Mixed brand MCBs and EICR coding

[stillp]

If a Chinese manufacturer produced a copy of an accepted/approved/'safe' product and were able to satisfy a reputable regulatory authority that their copy was, in all respects, 'identical' (to within whatever tolerance the authority required) to the established product, would you still have concerns about that product?

That would depend on the competence and rigour that was applied by the regulatory authority. Would that extend to, for example, examination of the production controls and supplier criteria?

Well, I wouldn't for other reasons but as far as the speed rating is concerned it would be acceptable.

Yes, but cornering might well be compromised.

 

[stillp]

Does "facts pointing to a risk" means that a realisation of that risk has been demonstrated (products failing to perform satisfactory, or being harmed), or merely that there are facts which form a theoretical basis for speculation about a possible risk?

I think you are confusing "risk" with something else. If analysis, theory, observation, or whatever shows that something can lead to the potential to cause harm, then there is a risk, whether that risk has ever been realised or not.

 

[EFLImpudence]

So, they are all the same, then.

What are? The devices are certainly not. The tests are.

If a component - e.g. MCB - is subject to the same tests, to qualify as type tested, as another similar component, then surely they can be classed as the same in all relevant respects.

 

[JohnW2]

Which regulation?

I was talking about regulation 530.3.4 of BS7671. Although we may have somewhat lost focus, this thread is are about EICRs and the OP asked what regulation of BS7671 (if any) should be cited if 'coding' mixed-make devices on an EICR.

Components cannot conform to 61439, since it is not a component standard.

In that case, you had better to explain that to your colleagues/contacts on JPEL/64, since they wrote that a domestic CU must "... incorporate components and protective devices specified by the manufacturer complying with BS EN 61439-3" ... unless, that is, you can think of some other interpretation of that statement.

Kind Regards, John

 

[stillp]

So, they are all the same, then.

What are? The devices are certainly not. The tests are.

If a component - e.g. MCB - is subject to the same tests, to qualify as type tested, as another similar component, then surely they can be classed as the same in all relevant respects.

No! Why on earth should that be? They have to pass certain performance tests, and some tests on materials. That does not mean they are the same, although (taken as components) they might perform the same function, with the same degree of assurance.
Most cars have to pass the same type test. Does that mean they are all the same, or that their parts are interchangeable?

 

[stillp]

since they wrote that a domestic CU must "... incorporate components and protective devices specified by the manufacturer complying with BS EN 61439-3"

That reference to 61439 refers to the CU, not the components. Perhaps they should have added a comma after "consumer unit", and after "manufacturer".

 

[EFLImpudence]

Well, I wouldn't for other reasons but as far as the speed rating is concerned it would be acceptable.

Yes, but cornering might well be compromised.

Ah, good point.

That is a case of not wanting a better product alongside a lesser even though they have both met the required test.
What is the MCB equivalent?

 

[JohnW2]

I was responding to stillp's comment (which I continue to find hard to believe) that it is "quite likely" that a protective device will fail if housed in the 'wrong' enclosure

I CBA to check back, but if I referred to a wrong enclosure, I was mistaken.

I've checked for you. You wrote...

.... It's quite likely that they will pass the tests in one manufacturer's enclosure and not in another.

... which is what I regarded as rather disturbing.

The issue is not one of putting devices into the wrong enclosure, but is one of mixing components within an enclosure in a way which has not been type-tested. The enclosure is of course one of those components.

Fair enough, but are you still saying that it is "quite likely" that devices will fail the tests if they are in a 'mixed components' situation? If so, what do you mean by "quite likely"? I would have thought that, in normal usage, that phrase would imply a probability of at least, say, 1 in 10, probably much higher.

Kind Regards, John

 

[EFLImpudence]

If a component - e.g. MCB - is subject to the same tests, to qualify as type tested, as another similar component, then surely they can be classed as the same in all relevant respects.

No! Why on earth should that be? They have to pass certain performance tests, and some tests on materials. That does not mean they are the same, although (taken as components) they might perform the same function, with the same degree of assurance.
Most cars have to pass the same type test. Does that mean they are all the same, or that their parts are interchangeable?

If the part is the same size (physically fits) and has passed the same required tests, for example a brake pad, then yes.

