I also generally agree with what Cedarhill wrote with one exception and several assumptions.
You will have to get the power out and back, so the total wire length is actually 130 feet, not 65.
The assumptions are that the wire is copper, not aluminum and solid not stranded. If these are not correct they the voltage drop will be slightly higher, but still safe.
Thus, the actual voltage drop will be approximately 4 volts at full load.
Good engineering practice is to design for a worst case of 5% or with a 120 volt source 6 volts.
I just stumbled on this thread after several days and read Dave's reply. I believe he is correct. I was off by a factor of 2 in this instance because in the original situation, there is not likely to be a "bonding" connection to earth ground at the far end to provide an alternate current path. All the current will return through the neutral wire.