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A solar power book makes this claim:

A low voltage system can cause major problems simply because of the huge current that a 12v battery can generate: in excess of 1,000 amps in short burst can easily cause a severe shock -- and even death of serious injury in some cases.

(It goes on to say that a 12v battery can also cause a fire in the case of a short, something I think is undisputable.)

I've heard of these alleged deaths from 12V batteries before, but I can't recall the source right now. The aforementioned book is something I found in 3s on google. Here is another one:

If you have wet, salty hands and grab hold of the terminals of a 12 Volt battery, there is a significant danger of severe shock or even death in certain cases.

Anyhow, my question is: where's the evidence? I'd like to see some case reports (even if just in the mass media) that exemplify this death by electroshock from 12v battery.

Also, let's exclude ingesting batteries, because then even 3V can kill you (and probably 1.5V as well, but I can't a find a case right now) through internal hemorrhaging etc. caused by the electrical discharge burning tissue. The usual context of the claims about (high-amperage) 12v batteries (car, solar power etc.) typically precludes the swallowing scenario.

Fizz
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  • It is the current that kills you.This question should be in physics or electricals. – Grasper Oct 31 '17 at 11:53
  • @Grasper: it's not a theory question. It's one about actual occurrences of events. – Fizz Oct 31 '17 at 12:17
  • @Grasper I'd argue it's more biology than physics or electronics. Generally physicists aren't concerned with how lethal things like this are. Regardless, it may be "the current that kills you", but it's definitely possible to estimate the resistance of a person and therefore determine the expected current given an applied voltage. – JMac Oct 31 '17 at 12:28
  • https://electronics.stackexchange.com/questions/9222/safe-current-limit-for-human-contact possibly related (also suggests differently than the claims here). – JMac Oct 31 '17 at 12:28
  • @JMac: I note there the following comment: https://electronics.stackexchange.com/questions/9222/safe-current-limit-for-human-contact#comment33308_9244 – Fizz Oct 31 '17 at 12:59
  • It's not the current that kills you, it's your heart stopping, or the burns, or the fall from being unconscious. The voltage has to be high enough to do its thing depending on your situation, meaning it needs to cross your heart or arc onto you. – daniel Oct 31 '17 at 16:57
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    Very much related: [How much voltage is “dangerous”?](https://electronics.stackexchange.com/q/19103/5830) on [electronics.se]. – user Nov 01 '17 at 09:08
  • 3V death: I don't have access to the full text but the abstract says the cause of death was a fistula from aorta to esophagus - the kid basically bled to death. This review https://www.ncbi.nlm.nih.gov/pubmed/15221361 gives 4 mechanisms for esophagus damage by ingested batteries. None of them is electric shock: toxicity e.g. due to mercury oxide, electric discharge causing mucosal burn (note that the discharge electrolyses water producing acid [cmp. acidic taste when licking 4.5 V or 9V block batteries] which causes burns), necrosis from pressure of the foreign body, alkali burn from leakage. – cbeleites unhappy with SX Nov 01 '17 at 20:53
  • @anonymized: you are correct, none of the mechanisms of damage (or death) from swallowing coin batteries is fibrillation. Nevertheless the main cause of rapid damage is the electrical discharge of the battery burning tissue within hours sometimes with fatal consequences (which themselves may be delayed). According to Wikipedia's article on electric shock (which cites a plausible source for this definition) "Electric shock is often used to describe an injurious exposure to electricity"; so coin cells seemed worth mentioning, even though the papers coin cell deaths avoid using "electric shock". – Fizz Nov 02 '17 at 03:24

2 Answers2

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No, you can't get an electric shock from a 12V power source.

The Underwrites Laboratory which regulates product safety in the US defines "hazardous voltage" as

Hazardous Voltage Any voltage exceeding 42.2 Vac peak or 60 Vdc without a limited current circuit

http://www.cui.com/catalog/resource/power-supply-safety-standards-agencies-and-marks.pdf.

Anything below this is considered Extra Low Voltage and product designers are not required to provide any type of access protection for the user. That why it is perfectly legal to have batteries with exposed contacts.

Interaction between electricity and the human body is quite complicated (See for example https://en.wikipedia.org/wiki/Electric_shock) but in general the main factors are amount of current and time of exposure. Given the electrical resistance of the human body, 12V are simply not enough voltage to drive significant current through a human. In fact, in almost all cases you won't feel anything at all.

You could potentially construct scenarios where it becomes a very noticeable effect: e.g. bring the the terminal close together and stick your tongue in there. This may fit someone's definition of a shock.

This being said: Big Batteries or solar sources contain a lot of energy and are quite dangerous if being abused.

It's entirely possible to make them over heat, create a fire, explode, cause severe burns, acid damage & burns, mechanical body damage etc. They should be treated with respect and care. There are significant dangers if mishandled, but electric shock is not one of them.

