Miss Shaw https://electrical-testing-safety.co.uk/why-we-test/unlawful-death

The damage to the cable had not been detected because insulation resistance tests had not been carried out properly on the wiring, the jury was told.

The metal stud work was floating, neither earthed nor bonded, so all tests of insulation between Ground / Earth and Live conductors would have given an open circuit result. Had the stud work been earthed / bonded then the insulation testing would have indicated the fault.

 

[John D v2.0]

Had the stud work been earthed / bonded then the insulation testing would have indicated the fault.

IR testing between conductors wouldn't have found it even with bonding, it would have to be IR tested between the conductors and the MET to detect that.