Poll - Ring final circuits with high integrity earthing

[SimonH2]

So if, in another context, a requirement said "dining tables shall have at least 4 legs" you would quibble with someone calling them "table legs".

Fair enough.

That isn't a realistic analogy. It is fairly clear what a table leg is, and I can't offhand think of a practical example where such a differentiation might come up.
But in the case under discussion, there is "a certain amount of debate" about what certain terms mean, and in particular what various arrangements of "actual pieces of material" qualify as. There most certainly IS a difference between "conductor", "protective conductor", and "circuit protective conductor" - enough difference that (IIRC) they have their own definitions in BS7671.

 

[EFLImpudence]

543.2.9

 

[JohnW2]

What about the collection of wires/conductors, screwed connections and metal straps which provide an electrical path from a socket back to the main earthing terminal - do I take it (on the basis of what you've written above) that your view is that, when all those things are taken together, their totality qualifies as "a CPC"?

Yes.

OK - so what if I now install a totally separate collection of wires/conductors, screwed connections and metal straps which provide an electrical path from the same socket back to the main earthing terminal. Do I take it that you also agree that this second set of components also qualifies as "a CPC"?

Kind Regards, John

 

[EFLImpudence]

There most certainly IS a difference between "conductor", "protective conductor", and "circuit protective conductor" - enough difference that (IIRC) they have their own definitions in BS7671.

Too much emphasis is being placed on this. It is obvious.

No definition of "conductor" on its own.
"Protective conductor" also covers "Earthing conductor" and "Bonding conductor" as well as "Circuit protective conductor" but the actual definition is more or less the same and as would be expected.

"CPC" - A protective conductor connecting exposed-conductive-parts of equipment to the MET.
Therefore if a section of a ring CPC (between sockets) is disconnected from the e-c-ps and therefore earth it is no longer a PC (or a ring) but just a conductor or wire.

So, a CPC is made up of several pieces of conductor; not several pieces of protective conductor.

 

[JohnW2]

So, a CPC is made up of several pieces of conductor; not several pieces of protective conductor.

Fair enough. BAS hasn't yet responded to my last question - quite possibly because he's not been around, but also possibly because he has worked out "where I am going" - but I would be interested to hear your responses. I wrote:

What about the collection of wires/conductors, screwed connections and metal straps which provide an electrical path from a socket back to the main earthing terminal - do I take it (on the basis of what you've written above) that your view is that, when all those things are taken together, their totality qualifies as "a CPC"?

Yes.

OK - so what if I now install a totally separate collection of wires/conductors, screwed connections and metal straps which provide an electrical path from the same socket back to the main earthing terminal. Do I take it that you also agree that this second set of components also qualifies as "a CPC"?

Firstly, do you agree with BAS's 'Yes' response to my first question? Assuming you do, what is your answer to my second question?

Kind Regards, John

 

[EFLImpudence]

I wrote:

What about the collection of wires/conductors, screwed connections and metal straps which provide an electrical path from a socket back to the main earthing terminal - do I take it (on the basis of what you've written above) that your view is that, when all those things are taken together, their totality qualifies as "a CPC"?

Yes.

OK - so what if I now install a totally separate collection of wires/conductors, screwed connections and metal straps which provide an electrical path from the same socket back to the main earthing terminal. Do I take it that you also agree that this second set of components also qualifies as "a CPC"?

Firstly, do you agree with BAS's 'Yes' response to my first question?

I do in that it is A CPC but I am conscious that you said "A path to earth" - and to comply, it must be a ring, if we are still talking about a ring circuit.

Assuming you do, what is your answer to my second question?

I do agree - but to comply this also must be a ring.

As I have said before, if this is not the intention then the regulations do not make sense.

 

[ban-all-sheds]

So is that a yes or no to the question ?

Since you seem so determined to miss the point (or are unable to grasp it) I'll give you a very precise answer to that.

543.7.1.203(iii) requires two circuit protective conductors and those two conductors themselves individually need to meet the requirements of 543.7.1.203 which apply to circuit protective conductors.

The question is very simple, really really simple ...

I agree you have written a question in a very simple form. As you have done before.

The problem is that you don't seem to understand that the answer may not be "simple". As it wasn't and you didn't before.

Think of the old "when did you stop beating your wife?" example. It is a very simple question.

Do we agree that 543.7.1.203(iii) requires two protective conductors ?

Yes.

