High integrity earthing and ring final circuits.

[ban-all-sheds]

I'm not disputing the fact you can use a ring CPC on a radial, this is generally for when the CPC is smaller than required by 543.7.1.3 (i) or (ii).
If you decide to want to install a conductor sized in accordance with 543.7.1.3 (i) or (ii) then 543.7.2.1 (iii) will be complied with hence there is no requirement to form a conductor of those larger sizes into a ring conductor.

So ignore the size that the cpc is, or might be, and just consider its topology.

The diagram could show, according to you, either the single protective conductor for a radial, connected as a ring (543.7.2.1 (ii)(a)) or two individual protective conductors (543.7.1.3 (iii)).

And you don't see any consistency problems there?

I don't like the way the OSG 16th ed changes the wording of the regs!

It doesn't - it is not a BS publication. It neither defines nor amends a published national standard. And it has a disclaimer to say that it doesn't ensure compliance with the published national standard.

 

[Spark123]

The diagram could show, according to you, either the single protective conductor for a radial, connected as a ring (543.7.2.1 (ii)(a)) or two individual protective conductors (543.7.1.3 (iii)).

And you don't see any consistency problems there?

In either case there are two protective paths via protective conductors for current to flow. Wether it be a radial with a ring CPC for compliance with 543.7.1.3 (iii) or a ring with a ring CPC for compliance with 543.7.1.3 (iii).

I don't like the way the OSG 16th ed changes the wording of the regs!

It doesn't - it is not a BS publication. It neither defines nor amends a published national standard. And it has a disclaimer to say that it doesn't ensure compliance with the published national standard.

Yep, I was meaning the wording used in the OSG p60 is along the lines of duplicate protective conductors for compliance with 607-02-04.

 

[mattylad]

folks, wheny ou have finished this highly quoted debate, can someone please summise it in simple statements so that us plain ol DIY'r get to know whatthe outcome is & actually means?

 

[ban-all-sheds]

The diagram could show, according to you, either the single protective conductor for a radial, connected as a ring (543.7.2.1 (ii)(a)) or two individual protective conductors (543.7.1.3 (iii)).

And you don't see any consistency problems there?

In either case there are two protective paths via protective conductors for current to flow.

There you go again.

Will you please quote the part of the regulations which talks about protective paths.

And then will you please answer the question about the inconsistency that arises when you state that the diagram can show either one single protective conductor (or path) or two individual protective conductors (or paths).

And while you're doing that, could you explain how your method of counting and identifying two individual protective conductors fits with the concept of a multicore cable containing both individual protective conductors? And how one of them could be the braid or shield etc?

If what is meant by this part is not two individual conductors in the way that I've been saying all along, but what is meant is two paths by virtue of how you connect up individual segments of a single cpc, or what is meant is the presence at any point of two individual segments of a single cpc, how could one cable core and one cable sheath be involved?

Yep, I was meaning the wording used in the OSG p60 is along the lines of duplicate protective conductors for compliance with 607-02-04.

1) 607-02-04 is from an old version of the regulations

2) Apart from references to other regulations, 607-02-04 is worded the same as 543.7.1.3.

 

[ban-all-sheds]

folks, wheny ou have finished this highly quoted debate, can someone please summise it in simple statements so that us plain ol DIY'r get to know whatthe outcome is & actually means?

I fear that the outcome is that Spark123 will persist in ignoring the contradictions thrown up by the definitions he uses, he will persist in trying to justify his definitions with words which are not used to describe the requirements, and will persist in refusing to simply read what the regulations clearly say.

And he will persist in ignoring and evading every single question I ask him which has to do with his inconsistencies....

 

[Spark123]

Will you please quote the part of the regulations which talks about protective paths.

It doesn't, but if you don't have conductors you don't have paths for current to flow.

And then will you please answer the question about the inconsistency that arises when you state that the diagram can show either one single protective conductor (or path) or two individual protective conductors (or paths).

