Here's the kicker.
A. Albert Biss, P.E., in his 2/28/92 CPSC Technical Report on GFCI states that the average adult male cannot let go when current reaches 16 mA. Currents above 18 mA, when flowing cross-body, cause the chest muscles to contract resulting in suffocation.
Applying Ohm's Law: 120 V รท 0.016 A = 7500 Ohms . . . that's 7.5 K.
