It also depends on the path of current going through your body. If it goes from your left hand and out through your right hand, you more than likely will not die from that, you might smell bad for a while and not have arms, but you can still live. But if the current goes through your heart you typically die. I've seen a guy get electrocuted before. He grabbed onto some conduit that was shorted out. It blew two holes out of his stomach area and he still lived and I've seen a guy get hit and die and there were no visual marks on his body, except for his hand.
Now at 20k volts you will just be a crispy critter!!!!!!!! MikieD, you mentioned DC, the transit system we build usually run on 750 to 800 volts DC and this sh!t will mess you up. I have seen plenty of pictures where damn dope heads and thieves try to steal the copper wire that has 750v DC going threw it. You can usually find them fried about 40 feet away.