I recently changed my wire out. I was using 10 gauge wire wire and was making around 89 watts on my homemade 72 cell solar panel. After upgrading the wire to 10 gauge landscape wire the is uv resistant and bury able wire with 130 strands. I got some great results. I improved it to a wopping 110 watts on this video but I have seen 112 watts. I dont know why this wire is not approved for solar but it should be its more than adequate for solar panels that aren't on a roof. I would say it is the best for yard displayed solar panels.

Part 1

http://www.youtube.com/watch?v=zheAgbkE9E8

Part 2

http://www.youtube.com/watch?v=McWNOjdbfvQ