# Why Don't Volts Kill You? **URL:** \ **Category:** Factual Questions\ **Created:** [May 7, 2017, 8:55pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087 "2017-05-07T20:55:11Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Mrdeals](https://avatars.discourse-cdn.com/v4/letter/m/ea666f/32.png) [@Mrdeals](https://boards.straightdope.com/u/Mrdeals)\ **Post date:** [May 7, 2017, 8:55pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/1 "2017-05-07T20:55:11Z")
Question is pretty much exactly as the title reads. I have read that stun guns can pack a punch of over 1,000,000 volts of electricity. However they are not lethal (in 99% of cases) However, it takes very very few amps to kill you. So what is the upper limit of voltage that people can handle? Could i get zapped with a billion volts and come out ok? I thought i heard before too that a person can survive being shocked with 50+ amps, as long as the voltage is extremely small. Am i remembering correctly? ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [May 7, 2017, 9:02pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/2 "2017-05-07T21:02:31Z")
There have been several previous threads, for example: > **[Amps kill you, Volts don't?](https://boards.straightdope.com/sdmb/showthread.php?t=266202)** > > I often hear people say (regarding electrocutions), it’s not the volts that kill you, it’s the amps. This doesn’t really make sense to me. If current and voltage are related by Ohms law ( V = IR ), then shouldn’t you automatically end up with more... > **[Voltage can kill](https://boards.straightdope.com/sdmb/showthread.php?t=368803)** > > My first post!! I am so excited!! I have seen the Mythbuster episode where they showed that 600 Volts from an electrified subway line is enough to kill a person. I also know that it is not the voltage that kills but the current. In this case,... ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [May 7, 2017, 9:13pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/3 "2017-05-07T21:13:09Z")
as usual, attempting to distill a phenomenon down to a trite saying renders it mostly inaccurate. voltage, current and resistance are all interlinked (as shown by Ohm’s law.) The two main ways for a person to be electrocuted are: 1. a current of between 0.1 and 0.2 amps to flow through the heart (e.g. hand-to-hand or hand-to-foot shock.) This can disrupt the heart’s rhythm and send it into ventricular fibrillation, which will not correct itself without a defibrillator, or 2. a current of about 1 amp or greater causing internal burns. in order for either to happen, the shock has to come from a source which has both sufficient voltage to “push” the lethal amounts of current through the resistance of your body, and sufficient current to actually reach those levels. And the resistance of your body depends greatly on whether your skin is dry, wet, sweaty, etc. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 7, 2017, 9:52pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/4 "2017-05-07T21:52:06Z")
Really, it’s not the volts or the amps that kill you. It’s either the hertz or the watts. The “trickle through the heart” method only works with AC, and only of the right frequency (unfortunately, right around the frequency we use for our power grids). And the other method is basically just cooking you, and any other method of dumping the same power into heat would have the same effect. ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [May 7, 2017, 10:04pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/5 "2017-05-07T22:04:54Z")
Think of water pressure. You could have an insanely high pressure…but only a small stream. Like a water-pik toothbrush, not a firehose. The pressure doesn’t knock you off your feet: the combination of pressure and volume does. Voltage is a little like pressure, and amperage is a little like volume. ---
**Author:** ![Weisshund](https://avatars.discourse-cdn.com/v4/letter/w/ba8739/32.png) [@Weisshund](https://boards.straightdope.com/u/Weisshund)\ **Post date:** [May 7, 2017, 10:52pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/6 "2017-05-07T22:52:29Z")
> [@Mrdeals](#): > > I have read that stun guns can pack a punch of over 1,000,000 volts of electricity. However they are not lethal (in 99% of cases) The amperage is very low. To boost up 9vdc to 100,000vdc or more, you sacrifice amps to increase volts Think of it in terms of a garden hose kind of. A very skinny hose might be able to maintain a lot of pressure (volts) But it will have very poor volume of flow (amps) So you aren’t going to drown a guy with it, just sting him and annoy him. Now switch to a very fat hose, while you lose pressure, you do well to drown the guy because you