I buy 100 foot extension cord when they're on sale number, 12/3 conductor wire size. I can get them for as little as $15.00 and they come in different colors. I get several different colors and use yellow for air conditioners, orange for lights, black for wall plugs (120 volt) and green for 12 volt. They are UL approved and very flexible. You need to tin the ends when you hook them up to your main and on other connections use High lugs. Use an indent sqeezer to make good connections. You can buy 100 ft. cords with plugs on them cheaper than you can buy the wire by the foot. I use about 500 ft. of wire on a coach....This shows how wires are run in the roof. Run them were they will come down the wall to the fuse panel.
... Can to big a wire be bad ? My plan is to use the 10 for everything...