what will kill you best
To all people arguing what kills and what doesn't (current vs. voltage):
If you're still young at heart (as I once was), you can go on a country ride and stop by a pasture with an electric fence. Grab a 2 ft long green (still moist, not dried out) grass blade by one end and rest the other end on the fence. You shouldn't feel anything. Slowly slide the grass blade towards the fence. At some point you should feel a somewhat unpleasant pulsed sensation. It will get stronger the closer you get to the fence wire. (If you are within 1 inch of the wire and still don't feel anything, the fence is OFF, or your grass is dead dry: abort.). If you did this experiment with a 10000V transmission line, you would likely be dead and learn a valuable lesson.
What protected you is the combination of your skin resistance, the (adjustable here) resistance of the grass blade, and the internal resistance of the fence generator. There is also pulsed, limited power nature of the generator, but let's not complicate things. The 10000V transmission line has pretty much no limits of its own. A capacitor charged to 10000V is also not likely to kill you because of the limited energy it can store and deliver.
Now, you can grab a 12V battery, one terminal with each hand and won't even notice. This battery could deliver over 100 Amps but here nothing happens.
You need a combination of sufficient voltage and low enough total path resistance to deliver the killing jolt. (Yes, it has to go through the heart. Time also matters.)
The resistance of your skin protects you up to about 40V. (It's just a rule of thumb, don't sue me.) Above that, please treat all wires as if they were spinning propellers.
So to conclude, yes, for academic purposes, it is the current through the heart of sufficient duration that kills. But when you face an exposed wire, for your safety you should mind its voltage. You will rarely know what limits are set in the generator circuits.
Poorly informed speculation:
Curiously, I used to think that you are probably more likely to be electrocuted by a household voltage of 110/220V than with a 10000V line because before your hand can get close enough to the 10000V line to convulse and latch on to it, it will arc through (high resistance) air gap of a few inches giving you a nasty warning.
BM
(edits in italics after learning from the wiser post below)
Last edited by balsa model; 21st Jun 2007 at 22:52.