I'm a little late to this discussion but just recently came across this thread and thought I would add my 2 cents.



Typically the ESD (electrostatic discharge aka ‘Static Electricity’) 'human body model' testing is 8,000V touch and 15,000V air gap. This is used to test electronics for susceptibility to ESD. You rub your feet on the rug and zap a sibling... that's a very respectable amount of voltage that you just generated.... but there is essentially no current and "Current Kills"... It only takes something like 6-20mA (don’t recall the actual amount) through the heart to kill. Wall warts typically supply 250mA to 2A. Batteries will source all the current that they can. As long as there is minimal resistance along the path of electricity and you send 20mA through the heart... DANGER is possible. Using an electrolyte rich fluid (like salt water) and placing your hands in a bad way, it could very well put you at risk. Granted your skin will act as impedance... but it all comes down to Ohm’s law.



What I think ‘_soapy_’ and ‘laserage’ are discussing further down is if a bad setup is there and the cheap little wall wart is past its nominal operation… it could have problems and source more power than a battery could. Given how cheap those things are, that is definitely a possibility.



Like I said, my 2 cents... ehh maybe my 1.5 cents. =)