Shed straight concentric supply query

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Are you saying, therefore, that ali-tube IS without doubt definitely suitable for burying in the ground?
 
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Are you saying, therefore, that ali-tube IS without doubt definitely suitable for burying in the ground?
Absolutely not. If you recall I objected to what I perceived was an assertion from you and John that it was.

John has now clarified that his use of "seem" etc meant he was uncertain.


But all this "he said/you said/I said/he meant/you meant/I meant" stuff is getting us nowhere, and we should draw a line under it.


My position is, and always has been, that there is so little clarity about what is required, and about what BS 7671 means when it uses a term relating to a cable component if we assume that the one thing it does not mean is what the BS for that cable means when specifying the components of that cable, that any pronouncement on what complies BS 7671 cannot be made with any degree of certainty.

And all that the pages of back and forth have done is to show that I am right about that.

Clarification from the authors of BS 7671 could resolve it, either in the form of a definition, or a specific approval of particular cable type(s) but until then I really don't see how the uncertainty can be resolved by cherry-picking non-technical definitions and a subset of manufacturer usages.

It could be that when resolved it turns out that you may indeed directly bury that cable, or it may not.

John and I are uncertain. I don't know what reasoning he went through, but my uncertainty is based on the following, all of which are indisputable facts:
  • BS 7671 does not define what it means by "metal sheath".
  • BS 8436 does not require anything which it calls a "metal sheath".
  • The cable component which BS 8436 does call a "sheath" is not metal.
  • The title of BS 8436 says it is for cables for use in walls, partitions and building voids, no other use is mentioned.
 
No, I'm arguing that a cable that has something which meets the dictionary definition of "a sheath", and where that "sheath" is metallic, has something which is a "metallic sheath" regardless of what the manufacturer or standards call it.
You may not take a term defined by a standard, give it a different meaning, and then claim that the standard says that the {whatever} has that thing.
Still going with your "read something not written and criticise it" approach. I did not mention BS8436. I referred to the manufacturers description of their cable which you specifically quoted.

So are you arguing that aluminium is not metallic ?
Are you arguing that a "tube" enclosing the cores does not meet the definition of "sheath" ?
I'm arguing that the definition of the construction of a cable to BS 8436 does not give it a metal sheath.
So dodging the question again. Does the description given by the manufacturer of their cable say it has an aluminium tube surrounding the cores or doesn't it ? What BS whatever says is irrelevant since 522.8.10 doesn't say "... metallic sheath complying with BS whatever".
So simple questions again - are you arguing that the manufacturer does not say in the spec you quoted that it has an aluminium tube surrounding the cores ? Are you arguing that aluminium isn't metallic ? Are you arguing that such a tube surrounding the cores does not meet the definitions already given of "sheath" ?

It also has an XLPE sheath over the top of that, but that doesn't alter the nature of the sheath inside it.
There is no sheath inside it.
See above. The manufacturer states that there is an aluminium tube surrounding the cores - according to the dictionary definitions (for which you have proposed no counter definition) then that can be described as a sheath. The fact that there is then another (XLPE) sheath over the top of that does not change that.


I'll add you to the list of people whose only concern seems to be to argue themselves out of accepting that there is clearly insufficient clarity about the term for any claim that there is to be valid.
I agree that there is a slight lack of clarity, but what you are arguing goes completely against any reasonable interpretation of what is written. In part you appear to be relying on a definition of "sheath" meaning only the outermost covering - ie that there cannot be more than one layer which could be considered a "sheath" according to definitions which you have not disagreed with (let alone come up with any counter definition).
My only argument is against people (well just you as it happens) who refuse to read what is written and bring in arbitrary diversions (eg BS8436) which are not invoked by 522.8.10 in BS7671 to try and prove that "black is white".

So I again ask :
Are you arguing that the manufacturer does not say in the spec you quoted that it has an aluminium tube surrounding the cores ? Are you arguing that aluminium isn't metallic ? Are you arguing that such a tube surrounding the cores does not meet the definitions already given of "sheath" ?
And look forward to you wriggling and avoiding answering them - yet again.
 
