I find it kind of amusing that among all the stated gages (sizes) no one mentioned the kind of wire (solid vs stranded) you should use. Although, either would work, I have yet to see a power supply with solid wire. Get stranded wire if you can. The solid bends (and stays bent) too easily. Oh yea, get 18 gage for molex, and 20 gage for three prong fan connectors.