Quote Originally Posted by AndyD View Post
The length or the run becomes a problem because of volt-drop. Yes, if the cable doesn't enter conduit anywhere along its run then and no there derating factors are applicable then a 10mm cable will suffice for a 65A load.
Talking about derating ... I had to do the calculations for an 800 amp supply ... 150 metres long ... everything was on track until the cables got to the underground duct ... that 30 m piece in the ducts makes a huge difference to the cable calculation.