MSF100 Switch fuses and amended regs

[ban-all-sheds]

Yes there is - BS EN 61439-3.

What does that require re combustibility?

However products to that standard are not considered adequate by BS7671.

Where does it say that?

And if that is the standard which applies but it is not considered adequate then what about

511.1 Every item of equipment shall comply with the relevant requirements of the applicable British Standard, or Harmonized Standard, appropriate to the intended use of the equipment.​

?

I am merely trying to point out that compliance with another country's installation standard would possibly not be sufficient.

But if there is no applicable British or Harmonized standard, then how can any comparison as per this be made?

Alternatively, if equipment complying with a foreign national standard based on an IEC Standard is to be used, the designer or other person responsible for specifying the installation shall verify that any differences between that standard and the corresponding British Standard or Harmonized Standard will not result in a lesser degree of safety than that afforded by compliance with the British Standard. ​

How could someone determine if any differences between a non-existing British or Harmonized standard and a foreign one do or do not result in a lesser degree of safety than that afforded by compliance with a standard which does not exist?

 

[stillp]

What does that require re combustibility?

A glow-wire test or needle flame test in accordance with relevant parts of IEC 60695. Defined and repeatable tests, unlike the requirement in BS7671 for a magic property of 'non-combustibility.

Where does it say that?
?

Amendment 3 states that CUs shall be non-combustible, which is not achieved by conformity to the relevant product standard. (I don't know what "non-combustible" means either, but nonetheless that's what BS7671 seems to demand).

And if that is the standard which applies but it is not considered adequate then what about
511.1 Every item of equipment shall comply with the relevant requirements of the applicable British Standard, or Harmonized Standard, appropriate to the intended use of the equipment.

BS7671 seems to have added a further requirement, that of non-combustibility.

But if there is no applicable British or Harmonized standard, then how can any comparison as per this be made?

Because the additional requirement in BS7671 is not required AFAIK by any British or Harmonised standard, but is additional to relevant British and Harmonised standards. The BSs or ENs do not contain that requirement, therefore conformity to them cannot prove conformity with the requirement in Amdt 3.

 

[JohnW2]

Because the additional requirement in BS7671 is not required AFAIK by any British or Harmonised standard, but is additional to relevant British and Harmonised standards. The BSs or ENs do not contain that requirement, therefore conformity to them cannot prove conformity with the requirement in Amdt 3.

I had to read that at least twice - I presume you're referring to "BSs" other than BS7671?

Kind Regards, John

 

[stillp]

Yes, I had thought that was clear.

 

[JohnW2]

Yes, I had thought that was clear.

Yes, although it's not what you actually wrote, it became fairly clear to me after the second or third read that that was probably what you intended - since it otherwise would make no sense.

Kind Regards, John

 

[ban-all-sheds]

A glow-wire test or needle flame test in accordance with relevant parts of IEC 60695. Defined and repeatable tests, unlike the requirement in BS7671 for a magic property of 'non-combustibility.

Amendment 3 states that CUs shall be non-combustible, which is not achieved by conformity to the relevant product standard. (I don't know what "non-combustible" means either, but nonetheless that's what BS7671 seems to demand).


BS7671 seems to have added a further requirement, that of non-combustibility.

Because the additional requirement in BS7671 is not required AFAIK by any British or Harmonised standard, but is additional to relevant British and Harmonised standards. The BSs or ENs do not contain that requirement, therefore conformity to them cannot prove conformity with the requirement in Amdt 3.

But you can't mix'n'match different bits from different standards to concoct some amalgam of features and call it a "standard"

Either CUs comply with BS EN 61439-3, or they don't. If they comply, then that is what is required by 511.1. If somebody wants to use a CU which complies with another standard, which standard does 511.1 require them to compare that against to determine if it is safe enough?

 

[JohnW2]

Either CUs comply with BS EN 61439-3, or they don't. If they comply, then that is what is required by 511.1.

Not all that is required by 511.1. It also requires demonstration that compliance with that Standard doesn't result in it being 'less safe' than it would be if compliant with BS7671 itself - and since we're not clear as to what is required for compliance with BS7671 (Amd3), we're a bit stuck!

Kind Regards, John

 

[ban-all-sheds]

No - 511.1 requires that if equipment complying with a foreign national standard based on an IEC Standard is to be used then you have to consider any differences between that standard and the corresponding British or Harmonized standard. And the corresponding British or Harmonized standard is BS EN 61439-3.

 

[JohnW2]

No - 511.1 requires that if equipment complying with a foreign national standard based on an IEC Standard is to be used then you have to consider any differences between that standard and the corresponding British or Harmonized standard. And the corresponding British or Harmonized standard is BS EN 61439-3.

Yes, you're right.

However, does not 421.1.101 over-ride that - since, whilst 511.1 is 'generic', 421.1.101 relates specifically to CUs etc. in domestic premises?

Kind Regards, John

 

[ban-all-sheds]

Yes, so if I want to use a CU which complies with IEC{made-up-number}, what do I compare that against to carry out the comparison required by 511.1?

 

[JohnW2]

Yes, so if I want to use a CU which complies with IEC{made-up-number}, what do I compare that against to carry out the comparison required by 511.1?

As I've said, repeatedly, you can't - and won't be able to unless/until 421.1.101 is amended such as to actually explain what it is requiring.

Kind Regards, John

 

[ban-all-sheds]

The ripples of mess from 421.1.101 just keep spreading, don't they.

OTOH - as "non-combustible" is not defined, then I would really like to know what BS EN 61439-3 & IEC 60695 say. Not so much what is required in the way of tests, but whether the property which is to be demonstrated by successfully passing the tests is called "non-combustibility".

 

[stillp]

The ripples of mess from 421.1.101 just keep spreading, don't they.

OTOH - as "non-combustible" is not defined, then I would really like to know what BS EN 61439-3 & IEC 60695 say. Not so much what is required in the way of tests, but whether the property which is to be demonstrated by successfully passing the tests is called "non-combustibility".

No, it isn't called that. It's "Resistance to abnormal heat and fire IIRC, and the criterion for passing the tests is that the materials are self-extinguishing. Far from "non-combustible".

 

[JohnW2]

No, it isn't called that. It's "Resistance to abnormal heat and fire IIRC, and the criterion for passing the tests is that the materials are self-extinguishing. Far from "non-combustible".

If they haven't already, I feel sure that the authors of BS7671 are going to live to regret ever having used that term!

It's now less than 18 months before the BS7671:2018 ("18th ed.") is due to be published. Do you have any idea when the draft for public consultation is likely to appear?

Kind Regards, John

 

[stillp]

I feel sure that the authors of BS7671 are going to live to regret ever having used that term!

I'm sure they already do.

Do you have any idea when the draft for public consultation is likely to appear?

No, I have no 'insider knowledge' of the machinations of the JPEL. If you go to any of the Elex exhibitions you could try asking IET staff there.