split load kits

[333rocky333]

It just seems strange to me and unnecessarily pointless to have such a small part joining a 16mm² conductor to the neutral bar.

I agree, and I would possibly be tempted to fit a ferrule or as you said cut the pin bit off.
However sometimes you have to trust the makers know what there doing I suppose,
That said some of the consumer units ive seen the neutral bars are so thin and massacred with holes they barely look able to take a decent load and even the Live busbars tend too use one prong nowadays and thats sometimes not that large.

 

[JohnW2]

I agree, and I would possibly be tempted to fit a ferrule or as you said cut the pin bit off.

FWIW, me too!

However sometimes you have to trust the makers know what there doing I suppose,

It would be nice to think that, but the more I see of this world, the less I trust anyone (even if they should be trustworthy), particularly when I have doubts about what they've said/done! MK are usually pretty responsive to questions, so maybe someone should ask them to comment on this issue?

That said some of the consumer units ive seen the neutral bars are so thin and massacred with holes they barely look able to take a decent load and even the Live busbars tend too use one prong nowadays and thats sometimes not that large.

That's also all very true - and I'm not necessary sure I 'trust' them about that, either!

I think that the main point, and 'saving grace' (and I imagine that this is what you were getting at with your earlier comments), is that there are such large safety margins built into most of the 'rules' to which we work that one can often 'get away with' things which outside of those 'rules' and far from ideal. However, safety margins are there for a reason, not to be 'eaten into' by manufacturers or designers!

Kind Regards, John

 

[JohnW2]

I also understand what you're saying, but it's not the way we are meant to think (pushing the limits of current-carrying up towarads 'burning out' point). Sure, a 100A fuse wire (~3mm² CSA) will carry 100A 'indefinitely' without 'burning out'. However, if I suggested to you that it would be acceptable to have a couple inches of 3mm² CSA cable (if one could get it!) in the middle of a 25mm² 100A submain, I would expect you to regard me as crazy. Yes, it shouldn't 'burn out', but clever people have worked out what they regard as maximum safe current-carrying capacities for conductors, and that maximum is very much under 100A for 3mm² CSA. The maximum current they feel is safe/satisfactory is obviously far below that which would cause the cable to 'burn out'.

The graph below (assembled from what data I have to hand) illustrates my point. For whatever reason, and for better or for worse, the maximum currents that BS7671 says one can safely pass through ('are allowed to pass through') a conductor is roughly between one-eighth and one-sixth of the current that will 'burn out' the conductor (the fusing current). The graph also illustrates that, as we know, 'fuse ratings' are roughly one half of the current which will 'burn out' the conductor in the fuse.

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• JohnW2
• 6 May 2013
• 1

Kind Regards, John