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EICR C3 mixed manufacturer breakers

Martyn
I know this will have been discussed in the past but we are on Amd 1 of the 18th now so I thought I would renew it.


The Best practice guides list mixed manufacturer breakers in a consumer unit or distribution board as a C3.


As far as I am aware Bs7671 does not have a Reg on it beyond manufacturers instructions and given EICR's are based on this standard perhaps it is justified on that basis.


Most on here will be familiar with the 16kA 'rule' in BSEN61439 Annex ZB or its predecessor BSEN60439 Annex ZA


I avoid C3's like the plague because they give all the wrong signals to a client and clearly by definition are for things which are a breach of the regs, I'm not too keen on the insurance risk of a C3 either.


My question here would be what fault rating can one apply to an enclosure where there are mixed breakers given a manufacturer will only have certified their equipment with their devices?


Enjoy!


Martyn
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    Interestingly, WISKA also state that the enclosures I refer to have passed the 'glow test' too.

    Personally, when it comes to a high energy disintegration of an overloaded mcb, I would reckon that all enclosures, be they of metal or plastic construction, are built to the same standard in terms of their ability to withstand a violent discharge and to contain the fall-out.

    Mcbs are now all pretty much made to BSEN 60898 so should have that commonality too,

    A cynic might suspect that the manufacturers are just doing what manufacturers do - protecting their revenue streams by utilising a measure which includes some dubious pseudo-scientific reasoning behind it.

    When it comes down to the hard science, exactly what is it that may cause a catastrophic failure if 2 mcbs from different makers are sitting happily side by side in an enclosure?

    Let us say for the sake of the exercise, that both mcbs have the same form factor, that the top and bottom terminal spacings are identical and that the busbar is not deformed during tightening.

    What's to go wrong?

    Just exactly how can a mcb from maker A undermine an enclosure and the other mcb from Maker B when they are all fitted together?
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  • 0
    Interestingly, WISKA also state that the enclosures I refer to have passed the 'glow test' too.

    Personally, when it comes to a high energy disintegration of an overloaded mcb, I would reckon that all enclosures, be they of metal or plastic construction, are built to the same standard in terms of their ability to withstand a violent discharge and to contain the fall-out.

    Mcbs are now all pretty much made to BSEN 60898 so should have that commonality too,

    A cynic might suspect that the manufacturers are just doing what manufacturers do - protecting their revenue streams by utilising a measure which includes some dubious pseudo-scientific reasoning behind it.

    When it comes down to the hard science, exactly what is it that may cause a catastrophic failure if 2 mcbs from different makers are sitting happily side by side in an enclosure?

    Let us say for the sake of the exercise, that both mcbs have the same form factor, that the top and bottom terminal spacings are identical and that the busbar is not deformed during tightening.

    What's to go wrong?

    Just exactly how can a mcb from maker A undermine an enclosure and the other mcb from Maker B when they are all fitted together?
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