got buckets per second coming out the end. > [@](#): > > However, it takes very very few amps to kill you. Most things you touch have milliamps running through them/you A full amp running directly through you, in respect to your body, it a large amount. > [@](#): > > So what is the upper limit of voltage that people can handle? Could i get zapped with a billion volts and come out ok? I would say a billion volts even at low amps would be very dangerous. Remember the garden hose analogy? Ok figure a garden hose with a tiny output but 12,000 PSI at that little jet. I cant drown you and smash you to pieces, but i can cut you up like it was a laser. > [@](#): > > I thought i heard before too that a person can survive being shocked with 50+ amps, as long as the voltage is extremely small. Am i remembering correctly? I do not think you want to run 50 amps through your body. you can weld light steel together with 50 amps@16vdc ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 8, 2017, 12:14am UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/7 "2017-05-08T00:14:42Z")
You simply can’t change the current and voltage through/across your body independently. If you have a high voltage difference across your body, you _will_ have a high current going through you, and vice-versa. But what you can have is your entire body at the same voltage, even a very high voltage. ---
**Author:** ![Weisshund](https://avatars.discourse-cdn.com/v4/letter/w/ba8739/32.png) [@Weisshund](https://boards.straightdope.com/u/Weisshund)\ **Post date:** [May 8, 2017, 12:25am UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/8 "2017-05-08T00:25:39Z")
> [@Chronos](#): > > You simply can’t change the current and voltage through/across your body independently. If you have a high voltage difference across your body, you _will_ have a high current going through you, and vice-versa. But what you can have is your entire body at the same voltage, even a very high voltage. You mean like when a guy is up on a transmission line, be he isnt connected to earth? He is at high voltage but not using himself as a shunt to ground? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [May 8, 2017, 2:01am UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/9 "2017-05-08T02:01:02Z")
Just a month ago we did this. See [http://boards.straightdope.com/sdmb/showthread.php?t=823421](http://boards.straightdope.com/sdmb/showthread.php?t=823421) for a side discussion on what aspects of what levels of electricity are dangerous and why. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [May 8, 2017, 7:48am UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/10 "2017-05-08T07:48:12Z")
> [@Weisshund](#): > > You mean like when a guy is up on a transmission line, be he isnt connected to earth? > He is at high voltage but not using himself as a shunt to ground? Workers on live systems are connected to the conductor they are working on. They wear a conductive suit that is connected to the power line. This raises their entire body to the voltage of the line. But inside the suit the potential gradient is zero, so they are safe. If the worker were to contact anything at earth potential it would be bad. Probably life threatening burns. This is [probably the best known video](https://www.youtube.com/watch?v=r_1T2_l43Xo) on the subject. The explanation of a Faraday cage is a bit hokey, but you will get the idea. ---
**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:** [May 8, 2017, 10:53am UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/11 "2017-05-08T10:53:40Z")
> [@Chronos](#): > > You simply can’t change the current and voltage through/across your body independently. Exactly. For stun guns you sometimes hear, “The voltage across the body is high, but the current is low.” This is incorrect. It is impossible to design a power source that allows you to dial up any voltage at any current for an arbitrary load. It is one or the other: if you fix the voltage, the current will be freewheeling, and if you fix the current, the voltage will be freewheeling. In the case of stun guns, the initial / open circuit voltage is very high, and the voltage starts decreasing within a few microseconds after the probes make contact with the skin. This is due to the high source impedance of the stun gun. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [May 8, 2017, 1:40pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/12 "2017-05-08T13:40:25Z")
> [@Mrdeals](#): > > I thought i heard before too that a person can survive being shocked with 50+ amps, as long as the voltage is extremely small. Am i remembering correctly? NO. The only way to get 50 amps is to have significant voltage, and therefore significant power, as power = volts \* amps. 50 amps… that would be like 50000 volts… heaps of power. ---
