5 ms·

> If anyone would like to explain why that didn't kill me I'm all ears. What kills people is current, not voltage. With AC having your heart beat 50 times a se

by atoav 4y ago

> If anyone would like to explain why that didn't kill me I'm all ears. What kills people is current, not voltage. With AC having your heart beat 50 times a second can also cause you to die hours or even days after receiving a shock, but even that requires enough current to flow and cross your skin resistance. Go to ghe hospital even if you are alive and feel well after an electrical shock! Your heart may have suffered from this. That being said, there can be many things at play here. E.g. there could have been contact resistance between the live wire and the fixture, which would mean the current that could have flown through your body was limited by that resistance. The reason why you can touch an insulated wire is because there are megaohms of resistance between your hand and the wire. Lower that resistance gradually and there will be a point where you feel the electricity slightly, lower ot more and there is the shock. The most hurtful thing would piercing a wire through the skin, because then the skin resistance is gone. Aside from contact resistance it could also be that the bath the current took through your body was good (so more on the surface, not across the heart, but down one side of the body and so on). That being said, your description of the shock does not sound like a fully fledged 230V 50Hz shock to me (certified electical engineer). In my experience you will definitely notice it right away, e.g. because you suddenly just see black and a sharp pain including with extreme vibrations that feel like pure energy is hitting you with a brick in the face. Feeling the vibration like you described it and then making the decision to let go sounds like only a very small current was flowing.

weaksauce 4y ago
I'd hazard a guess that the person is using 120vac 60Hz instead of 230/50. 120vac is not as dangerous as 230 w.r.t. this kind of accident. I agree that they seem to have only held the fixture with one arm and probably standing on the leg with the arm outstretched or at least biasing weight to that leg to help reach. the current likely didn't go deep and didn't go across the heart. i agree that there wasn't a hard connection but must have had a path through the fixture that wasn't pure... likely a wire rubbed off the coating a bit but not quite fully so there was not a good connection to shock him with much current.
- usefulcat 4y ago
  They said it was in Portugal, which is 230v/50hz
  - weaksauce 4y ago
    ah missed that part good catch
- tremon 4y ago
  Since we're speculating, it may have been a halogen light fixture, which means there would have been a step-down transformer between the power switch and the light bulb. Depending on the specific type, it could have been as low as 12V/50Hz.
newaccount74 4y ago
> With AC having your heart beat 50 times a second can also cause you to die hours or even days after receiving a shock Can you point to any source for this? I have not been able to find any report of someone suddenly dying from cardiac problems days after an electric shock. It sounds kinda plausible, but I wonder if it is an urban legend. People lose limbs or die from severe electric burns, and people can die from cardiac arrest immediately after being shocked, but are there really cases where people have cardiac arrest days after an electric shock?
- Spooky23 4y ago
  Absolutely. Shocks can cause arrhythmias that are fatal hours or days later.
  - newaccount74 4y ago
    I've read a lot of assertions that this is true, but I'm looking for reports of this actually occurring. Either case studies from medical journals, or even newspaper articles.
    - Spooky23 4y ago
      Maybe start here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658458/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658458/
      - newaccount74 4y ago
        Thank you.
- leaving 4y ago
  50 times a second is hyperbole. Your heart cannot beat that fast because there is a refractory period between one contraction and the next. Before that could actually take place your heart would go into ventricular fibrillation, a disorganized electrical depolarization of heart muscle where many small electrical impulses cause chaotic and ineffective contractions of correspondingly tiny and disparate parts of the heart muscle. I've heard this idea before, that you can die hours or days after an electric shock without realizing anything is wrong, but I think it is very rare. An electrical injury can certainly trigger an abnormal heart rhythm, but you would probably notice most of those and, hopefully, go get a cardiogram. If you felt normal, but had a serious electrical injury to the heart that would later lead to fibrillation, one would have to postulate some sort of abnormal re-entrant (sort-of circular) depolarization current in the heart muscle that was very regular, say 60 beats per minute, but that was prone to deteriorate into fibrillation over time. That is what I recall about the matter, off the top of my head.
irrational 4y ago
> your description of the shock does not sound like a fully fledged 230V 50Hz shock Do they use 230V in Portugal?
- atoav 4y ago
  To my knowledge yes
- pezezin 4y ago
  All of Europe does.
coryrc 4y ago
Stone isn't very conductive, so I expect that majorly reduced the current.
- leaving 4y ago
  Water isn't very conductive, either, unless it has a lot of dissolved salts.
mhandley 4y ago
Way back when I was a student living in an old rented house in London, I went into the bathroom to find the bulb had blown. It was a pull cord switch, so I didn't know if it was on or off, but knew I wouldn't be so stupid as to stick my fingers in the bulb holder while changing the bulb, so no big deal if it was still live. Standing barefoot on the enamelled metal bath, I bent the cable so I could see how to screw the bulb in, and the ancient insulation on the cable split. I came to, lying in the bath with a huge bump on the back of my head. I knew exactly which path the current had taken because it hurt all down the right side of my body, but fortunately it mostly went down that side, not across my chest. So much for British bathrooms having pull-cord switches so you can't electrocute yourself.
- atoav 4y ago
  Congrats to not dying, in Germany you now could sue your landlord for wreckless endangerment.
- namaria 4y ago
  Safety guardrails won't work if you step around them... I'm glad you're fine, that sounds scary!
- fennecfoxy 4y ago
  As a Kiwi moved to the UK I think pull cords only exist because much fo the housing here was all built in the 60s-70s and hasn't been updated since. In NZ I'd never seen a pull cord until I moved to the UK. All of our electrics in bathrooms are certified for use around water there, including proper breakers/multiple RCDs etc. I think modernised UK homes that are now up to date often forgo the pull cords.
SamPatt 4y ago
I've been zapped too and there's no period of contemplation about what's happening. Just a moment of shock, then pain, followed by lots of cursing and then gratitude it wasn't worse.
bb88 4y ago
> What kills people is current, not voltage. From an engineer here, let's not continue this dangerous trope. High voltage breaks down resistance and allows current to flow. Current can only flow in the presence of voltage. Proof: A 1V 1000A power supply won't kill any one and won't give a shock. A 2000V .001A power supply might give quite a shock on the other hand, and depending upon any capacitance in the supply might just as well prove fatal.
- nicwilson 4y ago
  >A 1V 1000A power supply won't kill any one and won't give a shock. It very well could if the frequency is high enough. The skin is like a capacitor which acts like a short circuit at high frequency. DC is much less dangerous than AC at the same current/voltage for this reason.
- atoav 4y ago
  > A 2000V .001A power supply might give quite a shock on the other hand, and depending upon any capacitance in the supply might just as well prove fatal. What does the capacitor supply, that the PSU can't? Could it be discharge current? Before you accuse me of repeating dangerous tropes, please consider making sure to discuss it with the folks at VDE, because this is what it says in their (and the equivalent european) product norms and norms for electrical installations. When touching the positive pole of a 1V 1000A PSU (I assume DC) you won't have 1000A flowing through your body. It is not the rating current of the PSU that kills you, but the actual current going through your body. And how well that current will flow through your body depends on many things, including voltage, frequency (if we are talking AC), contact resistances, skin resistance, the internal resistance of your body, how big you are, your ground connection resistance, the duration of the current flow, etc. There is a reason we use high AC voltage for transportation of currents for long distances.
  - darken 4y ago
    I do see where the general objection to the "current kills" comes from, even if their reasoning got a bit muddled. All else equal, twice the voltage yields twice the current (and 4x the power). So while yes, it's the current that kills you, in the majority of circumstances high voltage = high current. Outside of explicitly current-limited setups (e.g. a Van de Graaff generator or a desktop ionizer), most higher voltage devices will kill you more easily. And so the "voltage doesn't kill" meme more often than not (IMO) gives laymen an undue sense of safety when working with higher voltages, at the benefit of appealing to the more electrically-inclined crowds sense of "being precisely correct". Just look at the dozens deaths a year from people messing with microwave transformers, trying to make some pretty wood lightning art, for an example of this.
m3047 4y ago
It's AC and the cycle (Hz) is x, then the voltage hits +/- max at 2x and also crosses 0 at 2x. Current in the system also crosses 0 at 2x although the phase angle is likely to differ from the applied voltage.