Returning to tidy up, and remove my contributions to the pointless back-and-forth started by Simon.
  • The standard for BS 8436 cables does not require it to have a metal sheath.
  • The metal layer it has is not called a sheath.
  • What it does call a sheath is not made of metal.
  • A maker of a BS 8436 cable does not call the metal layer a sheath.
  • What the maker of the cable calls a sheath is not made of metal.
  • BS 7671 does not define the term "metal sheath".
  • It is lacking in credibility to ignore all of that, and declare that the cable must have a metal sheath, and that it must be what BS 7671 requires, and therefore it must be compliant with 522.8.10 for direct burial, and there cannot possibly be enough doubt about that to be concerned and we must not even entertain the possibility that there might be a technical definition which applies.
 
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Continued reference to the manufacturer's description is diverting the argument from the salient points.

The point is that 522.6.204 specifically states that this BS8436 cable is suitable for burying in walls outside of the 'safe' zones without RCD coverage.

It therefore follows that for the purposes of 522.6.204 the metallic screen is considered compliant as an earthed metallic covering which complies with the requirements of these regulations for a protective conductor.
Therefore the screen is a compliant covering.

By standard English definition a sheath is a covering so how can the cable not be suitable for and compliant with 522.8.10?



The only compelling argument against that must be that "a sheath is not a covering".
 
The only compelling argument against that must be that "a sheath is not a covering".
Quite so - and, as you have demonstrated, at least one standard English (dictionary) definition says that a sheath is a covering of an electric cable.

Kind Regards, John
 
But we can do that if you want.
Their description is of a BS 8436 cable, and it fits with the terms in that.
And BS8436 is relevant in what way ?
So, if you prefer
  • The maker's description does not contain the term "metal sheath".
  • The cable component which is a metal layer is not described by them as a "sheath".
  • The cable component they do call a "sheath" is not metal.
Again, deliberately dodging the question.
Do they say that it has an aluminium tube surrounding the cores ? You have avoided answering that.
Is aluminium metallic ? You've avoided answering that.
Does a "tube" meet with the only definitions we have at the moment for "a sheath" ? You have avoided answering that as well.

And I answered that I'm arguing that the definition of the construction of a cable to BS 8436 does not give it a metal sheath.
Again, in what way is BS8436 relevant ?

The question is not "does the cable meet the design laid down in BS something ?", the question is "does the cable have a metallic sheath ?" which is the only question relevant to 522.8.10.

It really doesn't matter how often you repeat your "when did you stop beating your wife" type of question, you're only going to get the same answer.
And yet again, another attempt to distract from the question since this is no way a "when did you stop beating your wife" type question.

Aluminium is either metallic or it's not. A "tube" is either "a" sheath or it is not. The cable either has such a tube or it does not.

It appears to me that this is your position:
  • You can see that the standard for BS 8436 cables does not require it to have a metal sheath.
  • You can see that the metal layer it has is not called a sheath.
  • You can see that what it does call a sheath is not made of metal.
  • You can see that the maker of a BS 8436 cable does not call the metal layer a sheath.
  • You can see that what the maker of the cable calls a sheath is not made of metal.
  • You think that you can ignore all of that, and declare that the cable must have a metal sheath, and that it must be what BS 7671 requires, and therefore it must be compliant with 522.8.10 for direct burial, and there cannot possibly be enough doubt about that to be concerned and we must not even entertain the possibility that there might be a technical definition which applies.
Then you have misinterpreted my position. I have not referenced BS8436 (other than to ask you why you think it's relevant when it is not mentioned in 522.8.10) and so anything it says is not relevant to the question. I also have not said that the maker calls the aluminium tube a sheath - but what I have said is that it meets the definition of a sheath.
So basically I am not ignoring the 5 irrelevant things you accuse me of ignoring because they are not in the least bit relevant to the discussion. However, if you take out the "You think that you can ignore all of that" then that last statement is correct. The cable whose description you quoted DOES have a metallic sheath (aluminium is metallic, the aluminium layer is a tube, a tube meets the definition of sheath) and therefore for the purposes of 522.8.10 it is permitted to be direct buried IF the aluminium layer meets the requirements for a CPC for the circuit (so requires knowing the effective CSA of the aluminium layer, adequately terminating that layer, and working out what capcity of circuit the CPC is therefore suitable for).
So which of those basic statements do you state as incorrect ? Is it that aluminium is metallic ? Is it that the aluminium layer is stated by the manufacturer to be a tube ? Is it that a tube surrounding the cores meets the definition of a sheath ?
Whether other aspects of the cable make it suitable or unsuitable for direct burial is not relevant to 522.8.10. But given that the outer sheath (not "the" sheath, the outer sheath) is XLPE then it's hard to see how it would not be.
Far from arguing that black is white, I'm arguing that things are so grey that nobody who declares that without doubt they can see either black or white can be justified.
Actually it is very black and white in this case. So far your objection seems to be that "the manufacturer calls the layer something different" and "some random BS not mentioned in 522.8.10 uses different terms".

