Greetings all - returning to uk.d-i-y after a couple of years absence
(mostly due to work. grrr.) Glad to see many familiar contributors
still around.

Current project - kitchen extension and complete refit. Have a builder
doing this (I'd love to do it but just no time) & electrician to do the
electrics/certification (construction being done under Building Notice
application, so no chance of any Pee avoidance. I'd want a regs
compliant installation in any event).

One part of the work is to run SWA down the garden (about 15m) and
connect up the shed. Shed has small garage CU in it, with 30mA RCD, 6A
lighting ciruit MCB and 20A socket circuit MCB. 5 double sockets on the
latter and about 8 metres of 2.5mm^2 t&e in total.

Now, I'm pretty sure that I have read here before from the 'lectrical
cognoscenti that 2 radials into one MCB was unusual, but permissable.
Of course I can't find the post now... Due to the layout of the shed
workspaces & with thoughts of economy of installation, I'd prefer to
install 2 radial circuits rather than one ring, so this is how I wired
it.

Quick discussion with electrician today revealed he had a different take
on it, and that he didn't think that such an arrangement could be
compliant.

Does anyone have chapter & verse on such an arrangement?

Of course I could quickly adapt it to a ring, or even slot an adaptable
box or similar so that the 2 x radials go into that, and single t&e to
the shed CU, making it a single radial. But if I don't need to, I
really would rather not do. A single ring would normally be on 32A MCB,
of course, but is there anything fundamentally incorrect about putting
the circuit on a 20A MCB? (the cable would if anything be over-
protected in this arrangement, surely).

Also, I have an externally mounted socket, RCD protected. I'd rather
not have to run two separate circuits to the kitchen (one RCD'd, the
other not - for the fridge, etc), arguing that the external protected
socket makes the use of internal sockets for external portable equipment
very UNlikely. Are there other regs that come into play here?

On a final, OT, note - anyone working in The City know of any useful
bookshops or other retailers where I might be able to get my hands on a
16th edition OSG? Decent bookshops in The City seem to be a bit of a
rarity these days if my wanderings are anything to go by.

TIA

--
Richard Sampson