Which part of 543.7.1.3 does 543.7.2.1 (ii)a comply with? When you form a radial complying with 543.7.2.1 (ii)a into a ring does it provide two individual protective conductor paths so it complies with 543.7.1.3 (iii)?

And while you're doing that, could you explain how your method of counting and identifying two individual protective conductors fits with the concept of a multicore cable containing both individual protective conductors? And how one of them could be the braid or shield etc?

The protective conductor core is one conductor path and the sheath is another. The total size of the conductors including the lives needs to exceed 10mm.

If what is meant by this part is not two individual conductors in the way that I've been saying all along, but what is meant is two paths by virtue of how you connect up individual segments of a single cpc, or what is meant is the presence at any point of two individual segments of a single cpc, how could one cable core and one cable sheath be involved?

Are you meaning as part of a spur? I'd go for one of the conductors into LH E terminal and the other conductor into the RH E terminal of the supply socket, similar for the spur socket.

Yep, I was meaning the wording used in the OSG p60 is along the lines of duplicate protective conductors for compliance with 607-02-04.

1) 607-02-04 is from an old version of the regulations

2) Apart from references to other regulations, 607-02-04 is worded the same as 543.7.1.3.

I never denied the OSG is the 16th edition one, in the absence of the 17th edition OSG the 16th edition vs 607-02-04 is the nearest thing. I have a sneaking suspicion that nothing along these lines will have changed when the 17th ed OSG is released.

 

[Spark123]

folks, wheny ou have finished this highly quoted debate, can someone please summise it in simple statements so that us plain ol DIY'r get to know whatthe outcome is & actually means?

Have a look at page 1, it shows a diagram from an NICEIC publication. The CPC is in the form of a ring. The IET guidance notes also use the same diagram as does the OSG (16th ed). They say it complies with the IEE wiring regulations as it provides duplication of the protective conductor. I'm of the same opinion having read the guidance documents, only trying to explain to Ban how a single ring protective conductor can comply with the regs in respect to this is another challenge!

Ban says it doesn't comply with the IEE regs as there are not two individual protective conductors as in two completely separate ring protective conductors.

Is this a fair summary Ban?

 

[ban-all-sheds]

if you don't have conductors you don't have paths for current to flow.

I know that.

Will you please quote the part of the regulations which talks about protective paths.

It doesn't

So why do you keep on saying that having 2 paths satisfies the regulations?

Which part of 543.7.1.3 does 543.7.2.1 (ii)a comply with?

That depends on the size of the protective conductor.

When you form a radial complying with 543.7.2.1 (ii)a into a ring does it provide two individual protective conductor paths so it complies with 543.7.1.3 (iii)?

543.7.2.3 (iii) does not specify "two individual protective conductor paths" it says you must have two individual protective conductors.

And a single ring protective conductor is not two individual protective conductors.

Now will you please answer the question about the inconsistency that arises when you state that the diagram can show either one single protective conductor (or path) or two individual protective conductors (or paths).

The protective conductor core is one conductor path and the sheath is another.

So each individual conductor - the core and the sheath provide one path?

More inconsistencies in your counting and designation, I'm afraid.

Could you also please explain why, if 543.7.1.3 (iii) means two protective current paths along a single ring cpc, they would even consider writing that second paragraph, as it would be nonsensical to say what it does if they hadn't called for two separate conductors.

If, OTOH, you accept that "two individual protective conductors" means exactly what it says then it makes perfect sense to cover the situation where these might be cores in a multicore cable, or where one is a core and one is a sheath or braid etc.

And oh look - when you do that yet another inconsistency created by your definitions just vanishes.

Are you meaning as part of a spur?

No.

I have a sneaking suspicion that nothing along these lines will have changed when the 17th ed OSG is released.

So if it doesn't, and still contradicts the regulations, what do we do about the fact that BS 7671:2008, ISBN 978-0863418440, is an official ratified national standard and cannot be changed by a non-BS publication put out by someone else?

