Power and Earth Cable requirement 1

[Histor]

Hi,
I need to size the cable for 1.5MVA Emergency diesel generator. So I've considered 2500A Breaker and 4 Runs of 4x1Cx300 Sqmm (16 Cables) Power Cable and 1 number of 150 Sqmm Earth Cable.

Now Do I need to Consider more runs of Earth Cables?

 

[JezNZ]

Who can say?

You haven't provided enough information. Not even the voltage level and configuration (I assume this is LV in the 400-440V range, 3-phase).

First principles:
- How large does it need to be to guarantee that your protection operates in the desired time?
- How large does it need to be to guarantee that it can satisfactorily handle the fault current for the required time?

Followed by:
- How large does it need to be to satisfy applicable legislative and applicable engineering standards requirements?

Neither can be answer without knowing:
a) Your protection scheme and Neutral-Earthing configuration
b) Applicable fault currents
c) Your local legislation and design basis

I might be inclined to say that, from experience, everything looks in about the right proportions, but I couldn't give you a defined answer.