They are just angled bench sockets, we are trying not to cut the wall out as I said tastes change. and mounting them on a workbench that is fixed to a wall.
It recognises a 2.5mm² unfused spur supplying a double socket, but what exactly do you men by a "20A rated spur"? Are you just assuming that a double socket represents a maximum load of 20A?
Not to the same extent. It's obviously a matter of degree/judgement, since any multi-sockets circuit can only be 'designed' on the basis of a degree of guesswork - nearly all real-world sockets circuits (of any type) have enough outlets to theoretically allow a total of loads which exceeds the rating of the OPD many times over! The designer therefore has to make a judgement as to what is the "likely" use of the circuit.
As often discussed, there is a limit to the extent which one can (should?) attempt to anticipate incorrect things that might be done in the future. An FCU could be changed to a switch or JB (or a socket with a spur). An MCB could be changed to one of much higher rating ... etc. etc.
We've been through all this before, countless times, and no-one seems to really know the answer. According to the "Technical Data Sheet", MK double sockets are 'rated' at "13A per socket outlet", and when I asked their Technical Support people whether that meant that a double socket was 'rated' at 1 x 13A or 2 x 13A, he said he didn't know "because the Technical Data Sheets are written by the Marketing Department"!!
It's actually 14A + 6A, but that is the minimum requirement to satisfy BS1363. There is nothing to say that a manufacturer cannot produce a product which exceeds that minimum standard and 'rate' it accordingly.
Even if it were, as I said, a 'maximum' of that order only exists if one wants to follow the VD 'guidance', and follow that guidance even if the entire 20A load is applied at the very end of a 20A radial. As I also said, from the point of view of Zs (which is what really matters0, a 20A radial in a TN-C-S installation can probably be about 100m long.
Indeed so. Despite what I say above (i.e. even if one feels obliged to follow the 'VD guidance' in the most extreme of loading scenarios) , I don't think that even 30m would be particularly 'restrictive', since, in the average house, I doubt that any sockets would usually be more than 30m (even 'as the cable flies') from the origin of the circuit.
Can I ask why they use of 20 amp radials in a kitchen is not a good idea ? Its just that is exactly what tends to go in our renovations, one down one wall, one down another and one down the middle for the b loddy island... 20amps for say 5 appliances seems a lot in these days of a rated appliances.
Well, three 20A radials in a kitchen is obviously a lot better than one (or maybe two), which is not all that uncommon.
I'm assuming the cable is expected to be rated at at least 20A as installed. The same as the cable on a ring is required to be rated at 20A, but maybe that is just an assumption and not actually stated anywhere.
No, the requirements for the ring do not apply to the spurs.
Except that it isn't. 20A T&E (1.5mm²) is not allowed.
It is not stated anywhere - and is apparent for spurs to lights, fans and other similar low current appliances.
Without being overloaded, a 20A radial can only support one full size appliances plus smalls. Kettles are sometimes a full 13A, as are some washing machines and dishwashers. I don't think it's unreasonable to expext that two of these appliances may be drawing full power at the same time. Three is much less likely.
The wheeze with washing machines and dishwashers is that the energy rating only reflects the most economical cycle, which may not be the cycle people actually use.
Yes, that's what we tend to assume - but, as you say, it's only an 'assumption'.
Well, it's now you that is making an 'assumption'. As both plugwash and I have said, we just don't know, because the reg is not clear enough.
... and I wouldn't think i would be too difficult to argue that the intention of that was that the 20A minimum CCC applies to spurs from ring finals as well as the cable of the ring itself, is it?
No. I think it is obvious because you may use cable with a CCC of less than 20A.
For simplicity, I would make them as extension leads, 1.5mm flex to a single plug. We have literally 100's of lab benches made in the same way!
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