 

[ban-all-sheds]

Have a look at page 1, it shows a diagram from an NICEIC publication.

Can you please explain what official role NICEIC has in the writing of the wiring regulations or the setting of national standards.

The CPC is in the form of a ring. The IET guidance notes also use the same diagram as does the OSG (16th ed). They say it complies with the IEE wiring regulations as it provides duplication of the protective conductor.

OSG: this guide does not ensure compliance with BS 7671.
GN1: note that this Guidance Note does not ensure compliance with BS 7671.
GN3: note that this Guidance Note does not ensure compliance with BS 7671.

And so on in all the others.

I'm of the same opinion having read the guidance documents, only trying to explain to Ban how a single ring protective conductor can comply with the regs in respect to this is another challenge!

I'm not surprised it's a challenge to explain how a single ring protective conductor can comply with a regulation which calls for "two individual protective conductors, each complying with..." and which then goes on to discuss what happens when these two individual conductors are cores in a multi-core cable, or when one is a core and one is a sheath.

Ban says it doesn't comply with the IEE regs as there are not two individual protective conductors as in two completely separate ring protective conductors.

Is this a fair summary Ban?

Can't disagree with the final sentence...

 

[Spark123]

if you don't have conductors you don't have paths for current to flow.

I know that.

Will you please quote the part of the regulations which talks about protective paths.

It doesn't

So why do you keep on saying that having 2 paths satisfies the regulations?

Which part of 543.7.1.3 does 543.7.2.1 (ii)a comply with?

That depends on the size of the protective conductor.

OK, I'll rephrase that one. Which part of 543.7.1.3 does 543.7.2.1(ii)a comply with when the ring conductor is made up of a 1.5mm conductor?

When you form a radial complying with 543.7.2.1 (ii)a into a ring does it provide two individual protective conductor paths so it complies with 543.7.1.3 (iii)?

543.7.2.3 (iii) does not specify "two individual protective conductor paths" it says you must have two individual protective conductors.

And a single ring protective conductor is not two individual protective conductors.

The guidance would have you believe that as a ring has duplicate protective conductors then it satisfies the requirement for the said reg.

Now will you please answer the question about the inconsistency that arises when you state that the diagram can show either one single protective conductor (or path) or two individual protective conductors (or paths).

A ring has the two paths, as I have drawn and numbered on more than one occasion. Wether it be a ring for a radial or a ring for a ring circuit.

The protective conductor core is one conductor path and the sheath is another.

So each individual conductor - the core and the sheath provide one path?

No, two separate. Unless you are meaning from a perspective of it being downstream on a ring where the current can flow down the sheath and back up the core on its way to the MET? In which case in an open circuit fault on the ring protective conductor there will be one path. In a healthy circuit there will be 2.

Could you also please explain why, if 543.7.1.3 (iii) means two protective current paths along a single ring cpc, they would even consider writing that second paragraph, as it would be nonsensical to say what it does if they hadn't called for two separate conductors.

The regulation does not just cover ring final circuits, it covers radial circuits, spurs etc. As an example it may allow a 2.5mm 3c SWA to be used to supply a radial socket.

 

[ban-all-sheds]

OK, I'll rephrase that one. Which part of 543.7.1.3 does 543.7.2.1(ii)a comply with when the ring conductor is made up of a 1.5mm conductor?

It doesn't.

The guidance would have you believe that as a ring has duplicate protective conductors then it satisfies the requirement for the said reg.

The guidance is not given in BS publications which are able to define or amend formal national standards. And the guidance is in publications which say that they don't ensure compliance with BS 7671.

A ring has the two paths, as I have drawn and numbered on more than one occasion. Wether it be a ring for a radial or a ring for a ring circuit.

Indeed. But if you are going to claim that when the regulations say "protective conductor" they actually mean "protective conductor path", and thus claim that a single ring conductor meets the requirements for two independent conductors, then sticking to your definition of path you have to be able to explain how the diagram with the ring cpc shows both a single protective conductor path and two individual conductor paths, without any inconsistencies.

