cable size

[jimelec]

what size cable (3-phase armoured + neutral) would you recomend to carry a max. of 2000 ampere. copper,
that is

 

[plugwash]

It depends on many factors among them how long the run is, what the protective devices are, what the upstream Zs is, what volt drop is tollerable (which relates to both national standards and what voltage the system is.

To put it bluntly you need an electrician who understands working with such high currents.