It's the volts that jolts, but the mills (milliamps) that kills.

240v mains won't usually kill you so long as you don't manage to create a situation in which you can't let go or turn it off. If you have a weak heart it might. If you hold one wire with your left hand and one with your right, then it can be dangerous because the current crosses the chest (and therefore the heart).

240v can give you a nasty burn that if deep will take a long time to heal. Been there, done that. If you fiddle with electrical stuff enough, sooner or later you will make a mistake and get a good belt, but you usually survive and learn.


Let's not get paranoid here. What you really do need to worry about is 3-phase and if you get two bits of equipment on different phases you can get 415 volts between them. And the maths of it is a whole different ball game so a mistake becomes likelier. Unless you are a professional, do not do 3-phase!

Take extra care with even 240v in kitchens - you are surrounded by good conductors, and good earths. I once bought a house where the previous owner had succeeded in wiring up a spur to feed the ignition circuit in the gas cooker with phase and neutral reversed (and no earth at all). And it was next to the sink. The really really worrying thing was that he was a nuclear engineer, and if his standards were as high at work, the consequences did not bear thinking about.

Over here 110v is used as a safety level voltage for site work (big step down transformers) on the basic theory that 110v is not (all that) likely to kill, even among muddy puddles.