# How many volts and amps does it take to kill a human? **URL:** \ **Category:** Factual Questions\ **Created:** [October 22, 2015, 4:36pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469 "2015-10-22T16:36:47Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![KaleMan](https://avatars.discourse-cdn.com/v4/letter/k/3bc359/32.png) [@KaleMan](https://boards.straightdope.com/u/KaleMan)\ **Post date:** [October 22, 2015, 8:26pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/21 "2015-10-22T20:26:09Z")
> [@Marvin\_the\_Martian](#): > > OK, here’s a link which gives a decent explanation: > > [https://www.physics.ohio-state.edu/~p616/safety/fatal\_current.html](https://www.physics.ohio-state.edu/~p616/safety/fatal_current.html) > > Interestingly, there is a “sweet spot” between 100-200mA which is enough current to produce ventricular fibrillation and certain death (unless you have a defibrillator, and someone to use it, handy). Over 200mA the heart muscle “clamps” and won’t go into fibrillation, but your breathing has likely stopped with predictable results in the absence of CPR. > > Regarding the question of the resistance of the heart: I found a paper which has measurements of the resistance of a dogs heart ([The Electrical Resistance of the Heart - PMC](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1802529/)) which gives an average of 50 ohms. Assuming a human heart has a resistance _on the order of_ 100 ohms, then a voltage _on the order of_ 10 volts applied directly across the heart will produce a current on the order of 100 mA. > > What saves you in real life is your skin resistance, which can range from around 1 kohm for wet skin to hundreds of kohm for dry (see the “Fatal Current” citation above). Now I get it 🙂 my dry skin safe me ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [October 22, 2015, 8:33pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/22 "2015-10-22T20:33:31Z")
> [@KaleMan](#): > > Now I get it 🙂 my dry skin safe me But sweat just a little and you’re toast… ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 22, 2015, 9:01pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/23 "2015-10-22T21:01:42Z")
Electricity tends to kill you in two different ways. The first way is that it screws up your heartbeat. Hit the heart with a shock at just the right time, and it will go into fibrillation, where it just sits there and shakes and isn’t pumping blood. Our heart has kind of a funny design in that this fibrillation state is stable, meaning that the heart generally won’t go out of fibrillation on its own once you get it there. Since the heart isn’t pumping blood, you pass out in a few seconds (maybe 10 to 15 seconds tops) and then die a few minutes later. Better hope there is someone nearby with a portable defibrillator. It takes a surprisingly small amount of current to throw the heart into fibrillation. Electrical standards in the U.S. are generally based around currents under 5 mA being “safe”, though not a lot of human testing has been done to confirm this for ethical reasons that I hope should be obvious. The numbers are based more on animal studies than human guinea pigs. Even though a 5 mA current can theoretically kill you, it’s not very likely to. As the current increases, so does the risk of fibrillation, up until you get around the 50 to 100 mA range mentioned upthread, at which point the risk of fibrillation is much more severe. Fibrillation is kinda hit and miss though. Your heart is much more sensitive to disruptions at certain times during its cycle than others, so there’s a lot of luck involved with the timing of exactly when the shock hits your heart. A funny thing happens as you increase the current though. At higher current levels, the heart doesn’t go into fibrillation. Instead, all of the heart muscles just clamp. At that point the heart isn’t pumping blood, so again you will pass out and die if the source of the current isn’t removed. However, once the current is removed, the heart generally goes back into a normal rhythm. As you keep increasing the current, you start getting into the second way that electricity kills you. It literally cooks you to death. This is how the electric chair kills you. It’s also how lightning usually kills you. There’s a wicked amount of energy in a lightning bolt - hundreds of millions of volts and hundreds of thousands of amps. At those extremes, lightning becomes very weird and unpredictable. The electric chair is pretty much always fatal, and that’s only a few thousand volts (over a much longer duration). Lightning, even with its bizarrely high voltages and currents, will sometimes fry you to a crisp and will sometimes leave you relatively unscathed. So overall, what happens is that as you increase the current (generally by increasing the voltage), the fatality rate starts off near zero, the rises, then drops for a bit as you get into the range of the heart clamping, then rises again as you get into heat damage. > [@Ex\_Bubblehead](#): > > Total power has nothing to do with it, it’s the current, and 100-200ma across the heart is