Mismatched MCBs C2 or C3?

[Murdochcat]

So in summary, mix and match is frowned upon and tbh there is absolutely no need for it these days.

In the case of an EICR inspection:

C2 for an installation which is “bodged” , or with obvious thermal damage
C3 for 3rd party unit

The end

 

[EFLImpudence]

The device is tested when in a particular enclosure - i.e. the test is how device A is housed in enclosure B

So you are saying that there are different criteria for similar products from different manufacturers.

 

[ebee]

I think what is being said is there might or might not be a mismatch of busbar connections between different brands of breakers and there might be a mismatch of hotspots ventilation between differing brands too.
Of course I think we all suspect that a few apparently different brands might also be actually manufactured as exactly identical in the same Factory but badged as different brands.
The problem is that the brands will only certify their own products used together and none of them appear to want to suggest any other brand as compatible bedfellows. It would need a group of turkeys to vote for xmas before that could ever happen

 

[JohnW2]

So in summary, mix and match is frowned upon and tbh there is absolutely no need for it these days.
In the case of an EICR inspection:
C2 for an installation which is “bodged” , or with obvious thermal damage
C3 for 3rd party unit
The end

For what it's worth that's essentially my view (and what you say about C2/C3 is, indeed, a repeat of what I've wrote).

However, I would remind you of my qualifications about the C2. Firstly, that whether or not it is given a C2 depends upon the inspector's judgement as to whether the nature and severity of 'bodging' is such that "urgent remedial action is required" and, secondly, that I don't think that any of this has got anything to do with the brand of device - i.e. If there is thermal damage, or bodging that the inspectors judges to "require urgent remedial action", then that would be C2 even if it were a manufacturer-approved device.

In my opinion, the frustrating (and in some senses 'sad') thing about all this is that it was all so 'unnecessary' probably initially arising out of 'commercial' considerations-since I find it hard to believe that manufacturers and relevant organisations etc. could not have agreed to make the devices 'interchangeable' had they so wished .... think, for example, of the ridiculous situation if only the same brand of BS1363 plug was 'approved' (by the manufacturer, with their 'vested interests') for plugging in to a certain brand of BS1363 socket!!

 

[JohnW2]

So you are saying that there are different criteria for similar products from different manufacturers.

No, not different criteria, but with the same criteria being applied to tests of different combinations of items being 'tested together' as a single entity!

 

[JohnW2]

I think what is being said is there might or might not be a mismatch of busbar connections between different brands of breakers and there might be a mismatch of hotspots ventilation between differing brands too.

Indeed - that and other similar are presumably the thinking about all this obsession with 'same brand' devices and enclosures. To what extent the 'type testing' is 'a solution looking for a problem', I do not know ... but what about your experience - have you ever seen or heard of a problem arising which you really believed was due to a device being of the 'wrong brand#, even though it 'fitted perfectly' and had been 'installed properly/?

As I've just written to Murdo, I think it's a great pity that this situation was allowed to arise.

 

[Murdochcat]

For what it's worth that's essentially my view (and what you say about C2/C3 is, indeed, a repeat of what I've wrote).

However, I would remind you of my qualifications

As you aren’t a practising spark I’m not sure your views are relevant tbh

 

[flameport]

So you are saying that there are different criteria for similar products from different manufacturers.

The tests are for the assembled consumer unit as a whole - not the individual components.
There are tests for individual components but those are entirely separate and unrelated.

Manufacturer A takes a whole selection of it's MCBs, RCBOs, AFDDs, blanks, SPDs and any other devices they have, assembles them into multiple configurations within it's various consumer unit enclosures, and then runs multiple tests and scenarios on all of those assemblies, such as running devices at full load, partial loads, at high temperatures, low temperatures, high/low humidity, applying various faults to one and multiple devices including moderate overload, earth leakage, short circuits with various fault current levels, arc faults, overvoltage and so on.
All of which is to ensure the devices all operate as expected in pretty much any combination they can be assembled in.

Doing this is time consuming and expensive. If problems are found with certain configurations then devices will have to be modified, and then those tests done again.
Repeat until everything works as intended.
Then you can sell the enclosures and devices to go in them as type tested assemblies, so the installer doesn't have to concern themselves with such things. They just buy the items, assemble according to the instructions and that's it.

If they wanted to confirm that devices from Manufacturer B could also be used, then repeat all of the above multiple times with various assortments of devices and enclosures from Manufacturer B.
For manufacturer C - repeat again but also including selections from A B and C. The quantity and cost of the testing increases exponentially with every added manufacturer, which is why no one does or ever will test such things.

The alternative to type testing is individual testing of each assembly, which is what happens with individually built control panels and similar. Fine for a small volume of what are often bespoke products. Not appropriate for mass market items which will be sold and installed in the millions.

 

[pete01]

So in summary, mix and match is frowned upon and tbh there is absolutely no need for it these days.

In the case of an EICR inspection:

C2 for an installation which is “bodged” , or with obvious thermal damage
C3 for 3rd party unit

The end

Exactly, as I said in post #2, 4 years ago

 

[pete01]

 

[JohnW2]

As you aren’t a practising spark I’m not sure your views are relevant tbh

Give it a break ... and I did write "For what it's worth"

I think you really should try to shake off some of your obsession with qualifications and occupations.. The majority of electricians are fine, but the very worst (and definitely dangerous) electrical work I've ever seen was done by a 'highly qualified' with 'decades of experience' (of 'doing what?' I was frightened to contemplate).

 

[Deleted member 142255]

Exactly, as I said in post #2, 4 years ago

Lol, and I thought they knew how to drag things out on screwfix. This lot make it a close run.

 

[JohnW2]

The tests are for the assembled consumer unit as a whole - not the individual components. ... There are tests for individual components but those are entirely separate and unrelated.

Agreed- and I essentially agree with everything else you go on to say. However, I would ask you the same question I've been asking people (recently, and for years) with virtually no useful answers ....

..... have you ever seen or heard of a problem arising which you really believed was due to a device being of the 'wrong brand#, even though it 'fitted perfectly' and had been 'installed properly/?

 

[Deleted member 142255]

View attachment 372376

Note to self - buy bigger bags of popcorn and more beer

 

[pete01]

..... have you ever seen or heard of a problem arising which you really believed was due to a device being of the 'wrong brand#, even though it 'fitted perfectly' and had been 'installed properly/?

Maybe no one ever has because all the evidence was destroyed in the fire....