**Author:** ![swampspruce](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/swampspruce/32/261_2.png) [@swampspruce](https://boards.straightdope.com/u/swampspruce)\ **Post date:** [May 8, 2017, 2:44pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/13 "2017-05-08T14:44:19Z")
That’s not true. I work with 100 amp, 2 volt batteries for a solar bank and they have never exceeded 2.5 V peak. They have however arc welded a wrench when inadvertently applied across the terminals… ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [May 8, 2017, 3:00pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/14 "2017-05-08T15:00:51Z")
You missed **Isilder** ’s implied condition that came from **Mrdeals** question: The point was to get 50 amps through a person. Not through a wrench. Given the fairly high impedance/resistance of a (dry) person, getting 50 amps though that circuit is going to take a bunch of volts. Conversely, getting 50 amps through a clean shiny exceedingly low impedance/resistance wrench takes very few volts. As you’ve demonstrated. ---
**Author:** ![Khendrask](https://avatars.discourse-cdn.com/v4/letter/k/3e96dc/32.png) [@Khendrask](https://boards.straightdope.com/u/Khendrask)\ **Post date:** [May 8, 2017, 3:36pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/15 "2017-05-08T15:36:57Z")
There is also the fact that with stun guns, tazers, and the like, the circuit is not completed across the body, but rather across a small section of the body. The current is primarily flowing between the two in-contact electrodes, not from one arm, through the chest and to the other arm. Despite the TV shows, stun-guns cause fairly localized (but extremely intense) pain and burning. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [May 8, 2017, 3:44pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/16 "2017-05-08T15:44:29Z")
> [@Crafter\_Man](#): > > In the case of stun guns, the initial / open circuit voltage is very high, and the voltage starts decreasing within a few microseconds after the probes make contact with the skin. This is due to the high source impedance of the stun gun. The commonly seen Taser fires its darts/probes and then delivers a sequence of electrical shocks via those probes. If I’m understanding your description, then each pulse delivered to the target would be high voltage _and_ high current, but only lasting for a very short period of time (microseconds), with a relatively long (maybe 0.1-0.2 seconds) gap between each pulse. Under these conditions, the time-averaged voltage/current/power delivered to the target is very low (it would have to be, since the Taser’s battery isn’t very big), so thermal injury won’t happen. I suspect the risk to a Taser victim depends heavily on where the darts get attached. If they happen to land in the same place where you would affix AED contact pads (right upper chest + left lower side), my guess is that this would be a worst-case scenario for messing with cardiac function. From [Wikipedia:](https://en.wikipedia.org/wiki/Taser_safety_issues) > [@Wikipedia](#): > > A 2007 study published in The American Journal of Forensic Medicine and Pathology questioned the apparent contradiction created by the claim that the Taser X26 does not stimulate the heart muscle, while clearly causing skeletal muscle contraction and stimulation. They estimated the average current pulse of the X26 at 1 ampere. They concluded that it is primarily proximity (or lack thereof) of the heart to the electrodes that prevents stimulation of the heart, along with the short duration of the pulse, which allows the heart to return to near its baseline state prior to the next pulse, due to the larger time constant for the heart muscle vs skeletal muscles. They estimated a 0.4% chance of heart muscle stimulation among the general population with optimum (or worst case) electrode placement, which would normally resolve itself with the resumption of a normal heart beat. > … > A Chicago study suggests that use of the Taser can interfere with heart function. A team of scientists and doctors at the Cook County hospital trauma center stunned 6 pigs with two 40-second Taser discharges across the chest. Every animal was left with heart rhythm problems and two of the subjects died of cardiac arrest. One of the subjects died three minutes after being shot indicating, according to researcher Bob Walker, that “after the Taser shock ends, there can still be effects that can be evoked and you can still see cardiac effects.” > [@Khendrask](#): > > Despite the TV shows, stun-guns cause fairly localized (but extremely intense) pain and burning. :dubious: You sure about that? It often seems to cause whole-body immobilization. Here for example is [a bull getting tasered,](https://www.youtube.com/watch?v=CearLuAunYg) and he appears to be utterly frozen until the pulses end. ---
