Situation: Meter is in the garage (outside thermal envelope) with a small CU for the garage plus (planned) henley blocks connecting fused SWA runs to ASHP, shed, and into the house. 

It will be about ~20m of SWA to bring the mains in through a wall, through half the house and to the main CU (on the first floor landing, mostly chosen for shortest distance radials for all lighting). 

 

Ordinarily it would be 3 core x 16mm SWA with 80A fuse. I'd like to through in an extra core incase I add battery storage in future and want to have a separate "backed up" supply in addition to the direct grid connection. Question is should this additional supply have independent L & N, or can they share Neutral?

Basically can we get away with 4 core (or even 3 core if running a separate earth!) SWA, or does it need upgrading to 5 core?

 

(I will of course discuss this with the electrician, but I don't yet have that conversation and I'm trying to do my research in advance of that, as I imagine this is not a usual request) 

 

I think it’s easier to run separate cablingakea it easier to make changes.

 

combining multiple supplies in 1 cable leaves you open to the regulation bashers who if they see something non standard advise it’s unsafe.

 

I think a schematic at the incomer would be useful