Why is a.c current more dangerous to humans than d.c at the same voltage,see the Edison, d.c vrs. Tesla a.c debate

We measure AC voltage using the "root mean square" of the AC sinusoidal wave. This is a mathematical technique that determines the average amount of power deliverd by the AC line, and it means the RMS voltage of an AC line is equal to the peak voltage of the sine wave dividede by . Hence the amplitude of the wave form of a 230 volt main AC line is actually about 325 volts. In terms of what's dangerous or not it's this peak voltage that makes a 230 volt RMS AC more dangerous than 230 volt DC, because it's the peak voltage that drives faults like spark-over to ground.