Originally Posted by
llondel
The biggest danger when near a strike is the ground current as it disperses. The resistance of the earth may mean that two points a metre apart have a 5000V potential difference. This is less of an issue for humans because our feet tend to be a lot closer together, but it takes out a lot of cows if they're in a field and there's a nearby lightning strike.
Correct.
Known in the HV electricity trade as 'step-and-touch' potential. That's why HV substations have a buried earth grid round them. The fault currents, if something goes wrong even on a feeder outside the substation, can be of the order of 10s of kA. And if the earth resistivity is high that can give you a nasty jolt. Just from opening a metal gate or touching the fence. The buried grid evens out voltage differences over a wider area.
Bear in mind any AC voltage above say 65V or so can kill. That's why hand tools should always be fed from a centre-tapped (and earthed) 110V supply. Max 55V to earth. Deemed safe