Mix and Match on MCB's

[nickblake]

I have noticed several times that different makes of MCB's are being used in boards etc ,did you know that in the manufacturers instructions it state only use their make of MCB , as you have mixed and matched MCB's and if something happend where would you stand, just a thought chaps

 

[IQ Electrical]

Apart from any warranty, you would sacrifice compliance with BS 60439-3 and the UK negotiated ZA annex which allows us to use the short circuit capacity of the BS1361 service fuse (16kA) on single phase installations.

 

[Marvo]

Why is it considered a problem to mix different makes of MCB's if their KA ratings, curves and current ratings are correct and they are of compatible frame size?

 

[roukel01]

There is now something in the regs (cannot think where right now) that states "equipment should be fitted according to manufacturers instructions) and therefore if the instructions state use only their MCB's then it is a non compliance, however there are some branded MCB's that are identical to one and another and in that case, I wouldn;t worry about it. I have seen some retro fitting where CU's have been cut and altered in all sorts of ways to squeeze an MCB in that isn't made for that particular board.

 

[SirKit Breaker]

If it fits properly, then i will mix and match. Generally only use Wylex anyway. The manufacturers will say use only their breakers wouldn't they. Pretty much the same as Ford saying use only genuine Ford Parts on my van........

 

[IQ Electrical]

If it fits properly, then i will mix and match. Generally only use Wylex anyway. The manufacturers will say use only their breakers wouldn't they. Pretty much the same as Ford saying use only genuine Ford Parts on my van........

I'm not often one to defend the manufacturers but in this case, it is the British Standard that dictates how compliance with BS60439-3 is achieved, if you're sad enough to read it, you'll see why and what these consumer units and associated protective devices are subjected to.

 

[Darkwood]

mixing and matching carries the risk of poorly fitting mcb's rcds or problems with the cover, although if the physical dimensions are a match and the busbar clamp is seated correctly when tightened then its shouldn,t be a problem and is safe to do so, and some circuit breakers are made by the same company with only a name difference..... Schneider for example are responsible for making Merlin Gerin amongst other common brands but are rebranding their Merlin range as Schneider so exactly the same part but just different name.

 

[Marvo]

Yeah, seemed an odd rule to me. I just searched the South African regs and there's no such rule here but our regs tend to follow the ISO regs more than the BS regs.
DIN mounted breakers should all be compatible in the same panel if the frame sizes are the same. Maybe the American brands follow different frame sizes like motors come in NEMA spec and ISO spec and their mountings are incompatible. This would be pretty obvious though.

 

[Amp David]

I never seem to be able to make them fit properly. Always tend to stick with the same make. Looks more professional too IMO