Hilmar
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  • Extra low voltage was taught to me as 24V DC, wet or broken skin would allow shocks and maybe death at lower voltages. – daniel Oct 31 '17 at 17:00
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    Note that there are rare cases where this can go out the window: low-impedance connections like medical jelled electrodes or skin penetration, if coupled with pre-existing ticker timing issues can vastly change the voltages required. – 0xDBFB7 Nov 01 '17 at 02:31
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    An accurate method of determining danger is to use the energy delivered to the body. The typical standard threshold is, IIRC, 100 mJ. A millisecond 10kv pulse to the heart, as in tasers, delivers very little energy, for instance, where such a pulse would typically break both the voltage and current limits. – 0xDBFB7 Nov 01 '17 at 02:34
  • "terminal close together and stick your tongue in there" to put this into some experimental context: as kids we used to check whether 4.5 V flat block batteries were still OK by this licking test. 9 V block batteries were "who dares licking" 12 V batteries were too large to conveniently lick both poles (and that's dangerous because the poles are made of lead) ;-) But anyways, shorting 12 V over the tongue, the current will not be anywhere where it could cause irregular heart beat or a fall or unconsciusness. – cbeleites unhappy with SX Nov 01 '17 at 20:31
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    This answer from electrical engineering seems to disagree with you: https://electronics.stackexchange.com/a/19120/101831 Whether you believe the theorizing / anecdotes in that answer or not, the first line of your answer should probably changed to say that 12 V can't deliver a *lethal*, electrical shock, because 12V can definitely give you a non-lethal shock. – eirikdaude Nov 02 '17 at 09:56
  • @eirikdaude: Thanks for finding that. I think that's where I read it first. But after looking at the [1998 NIOSH report](https://www.cdc.gov/niosh/docs/98-131/pdfs/98-131.pdf), only one death was even due to DC (out of ~200); p. 15. They don't mention any death below 110V (p. 17), which I do find a little strange though because I did find media reports of people killed by welding machines; I guess after investigation it turned out most/all of these were/are from the primary/mains. – Fizz Nov 03 '17 at 00:41
  • @anonymized Shorting a 9V with your tongue creates a current through your tongue. The size of that current is irrelevant to the heart beat, because it is not through the heart. – Acccumulation Nov 03 '17 at 02:58
  • @ Giskard42 The issue with electrodes is not just low impedance, but location. If you touch opposite terminals of a battery with opposite hands, then the current has to flow through your arms to get to your chest. Since your arms are long and thin, the resistance is high. If you have electrodes on your chest, the current has very little distance to travel to get to your heart. – Acccumulation Nov 03 '17 at 03:03
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    @Acccumulation: I just took a 9V battery, made the contacts nice and wet and pressed them against my chest in the heart area. I'm happy to report that A) I am still alive and B) I didn't feel anything at all. I've worked a lot with power electronics and got my fair share of unpleasant encounters, however 12V or 9V are simply not in this class. Disclaimer: I'm a trained and degreed professional, don't fuzz around with electronics unless you know what you are doing – Hilmar Nov 04 '17 at 16:20
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    @Hilmar I just said that proximity is a factor. I never said it is the sole factor. – Acccumulation Nov 04 '17 at 20:17
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    @Hilmar - That's a lousy test. The close proximity of the two terminals would have short-circuited any current that passed through the skin, and virtually nothing would have passed through the 2-3 inches to the heart. – Daniel R Hicks Dec 11 '19 at 13:03
  • @eirikdaude The answer from electrical engineering seems to say you can get an electric shock if you are standing in salt water (up to the knee, let's guesstimate) and complete a circuit through yourself and the water. It certainly sounds plausible since the water provides a very large contact area (compared to touching a wire). However, I think that's a sufficiently specific situation that a *broad generalization* as "no, you can't" is reasonable. For safety though, it should be "no, you can't unless you try really hard." – user253751 Dec 13 '19 at 13:31
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Yes with wet hands and a spanner and a gold ring and a cut, thoroughly setting things up, or by chewing the terminals, rarely some people shock themselves from 12v, although it is nearly impossible and i doubt deaths have occured. https://community.cartalk.com/t/help-please-electrical-shock-from-battery/65722

bandybabboon
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    Can you provide a source demonstrating that this has happened? – F1Krazy Dec 11 '19 at 07:07
  • Garagists that cut themselves on a plus terminal while simultaneously grounded to the car frame or something. Some freak circumstances...https://community.cartalk.com/t/help-please-electrical-shock-from-battery/65722 – bandybabboon Dec 11 '19 at 10:01
  • Could you edit that link (and the relevant information from it) into your answer? That ought to be enough to fix the quality. – F1Krazy Dec 11 '19 at 10:15
  • The claim is that you can die by being shocked by 12V. This answer says "Yes it is true, but I doubt deaths have occurred" and links to some anecdotes where people didn't die. This answer doesn't address the question. – Oddthinking Dec 11 '19 at 12:28
  • The quote from the question is states shock and not just death. So i was focuding on the reference and pith of the question, not its title and focusing on the answer which has 10 upvotes stating "no you cant get a shock from 12v" is equally erroneous so i guess i was giving caution to his error. – bandybabboon Dec 14 '19 at 06:24