On 16/11/2019 00:24:39, Tricky Dicky wrote:
I spoke to the BCO today and the outcome of the conversation is that
he insists I include a Surge Protection Device (SPD) in the CU and
looking into the calculation required to avoid inclusion and the faff
collecting all the info it is probably easier and gets the job moving
just to fork out the £44 and be done.

So this is hopefully the final layout of all the protection devices
in the CU:

https://www.dropbox.com/s/vdv6ch8q1p...yout.docx?dl=0

AS the SPD is not connected to the busbar I have included it at the
end of the first section containing the Garage MCB and the two RCBO
devices. The issue is that it needs feeding from a MCB 16 - 32A. The
manufacturers recommend a 32A ring main. So does it matter which of
the two devices as indicated on the diagram is used?

Finally, I have added a separate isolator switch and planned
initially to feed the tails from it into the bottom of the CU but
would now like to fit a socket below the CU and with not much room to
play with it would be convenient to feed them through the top? There
are suitable knockouts in the top and the instructions say top
feeding is possible but with the convention being to bottom feed and
CU is situated below a kitchen worktop would anyone raise any
objections?

I know I should have asked the BCO but had other things on my mind
and I do not want to get into another conversation that will cost me
money!

While technically you have 2 lighting circuits on separate RCDs, I would
be tempted to split the lighting load more evenly between the 2, not
just the kitchen on one RCD.