I've always heard that the longer your extension cord run is the thicker should be the wire. I have a 25' 50 amp land line cord attached to the coach. I have 2 extension cords about 25-30' each. One a 50 amp, the other a 30 amp. I also have converter plugs that will let me go straight from 50 to 30 to 20 amp. Ok, so if all I need to use is one extension cord, should it be the 50 or it doesn't matter ???