It would be nice too if you could explain why your definition is so much more reasonable than one based on what the words actually are and which does not introduce any inconsistencies.

So each individual conductor - the core and the sheath provide one path?

No, two separate.

So 4 paths in total then - two conductors each providing two separate paths.

The regulation doesn't ask for 4, it asks for 2.

The regulation does not just cover ring final circuits, it covers radial circuits, spurs etc.

Doesn't matter what it covers. You say that the first paragraph of 543.7.1.3 (iii) doesn't mean two individual cpcs when it uses the term "two individual protective conductors", but then immediately after that the 2nd paragraph starts talking about the situation when these two individual protective conductors clearly are two individual cpcs.

I wonder why that is?

And isn't it interesting that if you take the first paragraph at face value, i.e. that "two individual protective conductors" means just what it says, and what I've been saying all along, then the 2nd paragraph doesn't seem at all strange or out of place.

I wonder why that is?

 

[Spark123]

OK, I'll rephrase that one. Which part of 543.7.1.3 does 543.7.2.1(ii)a comply with when the ring conductor is made up of a 1.5mm conductor?

It doesn't.

So why does 543.7.2.1(ii)a mention a ring? A bit of an inconsistency.

The guidance would have you believe that as a ring has duplicate protective conductors then it satisfies the requirement for the said reg.

The guidance is not given in BS publications which are able to define or amend formal national standards. And the guidance is in publications which say that they don't ensure compliance with BS 7671.

Well, that is the difference between you and me. If I am uncertain about a regulation and how it should be interpreted I will look them up in the guidance documentation issued by a body who should know how to interpret them, in this case it is the same body who issues the IEE regs.

A ring has the two paths, as I have drawn and numbered on more than one occasion. Wether it be a ring for a radial or a ring for a ring circuit.

Indeed. But if you are going to claim that when the regulations say "protective conductor" they actually mean "protective conductor path", and thus claim that a single ring conductor meets the requirements for two independent conductors, then sticking to your definition of path you have to be able to explain how the diagram with the ring cpc shows both a single protective conductor path and two individual conductor paths, without any inconsistencies.

From each point there are two conductor paths. If you disconnect one you still have a path back to the MET via the other so in a healthy circuit there must be two paths. In a healthy state, the protective conductors combine to make up a ring protective conductor.

It would be nice too if you could explain why your definition is so much more reasonable than one based on what the words actually are and which does not introduce any inconsistencies.

The regs require two individual protective conductors. The guidance advises that a ring protective conductor provides a duplication of the protective conductor which meets the requirements.

So each individual conductor - the core and the sheath provide one path?

No, two separate.

So 4 paths in total then - two conductors each providing two separate paths.

I'm completely lost where you are coming from with this one. Are you meaning wiring a ring with a multicore sheathed cable? If so then it isn't required. Are you talking using it for a radial socket from a busbar? In this case it will provide two protective paths.

The regulation does not just cover ring final circuits, it covers radial circuits, spurs etc.

Doesn't matter what it covers. You say that the first paragraph of 543.7.1.3 (iii) doesn't mean two individual cpcs when it uses the term "two individual protective conductors", but then immediately after that the 2nd paragraph starts talking about the situation when these two individual protective conductors clearly are two individual cpcs.

Of course it matters what it covers. That is the whole piont of the regulation. If you look at page 120 of guidance note 8 there is an example of it being used in a radial.

 

[ban-all-sheds]

So why does 543.7.2.1(ii)a mention a ring? A bit of an inconsistency.

Not at all - 543.7.2.1(ii)(a) says you can have a ring, 543.7.1.3 says how big it has to be.

No inconsistency.

I could wire a circuit with singles in conduit which complies with either your version of the requirements for a high integrity cpc or the version written in the regulations, but if I used the wrong sized conductors it would not comply with other regs.

No inconsistency.

