The human body has roughly 25 ohm's of resistance and heart beat pulses at 60hz. So the path to ground needs to be less, so current choose's the least resistant path to ground in the event of contacting live parts. try checking resistance on yourself, you will see a many different reading
s as you place probes at different locations on yourself. OH and DSA (department of state architect's) does a earth ground test every time I install rods on high school campus electrical systems.If 25 or less is not achieved, I must correct, either by soil treament or driving another rod no more than 6 feet from first.