BS7671 :) said:
'Fault Protection' - Protection against electric shock under single falt conditions.
In other words 'earth fault' - nothing to do with 'Overcurrent' protection. ....
I think what you meant to say above is:'Overcurrent' protection comprises 'short circuit protection' and 'overload protection' .... ..........which now means 411.4.4 makes perfect sense.
I think I was a bit too quick late last night to effectively concede that I had, whilst distracted, written nonsense. At least, in the coolness of day, I can see further confusions here.
Yes, what I should have written is what you say above and, yes, in some senses that means that 411.4.4 makes sense, but I think it actually leaves my original point intact. In fact, I think you are emphasising my point! As you say, 411.4.4 says that fault protection may be provided by an RCD provided that (NOTE 1) provided that the circuit has an OPD per Chapter 43 ('Overcurrent Protection'). As you say, overcurrent protection is nothing to do with 'earth fault' ('L-E') faults. In other words, it looks to me as if 411.4.4 allows fault protection to be provided by an RCD and does
not (even in NOTE 1) require that anything else provides disconnection in the case of L-E faults.
So, I'm back to my original thinking - and the fact that, whilst 411.4.4 appears to allow an RCD alone to provide 'fault protection', at first sight that is contradicted by 415.1.2 - which says that "the use of RCDs is not recognised as a sole means of protection and does not obviate the need to apply one of the protective measures specified in 411 to 414". However, whatever 415.1.2 was intended to say, as written it seems to be almost meaningless in practice - "one of the protective measures specified in 411 to 414" includes 'basic protection' provided by basic insulation. In other words, whilst 415.1.2 says that an RCD cannot be the 'sole protection', the implication of it (as written) is that an RCD plus basic insulation is not 'sole', and therefore is acceptable. In fact, as written, the only thing it would 'outlaw' would be to use an RCD as the sole means of protection of live exposed parts! At the very least, I still think there is a confusing apparent conflict between 411.4.4 and 415.1.2.
There are also a couple of other related things that I find very confusing. Firstly (and I've never noticed this before), a footnote to Table 41.1 in 411.3.2.2 (disconnection times) says "NOTE: Disconnection is not required for protection against electric shock but may be required for other reasons...". What on earth does that mean? - we are, after all, talking about the chapter on 'Protection against electric shock' (aka 'fault protection'), and disconnection is a pretty useful tool in the protection against electric shock!
Secondly, 411.3.2.6 says that if the required disconnection times can't be achieved, then supplementary bonding is required. It doesn't say anything about why the disconnection times are not met, and says nothing about the requirement for anything other than supplementary bonding in this situation. That seems very odd, and almost 'cancels' the requirements for disconnection times.
I really do think that there are some ongoing confusions!
Kind Regards, John.