Its 3 phase and N bernard so a bit more copper
Drat, I should be more carefull
2.5 mm £70.50
4.0 mm £100.00
difference £29.50
Even 5 core 4 mm would not be that much extra 3 phase Neutral and Earth
oops, container, big metal box, earthing might need a bit of good design. Safety devices to prevent accidental lock in of employee or boss.