... one can argue that the regs themselves don't really offer a way of attaching a load >13A to a ring final, since it can't be done through any BS1363 accessory. I suppose it could just be a JB, but I suspect that many would probably question whether that would be compliant.
I don't think there's any argue or question about that bit - AIUI the regs don't allow anything but BS1363 accessories connected to a 2.5mm RFC on a 32A MCB. That's a fairly reasonable restriction in return for being allowed to use an "undersized" cable in the circuit.
If it's the strict word of the regs you're interested in, I think there actually is plenty to "argue or question". As has often been discussed here, although the regs say that accessories to BS1363 may be connected to a ring final (or associated spurs), there is actually nothing written which says that is an 'exhaustive statement' - i.e. the fact that it says that 'accessories to BS1363 may be connected..." does not necessarily mean (certainly doesn't say) that other things may not also be connected to a ring final. If it has meant "
only BS1363 accessories", it could easily have said so, but didn't. As has been discussed, JBs (not BS1363) are accepted on ring finals, and so are DP switches (e.g. grid switches, again not BS1363) quite often seen in spurs from ring finals (e.g. in kitchens)
But that's not what's being discussed here. The post I was querying inferred that the same limitation applies to a radial (in this case done with 2.5mm cable and a 25A MCB).
As above, it's far from certain that there
is such a 'restriction' in relation to ring finals, let alone radials. I'm not sure that your thinking that this is all to do with the 'undersized' cable in a RFC is necessarily right (although it obviously 'helps' in that respect). It is certainly allowable to have a point loading of at least 20A on a ring final (one double socket), and two double sockets side-by-side on a ring would facilitate more than the total design current of the circuit (32A) to be drawn from virtually a 'single point' on the ring.
Whatever, I'm sure you're right that there is no issue about >13A loads on a radial circuit. Provided the cable and OPD are appropriate, we're all familiar with much larger loads than that on radials (think showers and large cookers, for a start), and there's no reason why one cannot 'design in' a socket or three onto the same circuit, if one so wishes. However, as before, there obviously
would be an issue with running any load >13A via a BS1363 plug/socket or a 13A FCU.
But since I'm not familiar with the regs to that level, I was asking if there is in fact any such restriction applying to a radial circuit where the cable is of an adequate CCC and so doesn't need to use the exception applying to RFCs.
See above.
Kind Regards, John
