What size wire needed for 50 amp service 800 feet away 120 volt RV Trailer 3600 watts plus a security light or outdoor outlet What size breaker at the supply disconnect receiving panel disconnect?

Answer 1

A 500 MCM copper conductor will limit the voltage drop to 3% or less when supplying 50 amps for 800 feet on a 120 volt system. 500 MCM wire diameter is 1/2 inch. As you can see there will be trouble getting that size wire into a 50 amp breakers lug. On installations like this to offset the voltage drop at such a low voltage, a transformer should be used at both ends. The first transformer to raise the voltage and the second transformer to lower it at the 800 foot end. If you use two 480 volt Transformers a #1 wire can be used between them.

A #1 copper conductor will limit the voltage drop to 3% or less when supplying 50 amps for 800 feet on a 480 volt system. By increasing the voltage you can see that a smaller wire size can be used.

On an installation of this nature, a primary line should be brought to the RV site and a service distribution panel established at that point and any RV vehicles can then be fed from that service.