Do we agree that 543.7.1.203(iii) does not require either of those conductors, on it's own, to be a high integrity protective conductor as defined in 543.7.1 ?

I agree that it does not. So may you, but I fear that you do not realise why, so we may not be in agreement about why it does not.

Simple questions, that have simple yes or no answers.

Only simpletons believe that "simple questions" always have "simple answers".

EDIT: So you agree that 543.7.1.203(iii) does not in any way require either of those conductors to be a ring ? Yes or No

Given that the context of this topic is "Ring final circuits with high integrity earthing", no, of course not, because 543.7.1.203(iii) requires that each of them comply with 543.2.9.

It is valid and useful to define what 543.7.1.203(iii) means.

It means that there must be two separate cpcs, each one of which complies with the requirements which would apply to the single cpc of a circuit which did not require a high integrity protective connection. So in the case of a ring circuit, it requires two individual cpcs, and it requires that each of them comply with the requirements for the cpc of a ring circuit.

 

[ban-all-sheds]

BAS hasn't yet responded to my last question

I am getting so, so, SO *(£&$^#@ing sick of this sort of thing:

Whatever it is I've not answered it's not because I'm evading it.

 

[ban-all-sheds]

OK - so what if I now install a totally separate collection of wires/conductors, screwed connections and metal straps which provide an electrical path from the same socket back to the main earthing terminal. Do I take it that you also agree that this second set of components also qualifies as "a CPC"?

Yes.

 

[JohnW2]

I wrote:

What about the collection of wires/conductors, screwed connections and metal straps which provide an electrical path from a socket back to the main earthing terminal - do I take it (on the basis of what you've written above) that your view is that, when all those things are taken together, their totality qualifies as "a CPC"?

Yes.

OK - so what if I now install a totally separate collection of wires/conductors, screwed connections and metal straps which provide an electrical path from the same socket back to the main earthing terminal. Do I take it that you also agree that this second set of components also qualifies as "a CPC"?

Firstly, do you agree with BAS's 'Yes' response to my first question?

I do in that it is A CPC but I am conscious that you said "A path to earth" - and to comply, it must be a ring, if we are still talking about a ring circuit.

I am, at this stage, not talking about any particular sort of circuit, merely attempting to get agreement that the described 'collection of components' (between them, connecting a socket's earth terminal to the main earthing terminal) constitutes "a CPC". Both BAS and yourself seem to agree that it does.

Assuming you do, what is your answer to my second question?

I do agree - but to comply this also must be a ring.

Again, I'm not, at this stage, talking about any particular sort of circuit. We just have a socket and a 'main earth terminal', and we have two totally separate sets of components, each of which you agree is "a CPC", connecting the two. We therefore have "two CPCs".

Now let's start talking types of circuit. If what I've been describing were 'the protective bits' of a radial circuit, then those "two CPCs" would satisfy 543.7.1.203(iii) - so, if it also had 'separate terminals' (543.7.1.204) would qualify as "HIE". Do I take it that you agree?

However, what I've been describing (after my second question) could just as easily be 'the protective bits' of a ring circuit. Those "two CPCs" (which you seem to have agreed exist) are still there, so the arrangement presumably still satisfies 543.7.1.203(iii). It also satisfies 543.2.9, because by joining those two CPCs at the socket (every socket), one has created a ring. I would therefore again say that, as with the radial circuit, if it also had 'separate terminals' (543.7.1.204) it would again qualify as "HIE". I suspect that you will attempt to disagree. FWIW, this is also essentially what the 'Senior Technical Regulations Engineer' said was not only his personal opinion but an opinion with which 'technical committees' (I don't know if that includes JPEL/64) also agreed:

...it has always been my opinion, and discussion in technical committees has agreed with this, that the ring formed by the protective conductor in a ring final circuit is two conductors from any outlet on the ring back to the DB. ... [and then when I asked him if this meant that he believed that a standard ring qualified as 'HIE'] ... I would consider that if your ring final circuit protective conductor connections complied with regulation 543.7.1.204 it would be adequate.

Kind Regards, John

 

[JohnW2]

BAS hasn't yet responded to my last question

I am getting so, so, SO *(£&$^#@ing sick of this sort of thing: .... Whatever it is I've not answered it's not because I'm evading it.

Fair enough - as I said, it was quite possibly that you hadn't been around. I presumed that you would answer eventually, but what EFLI (the only other 'known' No-voter) wrote made me realise that I would also be interested in his answers (which seem the same as yours).

