calculation of copper rod area

Dear all..

i need a calculation for the copper required to deliver 45 amp current..!

plz help me out with proper mathematical approch..

i am going to design water load for 10kw systems..

v=230Vac
i 44 amp...

reply with copper required..?

go thru
http://circuitcalculator.com/wordpress/?p=75/

http://www.tlc-direct.co.uk/Book/4.3.9.htm