 

[JohnW2]

I think you are confusing "risk" with something else. If analysis, theory, observation, or whatever shows that something can lead to the potential to cause harm, then there is a risk, whether that risk has ever been realised or not.

With respect, I think it is you that is confusing "risk" with something else (namely "hazard"). To quote again from the HSE ...
"‘A Hazard is a potential source of harm or adverse health effect on a person or persons’."
and ..
" Risk is the likelihood that a person may be harmed or suffers adverse health effects if exposed to a hazard."

.. from which it should be clear that you are talking about hazards (potential sources of harm) and that risk is a quantification of the probability of the hazard resulting in harm, which cannot be evaluated if consequences of the hazard have never been realised.

Kind Regards, John

 

[JohnW2]

If a Chinese manufacturer produced a copy of an accepted/approved/'safe' product and were able to satisfy a reputable regulatory authority that their copy was, in all respects, 'identical' (to within whatever tolerance the authority required) to the established product, would you still have concerns about that product?

That would depend on the competence and rigour that was applied by the regulatory authority. Would that extend to, for example, examination of the production controls and supplier criteria?

Very much so, in the case of medicinal products. Even changes in key personal at the manufacturing facility, and certainly any changes in the supply chain of raw ingredients, will usually trigger a re-assessment/review of the product approval.

Kind Regards, John

 

[JohnW2]

since they wrote that a domestic CU must "... incorporate components and protective devices specified by the manufacturer complying with BS EN 61439-3"

That reference to 61439 refers to the CU, not the components. Perhaps they should have added a comma after "consumer unit", and after "manufacturer".

Your suggestion would make some sense were it not for the fact that what I quoted was part of the alternative to the whole board being compliant with 61493-3. We seem, yet again, to be dealing with a less-than-ideally-worded regulation in BS7671!

Kind Regards, John

 

[stillp]

I was responding to stillp's comment (which I continue to find hard to believe) that it is "quite likely" that a protective device will fail if housed in the 'wrong' enclosure

I CBA to check back, but if I referred to a wrong enclosure, I was mistaken.

I've checked for you. You wrote...

.... It's quite likely that they will pass the tests in one manufacturer's enclosure and not in another.

... which is what I regarded as rather disturbing.

The issue is not one of putting devices into the wrong enclosure, but is one of mixing components within an enclosure in a way which has not been type-tested. The enclosure is of course one of those components.

Fair enough, but are you still saying that it is "quite likely" that devices will fail the tests if they are in a 'mixed components' situation? If so, what do you mean by "quite likely"? I would have thought that, in normal usage, that phrase would imply a probability of at least, say, 1 in 10, probably much higher.

Kind Regards, John

Sorry, very remiss of me. I should have said that it is likely that they will pass the tests when incorporated into one manufacturer's assembly but not when incorporated into another's.
The term "quite likely", in the context of failure of a protective device, would imply to me (in the unlikely event of needing to quantify such a casual statement) a far lower probability than the 0,1 you suggest.

 

[stillp]

If a Chinese manufacturer produced a copy of an accepted/approved/'safe' product and were able to satisfy a reputable regulatory authority that their copy was, in all respects, 'identical' (to within whatever tolerance the authority required) to the established product, would you still have concerns about that product?

That would depend on the competence and rigour that was applied by the regulatory authority. Would that extend to, for example, examination of the production controls and supplier criteria?

Very much so, in the case of medicinal products. Even changes in key personal at the manufacturing facility, and certainly any changes in the supply chain of raw ingredients, will usually trigger a re-assessment/review of the product approval.

Kind Regards, John

How would they know, in the case of a product manufactured in say the Far East?

 

[JohnW2]

As I've said though, I believe that the more stringent requirements when the DB is under the control of ordinary persons relates to the likelihood that an ordinary person is less likely to react correctly to an incipient failure of the DB. In addition, installations under the control of skilled or instructed persons can be expected to be inspected and/or tested at suitable intervals.

Oh, are you saying that these problems that can arise as a result of mixed-brand protective devices are things that evolve gradually, give some warning of an incipient failure, and can be detected, before they result in harm, by inspection and/or testing? I have to say that such is not what I was imagining!

We are talking primarily about MCBs. How are these non-ordinary persons going to test the MCBs?

Kind Regards, John