Garage Sub Main BS1361

[slowrunner]

I am planning to run 6mm SWA from a main DB which is protected by a 40A fused switch. The SWA runs to a garage and is connected to a BS1361 40A, it then goes into an RCBO protected sub main board. Is the BS161 necessary at the sub main when there is 40A protection at the source?

Any advice would be greatly appreciated.

 

[Engineer54]

Hmmm, ...i have just read your OP again and i'm now confused or i'm missing something!! So which is it, ...are you installing this 6mm cable or is it existing?? Make you're mind up!!

I am planning to run 6mm SWA from a main DB which is protected by a 40A fused switch. The SWA runs to a garage and is connected to a BS1361 40A, it then goes into an RCBO protected sub main board. Is the BS161 necessary at the sub main when there is 40A protection at the source?

A DIYr (previous owner) made it all a bit complicated not least, not connecting any external earths to the main ET of each board! All sorted with 3 new metal sub mains all containing RCBOs. I am just about to be assessed by NICEIC and wondered about BS1361's. The sub main supply goes from house and splits underground - one sub going to garage and the other to workshop.