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I was reading an article from abcnews about Why so many people survive being struck by lightning. Later in the article it says the following:

But direct strikes make up only a minuscule portion of all lightning strikes, said Cooper.

"The vast majority of deaths are caused by ground current, where lightning hits a distance away and then travels through the ground in all directions. And if you're close enough to the point it hit the ground, then you get an electric charge," Cooper added.

I understand that rubber shoes might not provide protection against direct lightning strikes. However would shoes with rubber soles provide any form of protection against cloud-to-ground lightning strikes (where the electrical current goes through the ground)?

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    $\begingroup$ I haven't tried that but according to me it would do more damage than to protect. Since if by any chance lightning strikes you , the rubber shoes will provide more resistance causing extreme heat. $\endgroup$ – Jdeep Jul 19 '20 at 12:16
  • $\begingroup$ @NoahJ.Standerson The current would not take a path providing high resistance(unless it is forced to do so). Hence wearing rubber shoes would actually reduce the risk of getting a shock. $\endgroup$ – user243016 Jul 19 '20 at 12:51
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    $\begingroup$ My first thought is it is the right direction, but not enough. Something like putting on a coat will as protection against bullets. $\endgroup$ – mmesser314 Jul 19 '20 at 13:31
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    $\begingroup$ It's worth pointing out that Cooper says a vast majority of deaths occur when lightning hits the ground and the current travels to the person. Pretty much all shoes have rubber soles. Odds are high during a lightning storm if you're struck that you'll be outside. Given that, there's good odds you're wearing shoes. So it doesn't seem like the shoes are providing much protection. And that makes sense. At voltages that high, there's not much that doesn't look like a conductor $\endgroup$ – Jim Aug 4 '20 at 13:46
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    $\begingroup$ Also note, If you're standing outside in a thunder storm, then it's very likely that your shoes are wet. $\endgroup$ – Solomon Slow Aug 4 '20 at 17:02
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Yes, rubber shoes would reduce the amount of current that flows through your body. Here's a rough model for ground-splash: Assume the ground is flat and of uniform conductivity. With no one standing on it, lightning that hits the ground will produce a voltage on the ground $V(r)$ which depends only on the distance from the location of the strike. Wet ground is typically pretty conductive, so let's assume that the amount of current flowing through the dirt is much greater than any amount of current that might flow through your body. We can then add a human to the situation without changing the potential field much. We can model the human as a resistor of resistance $R$ with feet at locations $r_1$, $r_2$. The current that flows through you is then $$I = \frac{|V(r_1) - V(r_2)|}{R}$$ and the total power dissipated in your body and shoes is $$ I^2R = \frac{(V(r_1) - V(r_2))^2}{R}$$ Rubber shoes increase $R$, so they decrease the amount of current you carry and the amount of energy you dissipate. (Also, energy dissipated in your shoes is probably less harmful than energy dissipated in your torso). This model also demonstrates another very important lightning safety tip: Keep your feet together.

Other answers seem to assume the amount of current you carry is fixed. This might be approximately true for a direct strike, but is probably not true for ground splash. If your body has very low resistance or the soil has very high resistance, I think we can model the situation as a current divider to see that the rubber shoes still help.

Exercise for the reader: How does the resistance of your body compare to that of the dirt between your feet? Helpful links: https://en.wikipedia.org/wiki/Soil_resistivity https://pubmed.ncbi.nlm.nih.gov/10593226/

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  • $\begingroup$ What's the breakdown voltage per unit length for typical rubber? A ~1 MV and ~10 kA kind of ruin linear circuit assumptions since most things look like conductors at those high values. Perhaps I am over complicating it but this answer seems overly simplified. Further, it's difficult to imagine a dry lightning strike, which means most of your feet will be wet offering alternative pathways to your body for the current than through the rubber sole. $\endgroup$ – honeste_vivere Aug 5 '20 at 15:11
  • $\begingroup$ The simple model uses linear circuit assumptions, but I don't think the conclusion actually depends on them. The model is "over simplified" in that it does not accurately capture the magnitude of the effect, but I think it does accurately capture the direction - shoes are always less conductive than no shoes, and wet shoes are probably less conductive than wet feet. Unless you're worried rubber might have negative differential resistance somewhere? $\endgroup$ – Daniel Aug 5 '20 at 16:37
  • $\begingroup$ It's more that at those currents and voltages, the difference between your foot and rubber is negligible, I think. Once breakdown occurs, it might as well be a conductor... $\endgroup$ – honeste_vivere Aug 5 '20 at 18:31
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    $\begingroup$ Ground splash is more commonly experienced at larger $r$, since that's most of the surface area. The fields involved are not nearly as large as those near the strike. Currents under 1A can still be quite dangerous to humans, so there is a large range of $r$-values in which ground splash could be dangerous, but the rubber soles would not break down. It seems plausible that rubber shoes are much less helpful neaerr the location of the strike. $\endgroup$ – Daniel Aug 5 '20 at 19:38

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