After further inspection, this system was jury rigged for illegal back feeding with a generator. It feeds back through two parallel 200 amp panels. They used, what looks like, 10 gauge 3 conductor stranded wire. The colors are black and green for the hot legs and white for neutral. Apparently they got by with this setup. I have no idea if an Rv was ever hooked up to this system or if back feeding was the only purpose. It back feeds through a 240 volt 30 amp breaker in each box wired in parallel. I disconnected one of the boxes so that I can feed the receptacle through the other. Still have no equipment ground.
I may be better off using the three wires and installing a 30 amp setup with a ground.
