sizing 3 phase supply to/from 50KW solar array

[thegasguy]

Hi all, I have been asked to run a 3 phase supply from a nearby service head to a new DB servicing a solar array to be fitted on a riding school roof.
This is to take the electricity generated back to the grid. A proper MCS contractor is doing the array.
The problem I have is that the array is rated at 50KW peak( at 230v) which I make 200 amps plus!
The sevice head is a standard 100 Amp supply.
How can I (1) be sure the existing incomer is not going to be overloaded and (2) work out the size of 4 core armoured needed to link the service head to the new DB where the installers will make their connection?
The solar boys don't want to know about anything beyond their final 'box'
Thanks,
thegasguy

 

[BruceB]

I calculate 50kW as 72A per phase with 3 phases.

The solar people must spec the cable for you because if you decide the size and then there are voltage drop issues and the inverters cut out regularly then you will have an argument on your hands.

 

[tonyblud]

Thank you BruceB, I agree on 72A per phase max load.
The solar people seem strangely unable to calculate cable sizing! I am digging into who designed the system today, and whether they know what they are doing.
This reply may come from "tonyblud" (me as well) as I can't get into the forum this morning as 'thegasguy' for some odd I.T. reason. I have emailed 'Dan' at the forum to help me get back in.
Thanks again.