**Author:** ![casdave](https://avatars.discourse-cdn.com/v4/letter/c/c6cbf5/32.png) [@casdave](https://boards.straightdope.com/u/casdave)\ **Post date:** [May 8, 2017, 6:31pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/17 "2017-05-08T18:31:23Z")
Its neither the amps nor the volts that harms you its the rate of energy input to the body, often coupled with the location of the energy flow. Electrical energy is just one form of input that can kill, kinetic energy can kill, but again its how quickly that energy is input. For example, a car that pushed you at 1 mph for a few hours, forcing you to keep taking backward steps will not kill, however it that total energy were delivered in maybe a couple of milliseconds, then you are fresh out o it. So it is with electricity, a very small current flow over a long period is not likely to harm you, but the same amount of energy over a few milliseconds will not be good news - This is why it is more accurate to state energy input in joules, or joules per second=Watts. Now you have an idea of the way defibrillators work. ---
**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:** [May 9, 2017, 12:36am UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/18 "2017-05-09T00:36:55Z")
> [@Machine\_Elf](#): > > The commonly seen Taser fires its darts/probes and then delivers a sequence of electrical shocks via those probes. If I’m understanding your description, then each pulse delivered to the target would be high voltage _and_ high current, but only lasting for a very short period of time (microseconds), with a relatively long (maybe 0.1-0.2 seconds) gap between each pulse. Under these conditions, the time-averaged voltage/current/power delivered to the target is very low (it would have to be, since the Taser’s battery isn’t very big), so thermal injury won’t happen. This is somewhat of a WAG, as I can’t find a good schematic of a Taser… Pulsing or not, the Taser produces a high voltage. If you were to connect the probes to a DVM with a very high input impedance, the DVM would read 10,000 V, or 20,000 V, or whatever. This is called the open circuit voltage. The current would be very close to 0. Now… touch the probes to someone’s skin. The voltage will decrease _very_ quickly, probably within a few microseconds. This is because the Taser’s output circuit is high impedance, likely the secondary of a small, HV transformer. And as the voltage rapidly decreases, the current rapidly decreases right along with it. So I _think_ we’re saying the same thing. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [May 9, 2017, 6:38am UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/19 "2017-05-09T06:38:28Z")
[This patent](https://www.google.com/patents/US7602598)pretty well covers the operation, although no schematic. The answer is that 50kV is only to break down the surface resistance of target, and once conduction is achieved the output impedance is about 1kOhm, and the voltage of the pulses drops to about 5kV. None the less, the power delivery is frighteningly large. The M26 is designated so as it delivers 26 watts into the target. ---
**Author:** ![swampspruce](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/swampspruce/32/261_2.png) [@swampspruce](https://boards.straightdope.com/u/swampspruce)\ **Post date:** [May 9, 2017, 7:23pm UTC](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087/20 "2017-05-09T19:23:34Z")
> [@LSLGuy](#): > > You missed **Isilder** ’s implied condition that came from **Mrdeals** question: > > The point was to get 50 amps through a person. Not through a wrench. > > Given the fairly high impedance/resistance of a (dry) person, getting 50 amps though that circuit is going to take a bunch of volts. > > Conversely, getting 50 amps through a clean shiny exceedingly low impedance/resistance wrench takes very few volts. As you’ve demonstrated. The OP was have people survived being zapped by low voltage, high amperage and survived. Yes, they have. Have they survived it being sent across their bodies and through their hearts? That wasn’t the question. FWIW, I was only watching the wrench shower the area with pretty sparks, and the tech with curse words… 🙂 Plenty of folks have “closed the circuit” on car batteries and lived to tell the tale. Running 50 amps **through** your hand is still mucho amperage and low (relative) voltage. To me, that answers the question, and contradicts **Isilder** ’s reply. [Next page](https://boards.straightdope.com/t/why-dont-volts-kill-you/786087.md?page=2)