DC cannot cause fibrillation. AC interferes with the heart sinus rhythm which is what makes it so deadly at very low currents.What do you mean by this?
Again the question is about the amount of voltage needed to move a certain amount of current over an already specified resistance. I don't need to soak my hands or puncture my skin. That would give me a different resistance and is not the question. I don't want to know how different resistances or amounts of current affect me. The question is how different voltages affect the amount of current I would receive with my specified resistance. Actually, I already know how they should affect me the question was about the mathematical assumptions made.
It seems the biggest factor I overlooked is how the capacitance of the body blocks to an extent DC current.
DC can cause a great deal of pain but doesn’t kill you unless it cooks you (over 10 A). But it causes involuntary contraction of muscles at milliamperes of current. The contraction is the pain source and when it stops the reaction from the muscles can be so violent it can break bones.
Back in the 1950s we really didn’t know anything about the effects of electricity. Charles Dalzeil was the first to study it. There is a set of 4 technical papers on the subject that he published that are freely available. Since that time some refinements have been made but the basic concepts established by Dalzeil still hold true.
Among those concepts Dalzeil established that clinical effects are related to body weight and current, not voltage. Voltage is strongly affected by skin resistance. Internal resistance is affected mostly by body weight and is almost universal even among different mammals. So for instance the thresholds tend to be lower in human females due to smaller body weight. This is fortunate as it allowed him to do lethal testing on rabbits instead of humans.
Dalzeil did some experiments on skin and found resistance varied widely but that a lower threshold was about 1 K ohms but dry skin could be quite a bit higher, Voltage matters too but you may not be interested in “Meggering” yourself. I know I really don’t like doing it accidentally. IEC published details on the effect of voltage on skin resistance. So the results you get at 9 V with a multimeter will be significantly higher than at 100+ V where it matters.
If you are getting to voltage thresholds it is generally held that 50 VAC is safe. I have read somewhere that an extreme situation of a man with a pace maker pinned so he could not escape was killed by under 50 VAC in an MSHA area (mining) but even they admitted this was an outlier. Roberts (Canadian) did some questionable math with the IEC standard and came up with 28 VAC as a threshold and justified it by some essentially unverifiable reports of incidents in China. Based on preponderance of evidence I’m not buying any of it. For DC no similar equivalent exists. 70E did use AC=DC for a while and was widely criticized for it. The proposals mostly recommended around 150 VDC as a minimum safe limit.
I have personally experienced shocks at 1400 VAC and had coworkers that have taken up to a 4160 V (7200 V L-L) shock and lived to tell about it and I’ve known of cases even higher. It is fatal depending on the path it travels through the body (hand to hand being the worst) and as you’ve found out skin resistance. The fact that the sensation and pain thresholds are a lot lower than fatal shocks and given that many people have experienced much higher voltages and lived through it tells you that fatal shocks are not that common. But when it does happen you have minutes to address the heart afibrillation that occurs. An AED can in most cases recover normal rhythm. In my AED training it’s around 80% success. Fortunately I have not had an “opportunity” to test this on either myself or others. But on a couple incidents involving “Megger” testing where residual polarization has accidentally hit me pretty hard I have experienced DC involuntary muscle contractions first hand. I do a lot of MV work where those tests are 1000-10,000 V.
So not sure what you are after but don’t expect safety-thresholds meant for worst case to correspond to average situations and don’t expect fatal conditions just because of a one time incident with say 120 V. It only takes once but no lethal shocks are a lot more common than most electricians admit to.