No, it is now effectively connected to the PEB.
Of course it is supplementary (additional) bonding.
How about "pointless and not worthy of consideration"?
Current Earth Bonding Regulations
- Thread starter Bucks
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If 1666Ω is to be the threshold over which something is not effectively connected to the MEB, then should it not also be the threshold over which something is not effectively connected to Earth and therefore not effectively able to introduce a potential and therefore not effectively an extraneous-conductive-part?
I'm not really playing Devil's Advocate but, rather, am pointing out that the regs themselves do not quantitatively define what constitutes an extraneous-c-p. They merely define it as a conductor which is "liable to introduce a potential (usually earth potential) - and, as I have pointed out, a conductor is 'liable to introduce a potential' even if its resistance (to earth or whatever) is 1MΩ or more - albeit that 'introduced potential' would then be essentially harmless!
I agree that it would be perfectly reasonable to define an extraneous-c-p in terms of the current which could flow through a person to earth through that conductor under worst-case fault conditions (e.g. your >23kΩ criterion) - but the regs do not appear to do that (even if some guidance documents do).
Kind Regards, John
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Well, it's certainly bonding, and it's certainly not Main Bonding, so one could sympathise with what you're saying - but, in the absence of a connection to CPCs, it does not seem to satisfy the definition in 415.2.1 for 'supplementary bonding' - so, as I've implied, maybe we need (BS7671 needs) a third term?
"Pointless" is certainly correct in terms of what plumbers often do, but what you are describing above is essentially the same (connecting two pipes together without also adding a connection to CPs) - but, in your case, not pointless!
Kind Regards, John
Why not?
How can you have a grey area?
Surely something is either effectively connected or it is not effectively connected. It's binary.
When my new CH boiler was installed they "cross bonded" (for want of a better term) all 6 pipes into the boiler, and when I asked them why, they said "our company electrician says we must"
No. A connection to earth which falls far short of representing 'an effective connection to the MEB' (per that definition) could represent a serious hazard.
That is, I presume, why, per the guidance figures EFLI is citing, it is being suggested that something should be regarded as an extraneous-c-p if its resistance to earth is less than 23kΩ - representing (if one ignore's the person's impedance) a 10mA current flowing through a person who is 'connected' between a 230V source and that conductive part.
Kind Regards, John
That's ridiculous; 415.2.1 is not a definition. See NOTE 3 above and 415.2.2
Ridiculous again.
So, the only part of supplementary bonding which may not be omitted ceases to be supplementary bonding.
That's what they always say!When my new CH boiler was installed they "cross bonded" (for want of a better term) all 6 pipes into the boiler, and when I asked them why, they said "our company electrician says we must"
Kind Regards, John
Ridiculous or not, that note does not alter the fact that 415.2.1 says "Supplementary equipotential bonding ... shall be connected to the protective conductors of all equipment including those of socket outlets". Perhaps more to the point, in relation to bathrooms etc. (the only situation in which supplementary bonding rears its head), 701.415.2 (a supplement to 415.2) re-iterates that any/all supplementary bonding in a bathroom has to be connected to "he terminals of the protective conductor" of each circuit in the room.
I don't completely understand that.
Kind Regards, John
Yes, 'effectively connected' (in the sense of facilitating the operation of a 30mA RCD in the presence of a 50V touch voltage) or not is binary.
However, in terms of the general definition of an extraneous-c-p (for which one cannot assume that there is RCD protection) much higher resistances to earth could still represent a hazard.
It's not a 'grey area' - it's two different situations.
Kind Regards, John
Only if required.
I feel you are taking the mick.
We are talking about supplementary bonding being omitted when RCD protection is in place.
This is the same as saying that, despite the RCD, supplementary bonding IS required where the resistance between parts is > (yes >) 1666Ω. Where this is applicable to only one pipe means that the single conductor required IS supplementary bonding.
In my example of this being caused by a plastic pipe connection then a conductor bridging that connection would achieve the same compliant result.
This conductor is therefore supplementary (additional) bonding.
Yes, but you are proposing to describe as 'supplementary bonding' the connection you propose to install (just connecting two pipes) in order to allow (other) supplementary bonding to be omitted. Are you saying that there are two types of 'supplementary bonding', one which does, and the other which doesn't, require a connection to CPCs?
Not at all. I'm confused ....
Indeed we are.
Fair enough - but, as I've said, if this "IS" supplementary bonding, why is it immune from the requirement that it should be connected to "the terminals of the protective conductor" of each circuit in the room?
It's certainly 'additional' bonding - but, as I keep saying, it does not appear to satisfy the BS7671 requirements for 'supplementary bonding'.
This whole discussion arises because you are insisting on calling your connection between two pipes (and nothing else) as 'supplementary bonding'. If you called it something else, I think we would probably be totally in agreement
Kind Regards, John
No, the CPCs will be within the 50/Ia limit and will not require supplementary bonding.
But that only applies IF the item requires supplementary bonding.
415.2.1 is dependent on 415.2.2
What else is there to call it?This whole discussion arises because you are insisting on calling your connection between two pipes (and nothing else) as 'supplementary bonding'. If you called it something else, I think we would probably be totally in agreement
It is additional; that is all supplementary means.
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