OP
ash2020
I guess 16 will do, it's a smallish flat. I wasn't sure about being able to use the armouring for the main earth. Are you saying it's not enough? The calcs for it are mind boggling. (543.1.3 17th ed) How the hell do you work out the CSA of the armouring?
And is I in the equation the same as max PFC?
And is I in the equation the same as max PFC?