Any black wire works for the connection, not jsut the wire specified. The green wire is a 3.3V lead to the motherboard, used for processor power I think. All the black wires are ground wires, so providing a physical bridge between the green wire and a ground wire makes the PS think there is a mobo and proc on it, and it starts. I use a 230 out of my case for testing Baybus setups that I build for my friends, I replaced it with a 330 Enermax, really quiet.