I've been asked to size a cable for a large load - 630A.
With BS7671 in one hand and IET Electrical Installation Design Guide: Calculations for Electricians and Designers, 5th Edition in the other I'm working through the different derating factors.
The cable is not close to any other circuits so I'm working on the assumption that the Grouping Factor Cg is 1.0
Most of the other factors appear straightforward but there are two points that I'm not clear on...
"Buried Circuit Rating Factor" Cc
Consulting 433.1.1 (iii)
As these are all feeding the same load am I correct that the Grouping Factor Cg is still 1.0?