ZE at board/earthing alternatives

[Sintra]

You can't get a 150A BS 88 as far as i know 125A then 160A

 

[olly w]

Going back to the bosses comments it is permissible to use an extraneous conductive parts as protective conductors.....I don't make the rules.
543.2.6.
I think there would need to be a bit more investigation than "just take an earth from the nearest girder"
P.S. I have never done it and hope never to have to.
I'm going to hide from the bullets now.

 

[StokieSpark]

You can't get a 150A BS 88 as far as i know 125A then 160A

Sorry, really long day... 125A

 

[Sintra]

No probs mate but regardless the Zs on your sub main is way to high for the 160A MCCB protecting it.