Kind Regards, John

 

[JohnW2]

OK - so what if I now install a totally separate collection of wires/conductors, screwed connections and metal straps which provide an electrical path from the same socket back to the main earthing terminal. Do I take it that you also agree that this second set of components also qualifies as "a CPC"?

Yes.

OK - so you presumably agree that we now have two (totally separate) collections of components, each of which you agree constitute "a CPC". We therefore have "two CPCs". As I've just written to EFLI ....

If what I've been describing were 'the protective bits' of a radial circuit, then those "two CPCs" would satisfy 543.7.1.203(iii) - so, if it also had 'separate terminals' (543.7.1.204) would qualify as "HIE". Do I take it that you agree?
However, what I've been describing (after my second question) could just as easily be 'the protective bits' of a ring circuit. Those "two CPCs" (which you seem to have agreed exist) are still there, so the arrangement presumably still satisfies 543.7.1.203(iii). It also satisfies 543.2.9, because by joining those two CPCs at the socket (every socket), one has created a ring. I would therefore again say that, as with the radial circuit, if it also had 'separate terminals' (543.7.1.204) it would again qualify as "HIE".

I presume that you have some reason for disagreeing with this?

Kind Regards, John

 

[ban-all-sheds]

As I've just written to EFLI .... If what I've been describing were 'the protective bits' of a radial circuit, then those "two CPCs" would satisfy 543.7.1.203(iii) - so, if it also had 'separate terminals' (543.7.1.204) would qualify as "HIE". Do I take it that you agree?

Yes.

Provided, of course, that each of those two CPCs, independent of each other, separate from each other, as individual CPCs, complies with the requirements for the CPC of a radial circuit which does not need a high integrity protective connection.

However, what I've been describing (after my second question) could just as easily be 'the protective bits' of a ring circuit.

They could indeed easily be. And if that collection of "protective bits" was in the form of a ring with both ends connected to the earthing terminal at the origin of the circuit then they would be a CPC. If they are not in that form, etc, then it would be utterly impossible for them to be a CPC, so I'm not sure what the term "protective bits" would then mean.

Those "two CPCs" (which you seem to have agreed exist) are still there, so the arrangement presumably still satisfies 543.7.1.203(iii).

As long as those two CPCs remain two individual, i.e. independent of each other, CPCs, yes.

It also satisfies 543.2.9, because by joining those two CPCs at the socket (every socket), one has created a ring.

And that's where everything falls apart for you, with a ring circuit.

You have, as you say, created A ring CPC. In the singular. One ring.

You have created a single CPC which complies with 543.2.9. 543.7.1.203(iii) requires that you have two individual ones, so you are no longer in compliance with that.

I would therefore again say that, as with the radial circuit, if it also had 'separate terminals' (543.7.1.204) it would again qualify as "HIE".

Not for a ring circuit.

I presume that you have some reason for disagreeing with this?

Yes.

The fact that 543.7.1.203(iii) requires two individual CPCs and the fact that it requires each of them to comply with 543.2.9 and 543.2.9 requires a ring CPC and therefore 543.7.1.203(iii) requires two individual ring CPCs.

If you had ballooning regulations B1 and B2, and B1 said "bags of ballast shall weigh 5kg", and B2 said "balloons designed to accommodate more than 5 persons shall carry 20 individual bags of ballast, each complying with B1", would you argue that that didn't mean you had to carry 20 individual 5kg bags?

 

[EFLImpudence]

However, what I've been describing (after my second question) could just as easily be 'the protective bits' of a ring circuit.

Yes, one ring CPC.

Those "two CPCs"

No, one if it were a ring circuit.

(which you seem to have agreed exist) are still there, so the arrangement presumably still satisfies 543.7.1.203(iii). It also satisfies 543.2.9, because by joining those two CPCs at the socket (every socket), one has created a ring.

Yes, but .203(iii) would require a duplicate if it were a ring circuit.

I would therefore again say that, as with the radial circuit, if it also had 'separate terminals' (543.7.1.204) it would again qualify as "HIE".

Yes, for the two radials.

 

[ban-all-sheds]

I wonder if EFLI will be as annoyed as I am that, having messed up his quoting, the closing tags automatically added by the software to "balance things out" do not get automatically removed after he's fixed his mistakes and they are no longer needed?