by atoav 4y ago

weaksauce 4y ago

I'd hazard a guess that the person is using 120vac 60Hz instead of 230/50. 120vac is not as dangerous as 230 w.r.t. this kind of accident. I agree that they seem to have only held the fixture with one arm and probably standing on the leg with the arm outstretched or at least biasing weight to that leg to help reach. the current likely didn't go deep and didn't go across the heart. i agree that there wasn't a hard connection but must have had a path through the fixture that wasn't pure... likely a wire rubbed off the coating a bit but not quite fully so there was not a good connection to shock him with much current.

usefulcat 4y ago
They said it was in Portugal, which is 230v/50hz
- weaksauce 4y ago
  ah missed that part good catch
tremon 4y ago
Since we're speculating, it may have been a halogen light fixture, which means there would have been a step-down transformer between the power switch and the light bulb. Depending on the specific type, it could have been as low as 12V/50Hz.

newaccount74 4y ago

> With AC having your heart beat 50 times a second can also cause you to die hours or even days after receiving a shock Can you point to any source for this? I have not been able to find any report of someone suddenly dying from cardiac problems days after an electric shock. It sounds kinda plausible, but I wonder if it is an urban legend. People lose limbs or die from severe electric burns, and people can die from cardiac arrest immediately after being shocked, but are there really cases where people have cardiac arrest days after an electric shock?

