4 ms·

5V to 20V can be fatal?

by ko27 9y ago

lightedman 9y ago
I can kill you with a 12V car battery at 8 amps clamped to your fingers, no problem.
- wlesieutre 9y ago
  No you can't. It has the capacity to deliver 8 amps, but your body's resistance is too high to draw that current. https://www.seattlepi.com/news/article/Car-Talk-Car-battery-can-shock-you-but-it-1203143.php https://www.seattlepi.com/news/article/Car-Talk-Car-battery-... EDIT - here's some math: The U.S. Navy FIRE CONTROLMAN Volumes 01 - 06 & FIREMAN gives 1500 ohms as a common resistance approximation between extremities, either hand to hand or hand to foot, for an average human body. I = V/R = 12V / 1500 Ohms = 0.008 A 8 mA is not nearly enough to kill you.
  - FreeFull 9y ago
    On the other hand, if skin is breached, the resistance is quite a bit smaller, and it won't take too much voltage to cause a deadly current.
    - wlesieutre 9y ago
      There's a story floating around the internet of someone having done by stabbing through their thumbs with a 9V multimeter, and maybe it's possible, but I'm skeptical of the story's veracity. I can see those wacky stories for a lot of situations, but you'd think with somebody dying that there'd be some kind of incident report or other documentation. But sure, it's probably best to not touch the car battery terminals when your hands are bleeding.
    - lightedman 9y ago
      Ding, this person isn't thinking about how sharp those cable clamps are and how strong of a spring it has which can drive that clamp well past the skin. This is how we killed animals on the ranch I grew up on. I know very well what will kill you electrically-speaking.
  - lightedman 9y ago
    You don't know how sharp battery clamps are, do you? They will easily penetrate the skin with those heavy springs and sharp points. At that point, your skin resistance means jack.
- olyjohn 9y ago
  I'm genuinely curious how you'd do that... I can touch both battery terminals with my hands and feel nothing. Even if my hands are damp, nothing happens. My battery is capable of outputting over 700amps.
  - mikeash 9y ago
    People have latched on to the mantra that it’s not the volts that kill you, it’s the amps, but they never seem to remember that you need a certain voltage to get those amps in the first place.
    - planteen 9y ago
      Exactly. And also the mantra "electricity takes the path of least resistance". While that is true, some people seem to interpret it as "electricity only takes the path of least resistance" which is very wrong. Electricity takes all paths!
      - setr 9y ago
        I don't know squat about electricity If electricity takes all paths, then whats the point of the mantra? It includes the highest and least resistance, and everything in between. The mantra is almost deliberately meant to mislead?
        planteen 9y ago
        > If electricity takes all paths, then whats the point of the mantra? It includes the highest and least resistance, and everything in between. The mantra is almost deliberately meant to mislead? Maybe mantra wasn't the right word, Wikipedia calls it a heuristic. Regardless, I agree it is very misleading and I would never say anything like that when teaching or explaining electricity. Why does it keep getting repeated? Who knows. Inertia of the masses without a much understanding of electricity would be my guess... https://en.wikipedia.org/wiki/Path_of_least_resistance https://en.wikipedia.org/wiki/Path_of_least_resistance
        9y ago
- planteen 9y ago
  No way. If that were the case, people would be dying all the time when trying to jump cars. You would need to wear lineman gloves to do it safely and working on cars in general would be quite hazardous. I've touched both car battery terminals before. You don't feel a thing.
triangleman 9y ago
Indirectly, it could start a fire...
boomlinde 9y ago
A 9V battery in the wrong place can kill you.
- munificent 9y ago
  As can a AAA battery, if accelerated sufficiently beforehand.
  - boomlinde 9y ago
    Well, I mean from electrocution specifically. 100-200mA through your heart is probably going to be fatal, and the low resistance required for that to happen with a simple 9V battery source has at least once been achieved by inserting multimeter probes in the thumbs such that the current passed via the blood stream through the heart, causing fibrillation. Interestingly, there exists a sort of upper threshold where the amperage is less likely to be fatal due to severe cramps preventing fibrillation IIRC.
- bshacklett 9y ago
  Would you care to give us a scenario? The best source I could find places the minimum resistance of already damaged human skin at 500 ohms. With 9v of potential, that translates to .018 amps of current, which is just barely above the threshold for sensation, let alone death.
  - boomlinde 9y ago
    0.018 is way above the threshold of sensation, well into the territory of very painful shocks (18 times the threshold of sensation at ~1mA). Of course this will usually be local with a 9V battery, but with some deliberation you can pass the current through your heart via the blood stream, where the resistance is sometimes much lower which can get you very close to what'll likely be fatal. Edit: the above holds true for AC but not necessarily for DC from a battery, where the thresholds are typically higher. But the heart is very sensitive and fibrillation occurs at very low currents passing directly through it.
- beenBoutIT 9y ago