Well, that is the difference between you and me. If I am uncertain about a regulation and how it should be interpreted I will look them up in the guidance documentation issued by a body who should know how to interpret them, in this case it is the same body who issues the IEE regs.

Firstly I'm not uncertain - the wording in the regulations is entirely clear.

Secondly why do you choose to believe a non-BS publicaton which explicitly says that it doesn't ensure compliance with BS 7671 and clearly contradicts what the published standard says and creates all manner of inconsitencies which ought to signal to you that its interpretation is at least suspect?

Thirdly, are you really confused, or have you simply taken what the guidance says and tried to make it fit with what the regulations say by inventing requirements not mentioned in the regulations and ignoring the inconsistencies?

From each point there are two conductor paths. If you disconnect one you still have a path back to the MET via the other so in a healthy circuit there must be two paths. In a healthy state, the protective conductors combine to make up a ring protective conductor.

No matter how many times you say that from each point there are two conductor paths the wording of the regulations will not change.

And the wording is "two individual protective conductors, each complying with..", not "two individual conductor paths from each point".

The regs require two individual protective conductors. The guidance advises that a ring protective conductor provides a duplication of the protective conductor which meets the requirements.

The guidance is not given in BS publications which are able to define or amend formal national standards. And the guidance is in publications which say that they don't ensure compliance with BS 7671.

I note though that even if we accept that the presence of two paths is what is meant by the regulations you have still not managed to explain how the diagram with the ring cpc shows both a single protective conductor path and two individual conductor paths, without any inconsistencies.

I'm completely lost where you are coming from with this one. Are you meaning wiring a ring with a multicore sheathed cable? If so then it isn't required.

The regulation doesn't say it's required, that's not relevant to this discussion, and it does you no favours to try and evade answering questions with utterly irrelevant observations like that.

Since you're lost I'll recap the flow of this little bit.

We were looking at the situation covered by the 2nd paragraph of 543.7.1.3 (iii) where the two individual protective conductors required by the first paragraph were either cores in a multicore cable or where one was a core and the other was a sheath or braid etc.

You said "The protective conductor core is one conductor path and the sheath is another."

So I asked you if each individual conductor, i.e. the core and the sheath, provided one path.

And you said "No, two separate".

So if each individual conductor provides two separate paths, and we have two conductors (the core and the sheath) we must have four separate paths, because 2 x 2 = 4.

Of course it matters what it covers. That is the whole piont of the regulation. If you look at page 120 of guidance note 8 there is an example of it being used in a radial.

OK fine - there is an example of it being used in a radial. It doesn't matter where it's used.

You say that the first paragraph of 543.7.1.3 (iii) doesn't mean two individual cpcs when it uses the term "two individual protective conductors", but then immediately after that the 2nd paragraph starts talking about the situation when these two individual protective conductors clearly are two individual cpcs.

As we know full well that 2-core SWA can be used with the cores as phase and neutral and the armour as the cpc there's no way you can say that the cores and the armour are not separate conductors in the same cable. So the 2nd paragraph is talking about a situation where two separate conductors in the same cable are used to meet the requirement of "two individual protective conductors".

Could you please read through both paragraphs again, and without trying to fall back on things like "well what it actually means is two paths" or "well that's not what the guidance says so it must be wrong" will you please explain why the most logical and consistent meaning of "two individual protective conductors" is not the one which is based on what the words actually say?

 

[Spark123]

So why does 543.7.2.1(ii)a mention a ring? A bit of an inconsistency.

Not at all - 543.7.2.1(ii)(a) says you can have a ring, 543.7.1.3 says how big it has to be.

No inconsistency.

I could wire a circuit with singles in conduit which complies with either your version of the requirements for a high integrity cpc or the version written in the regulations, but if I used the wrong sized conductors it would not comply with other regs.

No inconsistency.

If the protective conductor in a radial is wired with a protected 4mm so it complies with 543.7.1.3 (ii) then it complies with 543.7.2.1 (iii) without it being made into a ring, so there is no reason to make it into a ring.
If the conductor is smaller than 4mm then you say it doesn't comply even if you make it into a ring.
So what is the reason for 543.7.2.1 (ii) (a)?
Do you see the inconsistency?

