Wolfgang.,
I will add little more comment with common North American conductor size most of the 200 A serivce typicaly use 120mm² { 4/0 AWG } unless speced in NEC code or local code which it will bump up to 150mm² { 300 KCM } but the 400 amp service the conductor will work in two way either single 240mm² or twinner 120mm²'s aka parllel set up and this is based on copper conductors with alum conductor it will bump up one size larger.
Also there is other code is the distance of inside the building once it enter the building we have to by X number of feet or meters before we have to add a outside disconnect switch { either breaker or fuse } all it depending on local / state codes.
As far for conductor colour codes it pretty much standarized for majorty of USA { Typically for 120/240 volts single phase will use black , red for phase conductors white is used for netural and green for earth }
Three phase will varies a bit depending on voltage and if wye or delta connection. { there is a colour chart in this fourm I have to find it one way or other }
Merci.
Marc