lethal no matter the voltage or total power. While it is true that it’s the current that matters in this case, voltage and current aren’t exactly unrelated. All other things being equal, a larger voltage will result in a larger current. All other things are not always equal though. > [@PastTense](#): > > So what is the resistance across the heart? You’re not going to get 100-200 ma at low voltages. The “resistance” of the human body varies. Humans aren’t simple ohmic resistors. A commonly used model of the human body is a resistor in series with a resistor and capacitor in parallel, but the values of those components varies depending on the circumstances. At low voltages, the “resistance” will be several k to several megs. At higher voltages, the “resistance” of the body drops to somewhere around 500 to 1000 ohms, which is a pretty significant difference. I’ve heard about someone killing themselves with low voltages (like 3 to 6 volts from batteries, somewhere in that range) by using something that stuck needles or probes into their skin. It might just be an electrical urban legend though as I’ve never been able to confirm it. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 22, 2015, 9:06pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/24 "2015-10-22T21:06:40Z")
> [@KaleMan](#): > > Okay you mean two AAA batteries from your TV remote control can kill you??? It could, but you’d probably need to have the electrical contacts pierce your skin to overcome your skin’s resistance. Generally speaking, you need to get somewhere in the range of 50 volts or so before the voltage will overcome your skin’s resistance and the resulting current starts to get dangerous. ---
**Author:** ![Atamasama](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/atamasama/32/12961_2.png) [@Atamasama](https://boards.straightdope.com/u/Atamasama)\ **Post date:** [October 22, 2015, 9:07pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/25 "2015-10-22T21:07:52Z")
Skin resistance may save your heart but you’ll probably sustain very bad burns. Though I’d take that over cardiac arrest. ---
**Author:** ![usedtobe](https://avatars.discourse-cdn.com/v4/letter/u/ec9cab/32.png) [@usedtobe](https://boards.straightdope.com/u/usedtobe)\ **Post date:** [October 23, 2015, 5:12am UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/26 "2015-10-23T05:12:51Z")
There is an ancient (no cite) story of a US Navy recruit in training to be an Electrician. One day, they were issued volt/ammeters and had a discussion about safety, including the fact that human skin was actually a pretty decent insulator. At this point, for those who don’t know - the instrument has a small battery used to place voltage across a circuit to measure resistance. This is the set-up. Pondering the question of skin and resistance, the story goes, he poked small holes in his index fingers, and placed the leads in the holes to measure the resistance of human meat. The voltage (from a tiny battery, 9v ‘transistor’ batteries, for instance) passed through his heart. As mentioned above, it takes virtually no current to stop a heart - esp. when those are pure DC (as from batteries). My Q: anyone have a cite for this story of volt meter killing an inquisitive Electrical student in the USN? ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [October 23, 2015, 2:19pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/27 "2015-10-23T14:19:40Z")
> [@Ex\_Bubblehead](#): > > 100ma across the heart is lethal. Doesn’t matter how many volts it takes to get there. Yep. And it is not possible (at least right now) to calculate how many volts is necessary to achieve 100 mA or whatever. In order to determine the voltage necessary to achieve a certain current through the body, we would need an accurate electrical model of the human body. Such a model does not exist at this time. The human body cannot be modeled as a simple resistor. Or a resistor & capacitor. Furthermore, the current in the human body is not due to mobile electrons but _mobile ions_. Scientists have spent the last hundred years studying the electrical impedance of saltwater in the lab, and they _still_ don’t have a good handle on it. So when it comes to voltage and the human body, about the best you can do is go by some rules-of-thumb. **ECG** brought up one: voltages less than 50 V are \*generally \*considered safe, for \*most \*people, in \*most \*circumstances, \*most \*of the time. 🙂 ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [October 23, 2015, 2:48pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/28 "2015-10-23T14:48:31Z")
> [@Ex\_Bubblehead](#): > > Total power has nothing to do with it, it’s the current, and 100-200ma across the heart is lethal no matter the voltage or total power. _Through_, not across! Voltage is across, current is through. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [October 23, 2015, 3:04pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/29 "2015-10-23T15:04:20Z")