Continued reference to the manufacturer's description is diverting the argument from the salient points.
I'm not sure it is. The cable BAS quoted a description of was very clear that the cable included a complete metallic sheath regardless of whether BS8436 specifies a foil layer or braid or what it calls it.
The only compelling argument against that must be that "a sheath is not a covering".
That, and "someone else calls it something else" - as if someone calling it a "stripey horse" somehow stops a zebra being a zebra.
 
Continued reference to the manufacturer's description is diverting the argument from the salient points.
Not at all, when they too do not describe the cable as having a metal sheath.


The point is that 522.6.204 specifically states that this BS8436 cable is suitable for burying in walls outside of the 'safe' zones without RCD coverage.

It therefore follows that for the purposes of 522.6.204 the metallic screen is considered compliant as an earthed metallic covering which complies with the requirements of these regulations for a protective conductor.
Therefore the screen is a compliant covering.

By standard English definition a sheath is a covering so how can the cable not be suitable for and compliant with 522.8.10?
522.8.10 calls for a metal sheath.

BS 8436 cables do not have a metal sheath. It matters not a jot what standard English, or non-technical definitions say - in the context of electrical regulations and official standards for cables they do not have a metal sheath.

You are all basing your arguments on the idea that no matter what BS 7671 might mean by "metal sheath", the one thing it cannot possibly mean is what the BS standard for the cable in question means.

I believe that that is a very dubious idea.
 
It does not meet the definition of the sheath in BS 8436.
Which is not the question I asked.
Whether it meets the definition in BS 7671 522.8.10 nobody, not you, not I, not EFLI knows.
Actually we do - because the description of the cable is clear. Regardless of what BS something may require of the cable construction, if the cable has a completely enclosing aluminium tube then it has a metallic sheath according to any reasonable definition of sheath.
... to see that the lack of a proper definition can do nothing but create uncertainty.
Indeed, and then we must fall back to accepted english language usage and dictionaries which document that usage.
A cable to BS 8436 does not have a metal sheath. It really doesn't.
Rubbish. A cable to BS something may not be REQUIRED to have a sheath to meet that standard, but unless the standard explicitly prohibits having a structure which could be described as a metallic sheath according to the definitions we have available, then you cannot say that "cables to BS something do not have blah".
Does BS whatever have anything which prohibits having a continuous metallic tube around the cores ? I think not since some cables made to meet it's requirements do have that.
A cable to BS 8436 does not have such a sheath. It really does not. If it does, show where the name of the standard, or the entries in the table of contents, or the diagrams identifying the parts, or the descriptions of the makers say that it does.
I've already shown you the logic behind that. You have so far failed to come up with ANY valid counter argument.
So, if you have a definition of "sheath" which is not more or less the same as what's been cited before - " covering on a cable" - then cite it. Otherwise just accept that a covering on a cable is a sheath, a continuous tube around the cores is therefore a covering and therefore a sheath, and if that tube is aluminium then the cable DOES have a metallic sheath.