Well, that is the difference between you and me. If I am uncertain about a regulation and how it should be interpreted I will look them up in the guidance documentation issued by a body who should know how to interpret them, in this case it is the same body who issues the IEE regs.

Firstly I'm not uncertain - the wording in the regulations is entirely clear.

You may not be uncertain, but the likes of myself and others who do not read BS publications which are written in a legal type text may not always be 100% certain over the interpretation of a certain regulation and what is deemed to be acceptable ways of going about satisfying them.

Secondly why do you choose to believe a non-BS publicaton which explicitly says that it doesn't ensure compliance with BS 7671 and clearly contradicts what the published standard says and creates all manner of inconsitencies which ought to signal to you that its interpretation is at least suspect?

Why not believe what has been written in a guide issued by the IET about a document written by the IET? If a number of guidance documents issued by the IET all say that a ring protective conductor constitutes a duplicate protective conductor which is deemed to satisfy the requirements then why is that so wrong? Are you wanting us to all get rid of all of our guidance notes, the on site guides etc and just try to use the red book on its own?

Thirdly, are you really confused, or have you simply taken what the guidance says and tried to make it fit with what the regulations say by inventing requirements not mentioned in the regulations and ignoring the inconsistencies?

I'm looking at what the red book says from the point of view of the guidance notes yes, the guidance notes give what is deemed by the IET to be an acceptable method of complying with those regulations they are dealing with.

From each point there are two conductor paths. If you disconnect one you still have a path back to the MET via the other so in a healthy circuit there must be two paths. In a healthy state, the protective conductors combine to make up a ring protective conductor.

No matter how many times you say that from each point there are two conductor paths the wording of the regulations will not change.

And the wording is "two individual protective conductors, each complying with..", not "two individual conductor paths from each point".

Yes, and the IET say in their guidance that they deem a single ring protective conductor to satisfy this requirement.

I note though that even if we accept that the presence of two paths is what is meant by the regulations you have still not managed to explain how the diagram with the ring cpc shows both a single protective conductor path and two individual conductor paths, without any inconsistencies.

There is a single ring protective conductor, call it the CPC if you like. The CPC has two ends, each connected to individual terminals in the MET and provides two protective conductor paths. I'm at a loss as to where you are getting the idea of a single protective conductor idea from.

We were looking at the situation covered by the 2nd paragraph of 543.7.1.3 (iii) where the two individual protective conductors required by the first paragraph were either cores in a multicore cable or where one was a core and the other was a sheath or braid etc.

You said "The protective conductor core is one conductor path and the sheath is another."

So I asked you if each individual conductor, i.e. the core and the sheath, provided one path.

And you said "No, two separate".

So if each individual conductor provides two separate paths, and we have two conductors (the core and the sheath) we must have four separate paths, because 2 x 2 = 4.

Sorry, I thought you were asking if the each conductor provided one path between them. Each conductor will provide a path for current to flow independant of the other i.e. separate. It depends on where an open circuit fault is on the system as to how the protective path is formed.

You say that the first paragraph of 543.7.1.3 (iii) doesn't mean two individual cpcs when it uses the term "two individual protective conductors", but then immediately after that the 2nd paragraph starts talking about the situation when these two individual protective conductors clearly are two individual cpcs.

I don't think they are clearly each a CPC, protective conductors making up a CPC maybe.

As we know full well that 2-core SWA can be used with the cores as phase and neutral and the armour as the cpc there's no way you can say that the cores and the armour are not separate conductors in the same cable. So the 2nd paragraph is talking about a situation where two separate conductors in the same cable are used to meet the requirement of "two individual protective conductors".

I took the 2nd para to mean the likes of using a core inside say a 3c SWA cable and the armour together as two separate protective conductors.