Remember that a sharp blow to the chest at just the right spot and the right time can stop the heart, but it’s a rare occurrence. I’m sure most electrocutions involve higher voltages and currents, and probably AC. There have been plenty of electricians who tested for hot wires by touching them, and a friend of mine who works for National Grid on the heavy power lines says he doesn’t even care about household electricity because even 240 volts isn’t going to kill him. I’d be a little more cautious myself, but it’s an indication of how rare electrocutions are under normal circumstances. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [October 23, 2015, 3:29pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/30 "2015-10-23T15:29:13Z")
The large capacitor has enough energy to electrocute by affecting the heart electrochemistry… It also has enough energy to cause painful burns to the skin, and cramp up your biceps and other muscles… This cramping can then have serious results… eg disabling injury to muscles… tear something (muscle,ligament, joint tissues, break a bone ), pinch a nerve, wry neck… Worse, if you are working near exposed mains power, you might then be touching mains power… repeat for other dangers (even the floor is a danger… if you fall over and bang your head on it… falling over rotating fast enough to hit head first… ) ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 23, 2015, 3:38pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/31 "2015-10-23T15:38:45Z")
> [@usedtobe](#): > > My Q: anyone have a cite for this story of volt meter killing an inquisitive Electrical student in the USN? This is basically what I was referring to in the last line of my post #23 above. I’ve heard several variants on this story. The most common is that it was an electrical technician of some sort, sometimes in the USN, sometimes not. The other variant that I’ve heard was that it was some sort of device used for sexual pleasure, and not a meter. The key in every version though is that the skin was somehow punctured in order to overcome the skin’s resistance. I’ve never been able to confirm any version of this story, which is why I’m wondering if this is an electrical urban legend. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 23, 2015, 3:42pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/32 "2015-10-23T15:42:23Z")
This is the USN version, commonly known because it has been passed around as a Darwin award. > [@](#): > > (1999) A US Navy safety publication describes injuries incurred while doing don’t’s. One page described the fate of a sailor playing with a multimeter in an unauthorized manner. He was curious about the resistance level of the human body. He had a Simpson 260 multimeter, a small unit powered by a 9-volt battery. That may not seem powerful enough to be dangerous… but it can be deadly in the wrong hands. > > The sailor took a probe in each hand to measure his bodily resistance from thumb to thumb. But the probes had sharp tips, and in his excitement he pressed his thumbs hard enough against the probes to break the skin. Once the salty conducting fluid known as blood was available, the current from the multimeter travelled right across the sailor’s heart, disrupting the electrical regulation of his heartbeat. He died before he could record his Ohms. > > The lesson? The Navy issues very few objects which are designed to be stuck into the human body. From here: [1999 Darwin Award: Resistance is Futile](http://www.darwinawards.com/darwin/darwin1999-50.html) Note that the Darwin Awards page lists it as “unconfirmed”. ---
**Author:** ![Atamasama](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/atamasama/32/12961_2.png) [@Atamasama](https://boards.straightdope.com/u/Atamasama)\ **Post date:** [October 23, 2015, 4:48pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/33 "2015-10-23T16:48:01Z")
Darwin Awards, aka “funny stories people made up”. ---
**Author:** ![KaleMan](https://avatars.discourse-cdn.com/v4/letter/k/3bc359/32.png) [@KaleMan](https://boards.straightdope.com/u/KaleMan)\ **Post date:** [October 26, 2015, 6:34pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/34 "2015-10-26T18:34:33Z")
> [@engineer\_comp\_geek](#): > > It could, but you’d probably need to have the electrical contacts pierce your skin to overcome your skin’s resistance. Generally speaking, you need to get somewhere in the range of 50 volts or so before the voltage will overcome your skin’s resistance and the resulting current starts to get dangerous. how people can survive after million volts go through the body > **[Roy Sullivan](https://en.wikipedia.org/wiki/Roy_Sullivan)** > > Roy Cleveland Sullivan (February 7, 1912 – September 28, 1983) was an American park ranger in Shenandoah National Park in Virginia. Between 1942 and 1977, Sullivan was claimed to have been struck by lightning on seven occasions, surviving all of them. For this reason, he gained the nicknames "Human Lightning Conductor" and "Human Lightning Rod". Sullivan is recognized by Guinness World Records as the person struck by lightning more recorded times than any other human being. > Roy was born in ... ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [October 26, 2015, 6:44pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/35 "2015-10-26T18:44:08Z")