Spooky23 4y ago
Absolutely. Shocks can cause arrhythmias that are fatal hours or days later.
- newaccount74 4y ago
  I've read a lot of assertions that this is true, but I'm looking for reports of this actually occurring. Either case studies from medical journals, or even newspaper articles.
  - Spooky23 4y ago
    Maybe start here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658458/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658458/
    - newaccount74 4y ago
      Thank you.
leaving 4y ago
50 times a second is hyperbole. Your heart cannot beat that fast because there is a refractory period between one contraction and the next. Before that could actually take place your heart would go into ventricular fibrillation, a disorganized electrical depolarization of heart muscle where many small electrical impulses cause chaotic and ineffective contractions of correspondingly tiny and disparate parts of the heart muscle. I've heard this idea before, that you can die hours or days after an electric shock without realizing anything is wrong, but I think it is very rare. An electrical injury can certainly trigger an abnormal heart rhythm, but you would probably notice most of those and, hopefully, go get a cardiogram. If you felt normal, but had a serious electrical injury to the heart that would later lead to fibrillation, one would have to postulate some sort of abnormal re-entrant (sort-of circular) depolarization current in the heart muscle that was very regular, say 60 beats per minute, but that was prone to deteriorate into fibrillation over time. That is what I recall about the matter, off the top of my head.

irrational 4y ago

> your description of the shock does not sound like a fully fledged 230V 50Hz shock Do they use 230V in Portugal?

atoav 4y ago
To my knowledge yes
pezezin 4y ago
All of Europe does.

coryrc 4y ago

Stone isn't very conductive, so I expect that majorly reduced the current.

leaving 4y ago
Water isn't very conductive, either, unless it has a lot of dissolved salts.

mhandley 4y ago

Way back when I was a student living in an old rented house in London, I went into the bathroom to find the bulb had blown. It was a pull cord switch, so I didn't know if it was on or off, but knew I wouldn't be so stupid as to stick my fingers in the bulb holder while changing the bulb, so no big deal if it was still live. Standing barefoot on the enamelled metal bath, I bent the cable so I could see how to screw the bulb in, and the ancient insulation on the cable split. I came to, lying in the bath with a huge bump on the back of my head. I knew exactly which path the current had taken because it hurt all down the right side of my body, but fortunately it mostly went down that side, not across my chest. So much for British bathrooms having pull-cord switches so you can't electrocute yourself.

atoav 4y ago
Congrats to not dying, in Germany you now could sue your landlord for wreckless endangerment.
namaria 4y ago
Safety guardrails won't work if you step around them... I'm glad you're fine, that sounds scary!
fennecfoxy 4y ago
As a Kiwi moved to the UK I think pull cords only exist because much fo the housing here was all built in the 60s-70s and hasn't been updated since. In NZ I'd never seen a pull cord until I moved to the UK. All of our electrics in bathrooms are certified for use around water there, including proper breakers/multiple RCDs etc. I think modernised UK homes that are now up to date often forgo the pull cords.

SamPatt 4y ago

I've been zapped too and there's no period of contemplation about what's happening. Just a moment of shock, then pain, followed by lots of cursing and then gratitude it wasn't worse.

bb88 4y ago

> What kills people is current, not voltage. From an engineer here, let's not continue this dangerous trope. High voltage breaks down resistance and allows current to flow. Current can only flow in the presence of voltage. Proof: A 1V 1000A power supply won't kill any one and won't give a shock. A 2000V .001A power supply might give quite a shock on the other hand, and depending upon any capacitance in the supply might just as well prove fatal.

nicwilson 4y ago
>A 1V 1000A power supply won't kill any one and won't give a shock. It very well could if the frequency is high enough. The skin is like a capacitor which acts like a short circuit at high frequency. DC is much less dangerous than AC at the same current/voltage for this reason.
atoav 4y ago
> A 2000V .001A power supply might give quite a shock on the other hand, and depending upon any capacitance in the supply might just as well prove fatal. What does the capacitor supply, that the PSU can't? Could it be discharge current? Before you accuse me of repeating dangerous tropes, please consider making sure to discuss it with the folks at VDE, because this is what it says in their (and the equivalent european) product norms and norms for electrical installations. When touching the positive pole of a 1V 1000A PSU (I assume DC) you won't have 1000A flowing through your body. It is not the rating current of the PSU that kills you, but the actual current going through your body. And how well that current will flow through your body depends on many things, including voltage, frequency (if we are talking AC), contact resistances, skin resistance, the internal resistance of your body, how big you are, your ground connection resistance, the duration of the current flow, etc. There is a reason we use high AC voltage for transportation of currents for long distances.
- darken 4y ago
  I do see where the general objection to the "current kills" comes from, even if their reasoning got a bit muddled. All else equal, twice the voltage yields twice the current (and 4x the power). So while yes, it's the current that kills you, in the majority of circumstances high voltage = high current. Outside of explicitly current-limited setups (e.g. a Van de Graaff generator or a desktop ionizer), most higher voltage devices will kill you more easily. And so the "voltage doesn't kill" meme more often than not (IMO) gives laymen an undue sense of safety when working with higher voltages, at the benefit of appealing to the more electrically-inclined crowds sense of "being precisely correct". Just look at the dozens deaths a year from people messing with microwave transformers, trying to make some pretty wood lightning art, for an example of this.

m3047 4y ago

It's AC and the cycle (Hz) is x, then the voltage hits +/- max at 2x and also crosses 0 at 2x. Current in the system also crosses 0 at 2x although the phase angle is likely to differ from the applied voltage.