On Mon, 5 Feb 2018 16:11:25 +0000
John Rumm wrote:

On 05/02/2018 14:18, wrote:
On Monday, February 5, 2018 at 1:28:04 PM UTC, John Rumm wrote:
On 05/02/2018 10:33, wrote:
Hi All,

I have a Wyler 12 way split load CU (NHrS12SL).

For various reasons, I will be having a qualified sparky do the
work, but wanted to check my options...

Currently our CU has most of the power circuits on the RCD side,
and 3 lighting circuits (which could maybe be reduced to 2
(combine the 2 downstairs circuits into 1 (its not a mansion).
And the immersion is also on the non RCD side.

I am thinking it is time to give at least the lighting circuits
RCD protection, but would like to avoid the cost of a new Box
(which would allow 2 RCDs).

Any particular reason for wanting to change?


The electrican who has been making ammendments to one of the
existing lighting circuits saus that he HAS to put it on RCD in
order for it to be regs compliant.

Ah, ok did not realise you were altering the existing circuits. If
making changes then yup they generally ought to be to the new rules.

(although I have at the back of my mind some guidance about this not
being an absolute requirement for some instances of lighting
circumstances - i.e. the requirement only takes force for significant
alterations to the circuit)

I wondereed about doing all the lighting circuits while I was about
it. Wylex "say" that all circuts run under plaster should be RCD
protected (well, they would wouldn't they),

They would, because they should. i.e. its not the fact that its a
lighting circuit that matters, its the fact it has unprotected cables
buried less than 50mm into walls.

and if possible I'd
rather not have all the lights go out together, so a bunch of RCBOs
on the non RCD side seems attractive.

Yup, you certainly want lighting spread over more than one circuit.



It can get interesting when the up and down circuits share a neutral,
generally on the landing light.