@arg appreciate your expertise - can I please pick your brain a further time
We have a split consumer unit, with lighting side not RCD protected, but main circuits side on protected RCD side. The consumer unit is in our garage, so circuits for main house disappear up the main cavity for distribution inside the house, but circuits for in the garage are surface.
I have identified a spare MCB, previously used for outside lighting, but now just terminated inside a junction box. This is on the lighting side of things, so no RCD protection, at least not from main fuse box. This all predates us and latest wiring regs but certainly should have been conformant at the time of install as it was all done when new CU was installed by the qualified electrician around 2000.
As we don't have the outside lighting any more, that MCB slot is theoretically up for grabs.
This is me just planning on what to ask a sparky to do. Not a done deal and obviously, what the sparky says goes. But it will form the basis of me getting someone into quote for the job.
Our PV goes into the RCD side of the house. Never felt happy this this as I could imagine that PV could still be producing power for longer than the RCD in that side of the CU takes to trip making the RCD ineffective until PV shits down. I am pretty sure that solar PV is also on its own 16A(?) RCBO but would need to double check. Touch wood, never had a problem with PV tripping.
So my thoughts are to ask the sparky to move the PV to the lighting side, which is non RCD protected (PV would still have its own RCBO) and use the now spare PV slot on the RCD side of the CU for a 32/40A MCB. Then, as per rest of garage, run surface wiring to front of garage where there was a mini CU with a type B/EV RCD. The wall connector can then be run from that.
Short of swapping out the whole CU, does this sound like a plan? I'm just not sure what the ratings are for the internals of these things. We have 100A main fuse.
Thankyou in advance.