Mixed brand MCBs and EICR coding

[kai]

Crabtree Starbreaker and Square-D quickline boards have clip in breaker mountings.

 

[JohnW2]

I disagree, of course one can, if the time, trouble and money needed to control a risk is zero, then the magnitude of that risk does not matter.

That's obviously true, but the "time, trouble and cost" will very rarely be zero. There are countless CUs out there with mixed-make components, and there has to be a reason why that has arisen - presumably most commonly because there would have been time and/or trouble and/or cost in obtaining a correct-make device.

Fair enough. I have more confidence in (some) manufacturers than I do in most so-called 'independent' test houses, but that's just my personal experience.

An 'independent test house' is not really the same as a truly independent agency, regulatory body or whatever that has careful scrutinised a lot of data (usually from a lot of sources) and drawn expert conclusions. The problem with the matter we are discussing is that I have nothing other than your word that there is any data/evidence (rather than just theory) related to the matter in question - at least when an agency/authority has scrutinised data and drawn conclusions (and maybe 'approved' the product) one at least has confidence that data supporting the conclusions actually exists.

That's interesting, thanks. Where might that data be found?

In the case of medicines approved in Europe in recent years, you'll find it on the website of the European Medicines Agency. The documents you are looking for are called "European Public Assessment Reports" (EPARs), also/formally known as "Summary Basis of Approval" documents (click here for index) .

Kind Regards, John

 

[SimonH2]

I was thinking that if the plan is to mix & match, then you'd be limited to types clipped onto a DIN rail and with a screw connection to a prong on the live bus bar. Finding mix & match clip on types would, I'd have thought, be quite difficult - and I don't think I's go as far as swapping the prongs from a (say, it's one I've used) from a SquareD breaker to something else.

 

[stillp]

I have nothing other than your word that there is any data/evidence (rather than just theory) related to the matter in question

Quite, but that's backed up by a number of consensus-based standards and manufacturers' instructions, and is a lot more data/evidence than you can provide to show that there cannot be any ill effect.

In the case of medicines approved in Europe in recent years, you'll find it on the website of the European Medicines Agency. The documents you are looking for are called "European Public Assessment Reports" (EPAR), also/formally known as "Summary Basis of Approval" documents (click here for index) .

Thanks. Can you offer any explanation for a medicine not being listed there? When a medicine is available under different brands, are all the brands listed?

 

[Iggifer]

Crabtree Starbreaker and Square-D quickline boards have clip in breaker mountings.

But Square D are (or at least make a range of) standard breakers that just have prongs that screw into the incoming terminal, have a plastic lid over the prongs and then the prongs snap in. So still a screwed connection

 

[stillp]

I was thinking that if the plan is to mix & match, then you'd be limited to types clipped onto a DIN rail and with a screw connection to a prong on the live bus bar. Finding mix & match clip on types would, I'd have thought, be quite difficult - and I don't think I's go as far as swapping the prongs from a (say, it's one I've used) from a SquareD breaker to something else.

Deleted - too much information

 

[SimonH2]

That's obviously true, but the "time, trouble and cost" will very rarely be zero. There are countless CUs out there with mixed-make components, and there has to be a reason why that has arisen - presumably most commonly because there would have been time and/or trouble and/or cost in obtaining a correct-make device.

Would a lead time of a week and price of around £50 ex VAT count ? That's the case with the boards at work, which at 25 years since installation can't really be described as "ancient". Old yes, ancient no.

 

[stillp]

the boards at work

Are they CUs?

 

[JohnW2]

I have nothing other than your word that there is any data/evidence (rather than just theory) related to the matter in question

Quite, but that's backed up by a number of consensus-based standards and manufacturers' instructions, and is a lot more data/evidence than you can provide to show that there cannot be any ill effect.

I have never suggested that there "cannot be any ill effect", let alone offered evidence to support such a suggestion. None of what you say above really gives me any confidence that there necessarily is any data/evidence positively demonstrating the ill effects resulting from mixed-make protective devices.

Thanks. Can you offer any explanation for a medicine not being listed there? When a medicine is available under different brands, are all the brands listed?

As I said, EPARs will only exist for products which were first approved by the EMA in recent years. Generic versions of medicines that have already been approved will generally not have EPARs, since there will be no 'new data' relating to that product - the approval will generally have been granted on the basis of a demonstration that the new product is chemically and pharmaceutically 'identical' (adequately close to being identical!) to the already-approved product, with cross-referencing of the safety/efficacy data of that already-approved product. Some products have 'National', rather than European Licences/Approvals (sometimes in multiple Member States), in which case there will be no European EPAR. EPARs can sometimes take a long time (years!) to get published. Finally, as perhaps you have discovered, there seem to be a good few products approved by the EMA in recent years for which EPARs just don't seem to exist - and I can't give you an explanation for that!

