How can I choose the size of wire which used at building depending on voltage drop

Post back with the distance and amps. I have asked to have this moved to electrical and lighting. Our expert there, tkrussell, will give a reliable answer. I wouldn't trust anybody else.

The information needed is:

Supply Voltage
Single Phase or Three Phase
Total continuous maximum load listed in amperes, wattage, KW, or KVA.
Distance of conductor.
Copper or aluminum wire.
Location of conductors, overhead, underground, etc.