Following on from this post, it reminded me of something I was going to bring up. I'll start another thread rather than hijack that one ...
One of the things that set me off thinking about this is that SBS are stating to replace their AC type RCBOs with A type - but at present only do a few sizes with C curve which are aimed (or at least, provided because they need them) primarily at EV charger installations.
So looking at a few sets of measurements (my house, mum's house, church) I see that most if not all circuits would take a C curve.
In fact, at mum's house the garage supply (20A to suit the existing 2.5mm² T&E cable) was swapped to C curve as the RCBO couldn't start many power tools without tripping. I'd initially assumed that this swap would be a problem, but looking at the figures on the installation certificate (it had a new CU and partial rewire) it was well within spec for a C curve breaker.
I've never seen C-curve MCBs commonly used - even where they would be suitable. My assumption is that this is the same reason - "everyone uses B curve, and it needs thought to use C curve" so no-one bothers doing the thinking required to see if C curve would be appropriate.I would hope that they won't ("become commonplace", unnecessarily), but I fear that aptsys may well be right, and everyone knows the reason as well as I do. Not installing them requires thought and a sensible/intelligent judgement, but fitting them can be done mindlessly.
One of the things that set me off thinking about this is that SBS are stating to replace their AC type RCBOs with A type - but at present only do a few sizes with C curve which are aimed (or at least, provided because they need them) primarily at EV charger installations.
So looking at a few sets of measurements (my house, mum's house, church) I see that most if not all circuits would take a C curve.
In fact, at mum's house the garage supply (20A to suit the existing 2.5mm² T&E cable) was swapped to C curve as the RCBO couldn't start many power tools without tripping. I'd initially assumed that this swap would be a problem, but looking at the figures on the installation certificate (it had a new CU and partial rewire) it was well within spec for a C curve breaker.