Kind Regards, John

 

[EFLImpudence]

This from another thread:

It is actually a distribution board but if found in a CU would this have been type tested or is it not allowed?
Some Type 2, some Type B.

 

[JohnW2]

This from another thread: ... It is actually a distribution board but if found in a CU would this have been type tested or is it not allowed? Some Type 2, some Type B.

Why do you say that it's necessarily 'only a DB', rather than a CU? If it had been type-tested etc., it would surely qualify (per BS7671 definition) as a CU?

The answer to your question is obviously that (assuming the supply is ≤100A and under the control of "ordinary persons"), as far as BS7671 is concerned it would only be allowed if the arrangement had been type-tested. However, only the manufacturer could tell you whether a mix of Type 2 and Type B devices had been type tested. To some extent that will be dependent on chronology. If the board was initially (tested and) sold before the appearance of Type B MCBs, the initial type-testing obviously could not have included Type Bs, but they may have undertaken additional type-testing subsequently. If the board first appeared after Type Bs became available, I suppose they may well have included 'older type' (Type 2) devices in their 'type-testing'.

Kind Regards, John

 

[EFLImpudence]

Why do you say that it's necessarily 'only a DB', rather than a CU? If it had been type-tested etc., it would surely qualify (per BS7671 definition) as a CU?

I didn't say 'only' but because it was/is a DB and to prevent the comment that that is not a CU.

The answer to your question is obviously that (assuming the supply is ≤100A and under the control of "ordinary persons"), as far as BS7671 is concerned it would only be allowed if the arrangement had been type-tested. However, only the manufacturer could tell you whether a mix of Type 2 and Type B devices had been type tested. To some extent that will be dependent on chronology. If the board was initially (tested and) sold before the appearance of Type B MCBs, the initial type-testing obviously could not have included Type Bs, but they may have undertaken additional type-testing subsequently. If the board first appeared after Type Bs became available, I suppose they may well have included 'older type' (Type 2) devices in their 'type-testing'.

So - we don't know so what should we do?
I was more asking about the mixing of types rather than putting in a different box.

How do we know what is type tested other than as sold together?

 

[JohnW2]

I didn't say 'only' but because it was/is a DB and to prevent the comment that that is not a CU.

Yes, I realise that. I was simply making the point that all CUs are DBs, just a 'special type of DB'.

So - we don't know so what should we do? I was more asking about the mixing of types rather than putting in a different box.

I realise that, and said nothing about 'boxes'. However, as you say, we are somewhat starved of information....

How do we know what is type tested other than as sold together?

A very good question, and one which tends to get overlooked in these discussions. IIRC, MIs for CUs don't usually use the phrase 'type tested'. Maybe they do given an indication of what devices are 'recommended' but, to be frank, I don't recall having noticed them actually 'prohibiting' devices of other makes. I'll see if I can find some and have a read.

I think the main problem with this discussion is that stillp is taking a 'very strictly correct' position, but that common sense is probably not being given as much attention as it could be. There is no doubt that there is a theoretical possibility that the proximity of an 'untested' could (I imagine very slightly) influence the behaviour of a 'tested' device, but, as I have said, I find it very hard to believe that the devices would be so 'marginal' in their design that this would be of any consequence in a domestic CU. Let's face it, for example, a B6 of the correct make is required to work satisfactorily in any orientation, even if sitting next to a fully-loaded B45 or B50, and over a wide range of ambient (and operating) temperatures and altitudes. If (as one would expect) it can cope with all of that, I find it very hard to believe that the proximity of a 'wrong make' device, or the fact that it was in the 'wrong enclosure', would, in practice, have any appreciable effect on the device's performance (or well-being).

However, having said all of that, and despite what BAS seems to think/imply, I would never 'advise' anyone to used mixed-make devices, and nor would I install a 'wrong make' one in anyone else's CU (other than as a temporary measure). However, as far as I am personally concerned (i.e. in relation to my own installation), I am far more concerned with such issues as how well conductors have been terminated in the devices than whether or not the devices are 'the right make' (assuming they 'fit' {again, in common sense terms, rather than stillp's 'micrometer' view}).

Kind Regards, John

 

[securespark]

Err....?

Bugger, I've got the wrong thread again.

I assumed you would all know what I meant.

Happens to the best of us. Shows you're getting old!!!

 

[EFLImpudence]

Too late for 'getting'.