>  For example, ask anybody, an expert or layman, why you can die from
> touching an electrical wall socket (which has at most 230 volts), but
> usually not from an electric cattle fence (which has tens of kilovolts)
> and you won't get a straight, rational answer. I have yet to get a
> proper answer from anybody (which wouldn't seem to violate the basic
> "U=RI" formula).

An electric fence has a very low value current limiter (of the order of a 
few milliamps), whereas you can get 10's of amps from wall sockets.

U=RI is never violated, because a current limiting circuit will control the 
voltage to ensure the current limit is not exceeded.  If you connected a 
voltmeter to the electric fence you would see the voltage drop significantly 
when you touched it.  BTW this is exactly how an LED driver circuit works, 
because they need a constant current supply, rather than voltage.

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