5V to 20V can be fatal?

by ko27 9y ago

5V to 20V can be fatal?

lightedman 9y ago

I can kill you with a 12V car battery at 8 amps clamped to your fingers, no problem.

wlesieutre 9y ago
No you can't. It has the capacity to deliver 8 amps, but your body's resistance is too high to draw that current. https://www.seattlepi.com/news/article/Car-Talk-Car-battery-can-shock-you-but-it-1203143.php https://www.seattlepi.com/news/article/Car-Talk-Car-battery-... EDIT - here's some math: The U.S. Navy FIRE CONTROLMAN Volumes 01 - 06 & FIREMAN gives 1500 ohms as a common resistance approximation between extremities, either hand to hand or hand to foot, for an average human body. I = V/R = 12V / 1500 Ohms = 0.008 A 8 mA is not nearly enough to kill you.
- FreeFull 9y ago
  On the other hand, if skin is breached, the resistance is quite a bit smaller, and it won't take too much voltage to cause a deadly current.
  - wlesieutre 9y ago
    There's a story floating around the internet of someone having done by stabbing through their thumbs with a 9V multimeter, and maybe it's possible, but I'm skeptical of the story's veracity. I can see those wacky stories for a lot of situations, but you'd think with somebody dying that there'd be some kind of incident report or other documentation. But sure, it's probably best to not touch the car battery terminals when your hands are bleeding.
  - lightedman 9y ago
    Ding, this person isn't thinking about how sharp those cable clamps are and how strong of a spring it has which can drive that clamp well past the skin. This is how we killed animals on the ranch I grew up on. I know very well what will kill you electrically-speaking.
- lightedman 9y ago
  You don't know how sharp battery clamps are, do you? They will easily penetrate the skin with those heavy springs and sharp points. At that point, your skin resistance means jack.
olyjohn 9y ago
I'm genuinely curious how you'd do that... I can touch both battery terminals with my hands and feel nothing. Even if my hands are damp, nothing happens. My battery is capable of outputting over 700amps.
- mikeash 9y ago
  People have latched on to the mantra that it’s not the volts that kill you, it’s the amps, but they never seem to remember that you need a certain voltage to get those amps in the first place.
  - planteen 9y ago
    Exactly. And also the mantra "electricity takes the path of least resistance". While that is true, some people seem to interpret it as "electricity only takes the path of least resistance" which is very wrong. Electricity takes all paths!
    - setr 9y ago
      I don't know squat about electricity If electricity takes all paths, then whats the point of the mantra? It includes the highest and least resistance, and everything in between. The mantra is almost deliberately meant to mislead?
      - planteen 9y ago
        > If electricity takes all paths, then whats the point of the mantra? It includes the highest and least resistance, and everything in between. The mantra is almost deliberately meant to mislead? Maybe mantra wasn't the right word, Wikipedia calls it a heuristic. Regardless, I agree it is very misleading and I would never say anything like that when teaching or explaining electricity. Why does it keep getting repeated? Who knows. Inertia of the masses without a much understanding of electricity would be my guess... https://en.wikipedia.org/wiki/Path_of_least_resistance https://en.wikipedia.org/wiki/Path_of_least_resistance
      - 9y ago
planteen 9y ago
No way. If that were the case, people would be dying all the time when trying to jump cars. You would need to wear lineman gloves to do it safely and working on cars in general would be quite hazardous. I've touched both car battery terminals before. You don't feel a thing.

triangleman 9y ago

Indirectly, it could start a fire...

boomlinde 9y ago

A 9V battery in the wrong place can kill you.

munificent 9y ago
As can a AAA battery, if accelerated sufficiently beforehand.
- boomlinde 9y ago
  Well, I mean from electrocution specifically. 100-200mA through your heart is probably going to be fatal, and the low resistance required for that to happen with a simple 9V battery source has at least once been achieved by inserting multimeter probes in the thumbs such that the current passed via the blood stream through the heart, causing fibrillation. Interestingly, there exists a sort of upper threshold where the amperage is less likely to be fatal due to severe cramps preventing fibrillation IIRC.
bshacklett 9y ago
Would you care to give us a scenario? The best source I could find places the minimum resistance of already damaged human skin at 500 ohms. With 9v of potential, that translates to .018 amps of current, which is just barely above the threshold for sensation, let alone death.
- boomlinde 9y ago
  0.018 is way above the threshold of sensation, well into the territory of very painful shocks (18 times the threshold of sensation at ~1mA). Of course this will usually be local with a 9V battery, but with some deliberation you can pass the current through your heart via the blood stream, where the resistance is sometimes much lower which can get you very close to what'll likely be fatal. Edit: the above holds true for AC but not necessarily for DC from a battery, where the thresholds are typically higher. But the heart is very sensitive and fibrillation occurs at very low currents passing directly through it.
beenBoutIT 9y ago