Another BS 5733 "not quite"?

ban-all-sheds · 29 Nov 2017

https://www.quickwire.co.uk/product/quickwire-switch-load-junction-box/

They say "BS 5733-MF", but I see no MF mark on the enclosure.

I wonder if it is BS 5733 which requires that, or if it's a BS 7671 speciality? Can't help wondering if it is the latter - if it were in BS 5733 why would it be explicitly required in 526.3?

Looks like a neat idea - I like the way you just push T&E in. I don't like the price as much.

JohnW2 · 29 Nov 2017

ban-all-sheds said:
They say "BS 5733-MF", but I see no MF mark on the enclosure. I wonder if it is BS 5733 which requires that, or if it's a BS 7671 speciality? Can't help wondering if it is the latter ....

I would also be very much inclined to suspect the latter, and I'm not really sure that BS 7671 can really 'do it', either ....

... British Standards define what is required of a product or piece of work in order for it to conform with the Standard and I'm not at all sure that whether or not a product bears some certain marking can affect whether or not it conforms.

As I understand it, legislation can require various types of conformity marking, but that's obviously a different matter.

We need stillp again!

Kind Regards, John

mfarrow · 29 Nov 2017

JohnW2 said:
I would also be very much inclined to suspect the latter, and I'm not really sure that BS 7671 can really 'do it', either ....

It's the former. 5733 defines the symbol and the definition for maintenance free: "accessory which does not require further inspection, testing or maintenance after installation in a circuit, and which incorporates screwless terminals (see 14.5) and cable clamps to secure any associated cables".

There's a list of tests for screwless terminals and separately "terminals for maintenance free accessories" which further include thermal cycling and 1512hr testing at rated current to check for volt drop.

JohnW2 · 29 Nov 2017

mfarrow said:
It's the former. 5733 defines the symbol and the definition for maintenance free: "accessory which does not require further inspection, testing or maintenance after installation in a circuit, and which incorporates screwless terminals (see 14.5) and cable clamps to secure any associated cables". ... There's a list of tests for screwless terminals and separately "terminals for maintenance free accessories" ...

I think we had all assumed that much, although none of us appear to know of any of the details.

However, the question is whether BS 5733 itself does (or, indeed, could) impose a 'requirement' for a product conforming to the Standard to bear the symbol it defines.

As I wrote last night, I would have doubted that a product which had passed all the tests etc. required by 5733 would be regarded as "not conforming to BS 5733" if it did not bear the symbol - and, more generally, I also expressed my uncertainty as to whether a Standard (as opposed to legislation or regulations) can impose such a 'requirement'.

Can you clarify any of these issues?

KInd Regards, John

ban-all-sheds · 29 Nov 2017

JohnW2 said:
I would also be very much inclined to suspect the latter, and I'm not really sure that BS 7671 can really 'do it', either ....

It does it with "non-combustible" CUs. That's a BS 7671-only requirement layered on top of the BS EN 6xxxxx standard that applies to CUs.

ban-all-sheds · 29 Nov 2017

mfarrow said:
It's the former. 5733 defines the symbol and the definition for maintenance free:

So

526.3(vi) Equipment complying with BS5733 for a maintenance free accessory and marked with the symbol MF and installed in accordance with the manufacturers instructions.

is a tautology?

ban-all-sheds · 29 Nov 2017

http://electrical.theiet.org/wiring-matters/42/junction-boxes.cfm?type=pdf

JohnW2 · 29 Nov 2017

ban-all-sheds said:
It does it with "non-combustible" CUs. That's a BS 7671-only requirement layered on top of the BS EN 6xxxxx standard that applies to CUs.

Yes, but I think that's a bit different.

I see no problem with one Standard saying that, in order to conform to it, one has to satisfy the requirements of some other Standard "plus XYZ". That can avoid a lot of duplication.

What I am less certain about is whether any Standard can can that something which passes all the required tests would nevertheless be regarded as "not conforming" simply because it did not bear some symbol. If such a matter ever came to Court, I would imagine that the Court would be satisfied with demonstration that it had passed all the tests etc., regardless of any markings or the lack of them.

Kind Regards, John

ban-all-sheds · 29 Nov 2017

JohnW2 said:
Yes, but I think that's a bit different.

No - it might be exactly the same.

I see no problem with one Standard saying that, in order to conform to it, one has to satisfy the requirements of some other Standard "plus XYZ".

That might be exactly what is going on here.

What I am less certain about is whether any Standard can can that something which passes all the required tests would nevertheless be regarded as "not conforming" simply because it did not bear some symbol. If such a matter ever came to Court, I would imagine that the Court would be satisfied with demonstration that it had passed all the tests etc., regardless of any markings or the lack of them.

Surely that principle doesn't clash with our supposition that the symbol is required by BS 7671, not BS 5733?

I said:
I wonder if it is BS 5733 which requires that, or if it's a BS 7671 speciality? Can't help wondering if it is the latter - if it were in BS 5733 why would it be explicitly required in 526.3?

And in agreement you said:
I would also be very much inclined to suspect the latter

I'm not saying that I think BS 5733 requires the symbol in order for a product to be in compliance, I'm saying I think that BS 7671 is adding that requirement, as in

526.3(vi) Equipment complying with BS5733 for a maintenance free accessory and marked with the symbol MF ....

I thought you were in agreement.

421.1.201 Within domestic (household) premises, consumer units and similar switchgear assemblies shall comply with BS EN 61439-3 and shall:
i. have their enclosure manufactured from non-combustible material, or...

does not mean that having an enclosure manufactured from non-combustible material is a requirement of BS EN 61439-3, it means that BS 7671 requires a product which complies with BS EN 61439-3 and has an additional feature.

