Originally Posted by DJ-CHRIS
Their isn't enough juice on any of the rails in a PSU to kill you
this is true.
the exact phenomenon of monitors/PSUs killing people is to do with stored electricity.
inside the PSU there will be two large capacitors, (inside the monitor sthere are usually more).
the purpose of these capacitors is to act like small batteries, they store charge when the voltage is running at the usual level and release the charge when the voltage might dip from the rial supply, they are part of the voltage smoothing circuit.
Capacitors can store charge indefinitly, leaking only a small charge to the air overtime, so if you have a capacitor that have been charged then you'd find that it could discharge through you.
and depending how much voltage the capacitor was charged with will depend on how muh it discharges.
capacitors, (nulike batteries) can discarge almost instantly, so the current supplied would be a lot higher than usual.
anyway, for the purposes of a computer PSU shorting pins 5 and 6 (green/black) is safe, the voltage/current is so small as to not be a problem. in fact I'd wager that you could probably short the two wires across your tounge without any problems whatsoever.