Need to run electric for a camper about 650 feet from my 200 amp service pole at the farm. I need 50 amps for the camper ac and such but I am worried about voltage drop. I am going to run the wire in pvc conduit due to the rocky soil. I can't find any reference to the distance of run relative to the wire size to use. Any help would be great. I really don't want to run a generator.