I have encountered several articles and posts saying that what electrocute you and cause death is actually not the voltage but the current instead but is not clear to me how this works.
In: Physics
Voltage is a ratio. Using the water analogy of electricity, it’s not the speed water flows, and it’s not quite like pressure, because it doesn’t imply there’s a push or pull behind it. Instead, think of it as a river; and since water flows downhill, think of voltage as the decline, the slope, which can be expressed as a ratio. Water has more propensity to flow down a hill with more slope and regardless how much water is behind it, so it makes for a better analogy than the classic pressure analogy. And when voltage drops, that slope decreases, flattens out.
Amperage is current. The classic analogy kind of works well. How wide is that river? Imagining a cross-section of a larger river, all flowing down a slope is pretty good. Once again, don’t concentrate on the water behind this imaginary cross-section, don’t concentrate on the slope, we’re only talking about the cross-section itself, the area. What makes it terrifying is imagine using your body to stop a garden hose of water. There’s only so much voltage so water is just spilling out the front, and it’s about 3/4″ wide. You get wet. Now imagine using your body to stop the Nile river at the same voltage. Yeah, the water ain’t flowing all that hard, but first we have to flatten you out into a sheet that spans the river, and assuming you were made of plastic and we could do that, what chance do you think you have of stopping or redirecting that current?
It would only take a few milliwatts to kill you. You don’t need a lot of voltage or amperage. What typically saves you is when you get electrocuted, the electrical path THROUGH your body doesn’t bridge your brain or your heart, where it can do some real damage. You don’t need to kill cells by frying them, which would happen because as a human resistor, wattage would be converted into waste heat – the atoms and molecules in your body would act as a load and convert some of that electrical energy and your atoms would get excited – heat. It would be enough to break bonds and disrupt chemical processes. No, you don’t need to kill the cells, you would just need to disrupt vital cellular and bodily functions. Throw your heart into an atithmeia, and you’d die of essentially a heart attack.
So it’s no one thing about electricity that kills you. It’s current, it’s voltage, it’s time – as a high wattage shock over a short time can kill you as some low wattage shocks over a long time.
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