 

[ban-all-sheds]

If the protective conductor in a radial is wired with a protected 4mm so it complies with 543.7.1.3 (ii) then it complies with 543.7.2.1 (iii) without it being made into a ring, so there is no reason to make it into a ring.
If the conductor is smaller than 4mm then you say it doesn't comply even if you make it into a ring.
So what is the reason for 543.7.2.1 (ii) (a)?

543.7.2.1(ii)(a) describes one of the acceptable arrangements, not the only one.

Do you see the inconsistency?

For sockets you can have:

A ring final with a ring cpc complying with 543.7.1.3

OR

A radial final with a ring cpc complying with 543.7.1.3

OR

A radial final with a radial cpc complying with 543.7.1.3 AND a connection from the last socket to the metal conduit or ducting

OR

A radial final with a radial cpc complying with 543.7.1.3 AND a connection from the last socket to the cpc of an adjacent radial final circuit

OR

something else complying with 543.7.1.3

You may not be uncertain, but the likes of myself and others who do not read BS publications which are written in a legal type text may not always be 100% certain over the interpretation of a certain regulation and what is deemed to be acceptable ways of going about satisfying them.

I really really cannot see what is unclear about "two individual protective conductors each complying with the requirements of Section 543".

Confusion arises when you look at what non-BS documents with no power to define or amend published national standards incorrectly say complies with the published national standard and you ignore what the published national standard actually says and start trying to interpret it in a way which fits with what the non-BS documents say.

You can't do that without introducing all sorts of inconsistencies and illogicalities, so when because of that you find that the regulations don't make sense your reaction is "obviously I don't understand what the regulations say, because they don't make sense, therefore I'll not worry about what they say and follow the non-regulatory guidance".

Your reaction should be "it is clear what the regulations say, and it is clear that the guidance does not say the same, therefore the guidance is wrong, as they warn me at the start it might be, and I shall refer to what the regulations actually say".

Why not believe what has been written in a guide issued by the IET about a document written by the IET?

Because the guide does not have the power to define or amend a published British Standard.

If a number of guidance documents issued by the IET all say that a ring protective conductor constitutes a duplicate protective conductor which is deemed to satisfy the requirements then why is that so wrong?

Because that's not what the regulations actually say.

Are you wanting us to all get rid of all of our guidance notes, the on site guides etc and just try to use the red book on its own?

You have to sign a certificate which says that your work complies with BS 761, not one which says it complies with the IET On-Site Guide.

Are you wanting to be telling the truth when you sign it?

I'm looking at what the red book says from the point of view of the guidance notes yes, the guidance notes give what is deemed by the IET to be an acceptable method of complying with those regulations they are dealing with.

But it's not a method deemed acceptable by BS 7671, and the IET document which says it is does not have the power to define or amend a British Standard.

Yes, and the IET say in their guidance that they deem a single ring protective conductor to satisfy this requirement.

But BS 7671 does not say that a single ring protective conductor satisfies that requirement, and the IET guidance does not have the power to amend what BS 7671 says.

There is a single ring protective conductor call it the CPC if you like. The CPC has two ends, each connected to individual terminals in the MET and provides two protective conductor paths. I'm at a loss as to where you are getting the idea of a single ring protective conductor idea from.

I don't think they are clearly each a CPC, protective conductors making up a CPC maybe.

So if you had a circuit wired in cable which had a sheath or braid, but you only used one of the cores as a protective conductor would you not have a cpc? Do you need to use both a core and the sheath to get yourself a cpc?

If you had a circuit wired in 2-core SWA would you not be able to provide a cpc because you only have one protective conductor available?

I took the 2nd para to mean the likes of using a core inside say a 3c SWA cable and the armour together as two separate protective conductors.

That is what it means. 543.7.1.3 (iii) §1 says you've got to have two separate protective conductors. 543.7.1.3 (iii) §2 defines additional requirements of those two separate protective conductors are two separate cores in a multicore cable or where one separate protective conductor is a core and the other separate protective conductor is the sheath/armour/braid.