Off 240 I've had two, I am a cable jointer and my electrical gloves developed a hole, touched the exposed live core and got a poke. Worse one was off the house electrics, changing the sockets in an upstairs bedroom for metal faceplate ones, isolated the upstairs socket curcuit and started changing them, got a couple done moved on to the next one. Unscrewed the terminals and pulled the socket off, grab hold of the LIVE and NEUTRAL at the SAME TIME only to find out the hard way that it it still live and is the only socket upstairs that is fed from the downstairs circuit! Loads of swear words later and after isolating the entire consumer unit to be pedantic, socket was done. Only time I didn't flipping prove dead too! Left me with singed fingertips and luckily nothing else.