When I was in the Navy, they used to tell us that the body's resistance could, under certain circumstances, be as low as 300 ohms. If you apply Ohm's Law, you will find that 30 volts can push .1 amp through your body, and put you in a pine box. It's not likely to happen, but those Navy instructor's got their info from somewhere. Do you think that it happened on some submarine? The old ones were DC. Thought I would throw in my 2 cents.
I=E/R,
Doc