BTW, for those looking to wire up two server power supplies in series to make 24v output, you can float the DC ground on one of the PS units instead of floating the AC ground. Doing this allows the cases to touch. Safer also, although I am in no way shape or form an electrician so read up before doing this. Also, you have to open the case which exposes you to high voltage (potentially deadly) shocks from the caps if you touch the wrong thing. Again, read up before attempting.