After reading through Sweeting's paper referenced in IEEE 1584-2018, "Arcing Faults in Electrical Equipment" (2011), I was left puzzled about the section addressing arc-flash impact on the human body. Specifically, he refers to tests conducted on pork legs showing that "[d]ue to the arc's negative v/i characteristic, any arc connection to the body self-extinguishes and is replaced with a glow column." Because of this effect, "resultant voltage across the body is likely to reduce the current across the heart to below ventricular-fibrillation levels." The assertion is that electric shock is not as impactful as burns from arc-flash (I think). My questions are:
(1) What is the negative v/i characteristic - voltage decreases as current increases?
(2) Why does this characteristic cause arcs to self extinguish?
(3) Why does voltage resulting from a glow column take electric shock out of the equation, leaving burns as the primary concern?
Thank you. Link to paper in IEEEXplore:
https://ieeexplore.ieee.org/document/5625907