If you have a definition that disagrees with that then cite it.
Please show where the name of the standard, or the entries in the table of contents, or the diagrams identifying the parts, or the descriptions of the makers say that it does.
I have not claimed that it does, never. I am simply observing that the manufacturers description is clearly of a cable which does have a metallic sheath - unless you can come up with a definition of sheath that does not include an aluminium tube around the cores.
Not necessarily, because it is not clear what 522.8.10 means by "metal sheath".
Actually it's quite clear. We know what "metal" means, we know what "sheath" means, so we know that it simply means a cable with a sheath which is made of metal - you're not very good at this english language stuff are you !
It does not meet the definition of the sheath of a BS 8436 cable. That is a matter of fact easily verified by looking at the information on the BSI website.
If I wanted to spend a ridiculous amount buying a standard I have no need of. And besides, as I've already explained, my statements of fact do not rely on the working of that BS - which you clearly understand since you've put so much effort into steering the discussion away from demonstrating that you are wrong.
It really does not matter how many more times you go around and around this loop, asking the same questions, the following will always be true:
  • You can see that the standard for BS 8436 cables does not require it to have a metal sheath.
  • You can see that the metal layer it has is not called a sheath.
  • You can see that what it does call a sheath is not made of metal.
  • You can see that the maker of a BS 8436 cable does not call the metal layer a sheath.
  • You can see that what the maker of that cable calls a sheath is not made of metal.
And again, while those 5 statements are true, they do not IN ANY WAY prove your point.
And denying that you are ignoring those
I have not ignored those - they do not prove what you claim
when you assert that the cable must have a metal sheath
You accept that it has a metallic tube surrounding the cores, so we are down to what that metallic tube may be called. I don't really care what OTHER names it may be called, it meets the definition of "sheath" and therefore it IS a sheath. If you contend that, then please cite your official definition of sheath which does not encompass a "metal tube surrounding the cores"
, and that it must be what BS 7671 requires
Well BS 7671 requires a metallic sheath, the cable you cited a description of has a metallic sheath - the only doubt is that you refuse to accept that a metallic sheath meets the requirements for a metallic sheath.
, and therefore it must be compliant with 522.8.10 for direct burial
So 522.8.10 requires a metallic sheath, the cable has a metallic sheath - where's the doubt about that (assuming we've covered the suitability by way of effective CSA as a CPC) ?
, and there cannot possibly be enough doubt about that to be concerned and we must not even entertain the possibility that there might be a technical definition which applies is just as lacking in credibility as the assertion itself.
Please cite this mythical definition you keep relying on ? I've given citations for the definition I'm relying on, unless you have a differing defintion then you have no argument and are just being your usual belligerent self refusing to accept that you might not be right.
Give it up - it is going nowhere except a thread lock. If that's what you want, then keep it up, and I will keep on giving you the same answers to your same questions.
The same WRONG answers, the same misdirections, the same bigotry.


Tell you what, lets condense this down to just ONE question ? Do you have a definition of "sheath" which differs from those already cited ? Yes or No ? If Yes, citation please.
 
So that would be an admission that you do not have a different definition of "sheath" then ? In which case your argument goes out the window. Case closed.
 
I think the numptys have declared that swa cable should not be buried below ground. We're all doomed.
 
I think the numptys have declared that swa cable should not be buried below ground. We're all doomed.
It's hard to tell amongst all the noise (particularly since I can't be bothered to read it all!), but I think that even they have conceded that the regs allow cable with earthed armour, as well as cable with an earthed 'sheath', to be buried underground!

Kind Regards, John
 
"Conceded"?

Do I have to show you what the actual definition of that word is in order to prove that it's an idiotic one to use, or do you already know that?

Has there been any discussion here about whether armoured cable may or may not be buried?

Have there been any assertions made that it may not, or that it might not be suitable?

Has anybody who made such an assertion later admitted that they were wrong?

"Conceded"? What on earth is wrong with you? What are you trying to do?


Interesting to note, though, that Simon understands as little about the discussion as watson does.
 

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