Mismatched MCBs C2 or C3?

[Robin0577]

Square D MCBs fitted to an MK board...

They do physically fit correctly, so there has ben no hacking of the front panel, or bending of the busbars, so no IP breach or poor connections have been caused.

Would you code it C2 or C3?

 

[pete01]

If they fit perfectly C3 if it's a bodge C2

 

[Murdochcat]

popcorn at the ready

 

[Jurassicspark]

C2 IMHO.

 

[Jurassicspark]

Different make of a MCB only breach manufacturers instructions however a consumer unit will not comply with BS7671 if filled with different makes. Every different type MCB are type tested to their breaking capacity with their own make of devices.

Quick think, the exit point for the arc during a fault current is also manufacturer specific. They will insure nothing impedes this in there consumer units. Fitting different devices in a consumer unit could impede this.

So its a tasty C2.

 

[pete01]

If it fits perfectly there's no immediate danger and it's not potentially dangerous (is it) but you could improve it if you wanted to.

 

[Deleted member 142255]

https://www.electricalsafetyfirst.org.uk/media/mi1oqkur/best-practice-guide-4-issue-7-1.pdf

 

[pete01]

 

[Deleted member 142255]

 

[pete01]

It's a shame we wont be like this chap this time

 

[Deleted member 142255]

It's a shame we wont be like this chap this time

We could be lol. @Murdochcat got his popcorn out ages ago

 

[Murdochcat]

So what happens with mixing badged products ??

 

[JohnW2]

To throw another popcorn-eating cat in amongst the pigeons ....

I'm by no means convinced that BS7671 actually requires anyone to have a Consumer Unit (i.e. a 'type-tested' DB). In the case of a single-phase domestic installation of no more than 100 A it offers some 'dispensations' if one does have such a ('type tested') CU, but I don't recall (I'm distant from my copy, so can't check at the moment) it saying that having such a DB is 'required' in that situation.

Mixing devices is undoubtedly always going to be 'contrary to MIs' (for commercial reasons, if not others ) but, again, BS7671 no longer requires compliance with MIs, merely that they should be 'taken into account'.

If there are things 'wrong' or iffy within the CU (physically poorly fitting devices, thermal damage to devices etc.) then that obviously needs to be coded accordingly, but if there are no such problems, I can see that some might try arguing that it should not be even C3, and certainly not C2

 

[pete01]

To throw another popcorn-eating cat in amongst the pigeons ....

I'm by no means convinced that BS7671 actually requires anyone to have a Consumer Unit (i.e. a 'type-tested' DB). In the case of a single-phase domestic installation of no more than 100 A it offers some 'dispensations' if one does have such a ('type tested') CU, but I don't recall (I'm distant from my copy, so can't check at the moment) it saying that having such a DB is 'required' in that situation.

Mixing devices is undoubtedly always going to be 'contrary to MIs' (for commercial reasons, if not others ) but, again, BS7671 no longer requires compliance with MIs, merely that they should be 'taken into account'.

If there are things 'wrong' or iffy within the CU (physically poorly fitting devices, thermal damage to devices etc.) then that obviously needs to be coded accordingly, but if there are no such problems, I can see that some might try arguing that it should not be even C3, and certainly not C2

What code would you put? If any

 

[Murdochcat]

There is no doubt in my mind that BEEMA can up with a plan to protect their businesses and freeze out random suppliers who could and did sell cheaper products. BEEMA we’re able to use their influence to get the regs steered in their favour and of course this meant changed he’s which helped “justify” new amendments to the regs.

10+ years ago “dolly mixture” boards were VERY common, and to an extent are still happening now - which is poor to say the very least

Best practice would always be to fit the same product set in the same enclosure - which I would always do as far as I could

I have seen some shocking examples of botches, the worst being an inverted mcb so it appeared off when on and vice versa