526.3(vi) Equipment complying with BS5733 for a maintenance free accessory and marked with the symbol MF .... does not mean that BS 5733 requires maintenance free accessories to be marked with the symbol MF, it means that BS 7671 requires a product which complies with BS 5733 and has an additional feature.

JohnW2 · 29 Nov 2017

ban-all-sheds said:
Surely that principle doesn't clash with our supposition that the symbol is required by BS 7671, not BS 5733? .... I thought you were in agreement.

Well, we know that it is 'required' by BS7671, and think that it may not be required by BS 5733, so we are definitely in agreement about that.

What I'm questioning is whether any Standard (BS 7671 or otherwise) relating to the required performance of a product (i.e. passing specified tests) can say that a product does not conform to the Standard if it passes all the tests etc. but does not have some marking on it.

As I've said, it's fair enough for legislation/regulations to 'require' that a product conforming to a particular Standard should bear a marking indicating that conformation, but I am far less sure that it is possible (or appropriate) for a Standard to say that a product which otherwise would conform does not conform because it doesn't have a particular marking.

This is really a generic question about Standards, so we really do need stillp (or my father, but he died nearly 50 years ago!).

Kind Regards, John

mfarrow · 29 Nov 2017

There is a section called "Information to be marked on accessories". It mandates ("shall") the name/TM of manufacturer/vendor and "BS 5733".

It then says "other information shall be marked if relevant: ... k) for accessories classified according to 4i) as maintenance free, the appropriate symbol specified in 8.4." The appropriate symbol being the (MF) logo of course.

Therefore I read it as the marking is a requirement in the standard if the product complies the requirements of the testing.

JohnW2 · 29 Nov 2017

mfarrow said:
There is a section called "Information to be marked on accessories". It mandates ("shall") the name/TM of manufacturer/vendor and "BS 5733".

Interesting. A Standard can, of course, not 'mandate' anything. I suppose it could say that a product would not be regarded as conforming to the Standard if, despite having passed all the required tests, it did not bear the marking - but that would seem rather odd to me, since it's not really within the spirit of a Standard.

More generally, as far as I am aware, there are any number of products for which there are 'relevant Standards' for which even products which do conform to the Standard do not necessarily bear any marking to that effect.

In terms of electrical things, as I have implied, I believe that there is legislation which requires some items to conform to particular Standard(s) and also that the products must be marked to confirm that conformation - but that is very different and, as far as I am aware, is not the case with MF junction boxes/connectors. I imagine there are similar legislated requirements for marking in other fields.

Kind Regards, John

ban-all-sheds · 29 Nov 2017

JohnW2 said:
What I'm questioning is whether any Standard (BS 7671 or otherwise) relating to the required performance of a product (i.e. passing specified tests) can say that a product does not conform to the Standard if it passes all the tests etc. but does not have some marking on it.

FGS.

BS 7671 is NOT saying that an MF accessory does not conform with BS 5733 unless it has some sort of marking. It is saying that to conform with BS 7671 the accessory must conform with BS 5733 AND have some sort of marking.

Just like it does NOT say that a "combustible" CU does not conform with BS EN 61439-3, it says that to conform with BS 7671 the CU must conform with BS EN 61439-3 AND be "non-combustible".

I could extend/modify an old installation using harmonised cable, and I could use materials which fully conform with all of their appropriate standards, not one of which involves sticking a label on to warn of mixed colours, but to conform with BS 7671 I do have to apply such a notice.

I really do not understand why you struggle so with the concept that BS 7671 can require A + B without that creating a requirement that A also requires B.

As I've said, it's fair enough for legislation/regulations to 'require' that a product conforming to a particular Standard should bear a marking indicating that conformation,

Well unless you want to claim that 526.3(vi) contains a tautology, that is exactly, and only, what BS 7671 is doing.

but I am far less sure that it is possible (or appropriate) for a Standard to say that a product which otherwise would conform does not conform because it doesn't have a particular marking.

Well unless you want to claim that 526.3(vi) contains a tautology, BS 7671 is recognising the situation that an otherwise BS 5733 conformant product does not have to have a particular marking to conform with BS 5733.

JohnW2 · 29 Nov 2017

ban-all-sheds said:
BS 7671 is NOT saying that an MF accessory does not conform with BS 5733 unless it has some sort of marking.

Indeed not.

ban-all-sheds said:
It is saying that to conform with BS 7671 the accessory must conform with BS 5733 AND have some sort of marking.

Indeed it is - and, in turn, I am saying that I am far from sure that is the place of a BS to 'require' that, in order to conform with itself, a product which conforms to some other technical Standard has to be marked in some particular way to indicate its conformation with that other Standard.

I may, of course, be wrong. As I said, we need stillp.

Kind Regards, John

ban-all-sheds · 29 Nov 2017

JohnW2 said:
Interesting. A Standard can, of course, not 'mandate' anything. I suppose it could say that a product would not be regarded as conforming to the Standard if, despite having passed all the required tests, it did not bear the marking - but that would seem rather odd to me, since it's not really within the spirit of a Standard.

With the disclaimer that I do not have the current versions, and they may therefore have been removed,

this is from BS 1363:1984 Incorporating Amendment Nos. 1, 2, 3, 4, 5 and 6:

This is from BS 1362:1973 Incorporating Amendment Nos. 1 and 2:

And this is from BS 1361:1971 Incorporating amendments issued January 1983 (AMD 4171), January 1985 (AMD 4795) and January 1991 (AMD 6692)

So standards can, and do, require markings as part of conformance requirements.

mfarrow says that BS 5733 does, which means that:

a) 526.3(vi) contains a tautology.

b) That Quickwire product does not appear to conform, although given how we've been misled by photos of products with almost invisible markings it would not be right to say for sure that it doesn't without confirmation from the maker about where the mark is.

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Another BS 5733 "not quite"?

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