> [@KaleMan](#): > > how people can survive after million volts go through the body > > [Roy Sullivan - Wikipedia](https://en.wikipedia.org/wiki/Roy_Sullivan) People survive getting shot, too. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [October 26, 2015, 6:56pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/36 "2015-10-26T18:56:47Z")
> [@Crafter\_Man](#): > > Yep. And it is not possible (at least right now) to calculate how many volts is necessary to achieve 100 mA or whatever. > > In order to determine the voltage necessary to achieve a certain current through the body, we would need an accurate electrical model of the human body. Such a model does not exist at this time. > > The human body cannot be modeled as a simple resistor. Or a resistor & capacitor. Furthermore, the current in the human body is not due to mobile electrons but _mobile ions_. Scientists have spent the last hundred years studying the electrical impedance of saltwater in the lab, and they _still_ don’t have a good handle on it. > > So when it comes to voltage and the human body, about the best you can do is go by some rules-of-thumb. **ECG** brought up one: voltages less than 50 V are \*generally \*considered safe, for \*most \*people, in \*most \*circumstances, \*most \*of the time. 🙂 Were you part of this thread? Your input would be perfectly on point (and an excuse to zombifie it is always welcome): **How many people connected in series to power a lightbulb?** This sounds like the beginning of a joke, but, given GQ standards, it’s deadly serious. There’s a sole 60-watt light bulb that must be turned on for a minute or everyone will die of fear of darkness. You have insertable single head-plugs, luckily made of lithium, and you have a ton of connection wire. The head of each plug is 2 centimeters in radius. You decide everyone must chip in and give their electroconductive best, and be plugged in in series to generate their share of amps. How many people would be needed to save the day? > **[How many people connected in series to power a lightbulb?](https://boards.straightdope.com/sdmb/showthread.php?t=553857)** > > This sounds like the beginning of a joke, but, given GQ standards, it’s deadly serious. There’s a sole 60-watt light bulb that must be turned on for a minute or everyone will die of fear of darkness. You have insertable single head-plugs, luckily... ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [October 26, 2015, 7:04pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/37 "2015-10-26T19:04:49Z")
> [@jz78817](#): > > you need sufficient voltage to “push” the lethal amount of current through your heart. that could be as low as a couple of volts (like from your AAA batteries) if done through electrodes embedded in your chest, to hundreds of volts if applied hand-to-foot through dry skin. As with anything, the resistance of the circuit is key. there’s a reason it’s “Ohm’s **law** ” and not “Ohm’s general observations.” It should really be Ohm’s general observation. Most complex things like say biological tissue do not obey Ohm’s law very closely. It is a lot like Hook’s law springs only Obey Hook’s law over a smallish range. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [October 26, 2015, 7:06pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/38 "2015-10-26T19:06:23Z")
> [@](#): > > \*\*How many volts and amps does it take to kill a human? \*\* Rare, medium-rare, medium, or well done? * * * My father had an old anecdote about a college prof who used to charge up a Leyden jar (those were the days) and demonstrate resistance in series by having the students stand in a circle holding hands and he and the other end of the circle would touch the opposite contacts of the jar, and everyone would feel a slight tingle. Then to demonstrate the RC constant effect, he would drain the remaining charge by holding the one contact with his finger and touching the other contact close to his nose for a small visible spark. One clever student heard about this demonstration beforehand and persuaded the fellow next to him not to hold hands… Then, after the RC demonstration, when the prof regained consciousness… ---
**Author:** ![KaleMan](https://avatars.discourse-cdn.com/v4/letter/k/3bc359/32.png) [@KaleMan](https://boards.straightdope.com/u/KaleMan)\ **Post date:** [October 29, 2015, 1:55pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/39 "2015-10-29T13:55:47Z")
> [@beowulff](#): > > People survive getting shot, too. seven times in head? ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [October 29, 2015, 4:44pm UTC](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469/40 "2015-10-29T16:44:55Z")
> [@beowulff](#): > > People survive getting shot, too. > [@KaleMan](#): > > seven times in head? …pausing only once to reload… [Previous page](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469.md?page=1) [Next page](https://boards.straightdope.com/t/how-many-volts-and-amps-does-it-take-to-kill-a-human/735469.md?page=3)