Questions about being electrically shocked (100-240V AC)

Thread Starter

rambomhtri

Joined Nov 9, 2015
388
Hi, I was thinking about what really happens when you get shocked and some questions came to my mind. I wanna know the answer out of curiosity and to understand a little bit better the dangers and injuries. I'll describe what I THINK happens under some situations and you correct me if I am wrong. Of course, there are no safety measurements (relays, fuses, breakers). I would love to know if in some situations, the fact the you are using 100V or 240V, changes anything:

1. You are isolated from your house's floor (ground?) wearing some regular sneakers. I believe that if you simply touch the hot wire with your fingers, the circuit is still open since you are isolated good enough from ground (I believe average sneakers with rubber-like soles protect you from 240V?) and nothing happens.
However, you could act as a capacitor and get charged and discharged @50-60Hz? (which sounds terrifying)
In that case, I don't know what kind of damage you would suffer.

2. Same situation as 1, but this time you are not isolated, quite the opposite, you are bare foot in your wet bathroom floor. I believe current would go from your finger to your feet, causing severe burns outside and inside your body, wherever the current went, it burned it. Also, I read a long time ago that the fact that some current could pass through your heart may cause your heart to skip beats or pump weirdly and totally mess it and kill you.

3. You are working with the average sneakers, "isolated", next to a wall outlet with the hot and neutral wires opened and exposed and you accidentally put your finger between them. My guess is your flesh closes the circuit and it gets burnt/completely destroyed, but you survive just fine. It would be like removing that part of your finger with a knife, which is not life threatening. I believe current would follow the shortest path, hence no current to your heart.

4. Same situation as 3, but this time no isolation from the floor. I guess you would have a combination of the injuries of number 2 and 3, since current would go all around. Or, may be, since your flesh is the least resistant path, current would still go from hot to neutral, even if you are touching ground with your bare feet. Which one is it?

Those are the most common accidents I can think of. Also... could you die or get seriously damaged by getting a shock that messes your heart beat but that is not powerful enough at all to even burn your skin?
Or any shock that gets current through your heart and messes your beat is already so powerful it burned your skin so easily?

I ask this because I remember reading cautions about those with a pacemaker, that a strong electromagnetic field could mess the device and cause your heart to not beat correctly. So, presuming you have an average healthy heart, could a shock (with no other damage) or a magnetic or electric or both fields cause your heart to stop working correctly?

Thank you so much!
 

MaxHeadRoom

Joined Jul 18, 2013
23,150
, the fact the you are using 100V or 240V, changes anything:

1. You are isolated from your house's floor (ground?) wearing some regular sneakers. I believe that if you simply touch the hot wire with your fingers, the circuit is still open since you are isolated good enough from ground (I believe average sneakers with rubber-like soles protect you from 240V?) and nothing happens.
However, you could act as a capacitor and get charged and discharged @50-60Hz? (which sounds terrifying)
In that case, I don't know what kind of damage you would suffer.
Obviously the higher the voltage, the higher the danger,
An example of whether current still flows if you are wearing insulated footwear etc, is when using one of the neon voltage-detect screwdrivers, you can be stood on a milk crate with your rubber soles and still get a light off the neon !
i.e. conduction to earth GND.
The worst shock I got was early in my career and accidentally thought I have removed a 230vac house fuse on a circuit I grasped the two conductors, one in each hand, fortunately the effect on my muscles was to fling me back, disconnecting the circuit.
Across two hands is about the worst due to the heart being in between.
I was about 20 at the time!
.
 

Irving

Joined Jan 30, 2016
1,572
Hi, I was thinking about what really happens when you get shocked and some questions came to my mind. I wanna know the answer out of curiosity and to understand a little bit better the dangers and injuries. I'll describe what I THINK happens under some situations and you correct me if I am wrong. Of course, there are no safety measurements (relays, fuses, breakers). I would love to know if in some situations, the fact the you are using 100V or 240V, changes anything:
1. You are isolated from your house's floor (ground?) wearing some regular sneakers. I believe that if you simply touch the hot wire with your fingers, the circuit is still open since you are isolated good enough from ground (I believe average sneakers with rubber-like soles protect you from 240V?) and nothing happens.
However, you could act as a capacitor and get charged and discharged @50-60Hz? (which sounds terrifying)
In that case, I don't know what kind of damage you would suffer.

If sneakers are good enough nothing happens. You might act as a capacitor to ground but very high impedance so you might feel a tingle but nothing harmful. HOWEVER I don't recommend you try it.

2. Same situation as 1, but this time you are not isolated, quite the opposite, you are bare foot in your wet bathroom floor. I believe current would go from your finger to your feet, causing severe burns outside and inside your body, wherever the current went, it burned it. Also, I read a long time ago that the fact that some current could pass through your heart may cause your heart to skip beats or pump weirdly and totally mess it and kill you.

All is true.

3. You are working with the average sneakers, "isolated", next to a wall outlet with the hot and neutral wires opened and exposed and you accidentally put your finger between them. My guess is your flesh closes the circuit and it gets burnt/completely destroyed, but you survive just fine. It would be like removing that part of your finger with a knife, which is not life threatening. I believe current would follow the shortest path, hence no current to your heart.

Mostly true, the burns could be severe and the nerve impulse could cause involuntary action which could throw you across the room causing other damage.

4. Same situation as 3, but this time no isolation from the floor. I guess you would have a combination of the injuries of number 2 and 3, since current would go all around. Or, may be, since your flesh is the least resistant path, current would still go from hot to neutral, even if you are touching ground with your bare feet. Which one is it?

Current could still flow through you and cause major problems - it will depend on relative impedances of two routes so not directly possible to say. Best not to try!

Those are the most common accidents I can think of. Also... could you die or get seriously damaged by getting a shock that messes your heart beat but that is not powerful enough at all to even burn your skin?
Or any shock that gets current through your heart and messes your beat is already so powerful it burned your skin so easily?

Yes, the burning is caused by heating effect of current density in amps per m^2. Spread across wide enough area the current could kill you with little or no burning. e.g people hit by lightening in heavy rain often have relatively little burning.

I ask this because I remember reading cautions about those with a pacemaker, that a strong electromagnetic field could mess the device and cause your heart to not beat correctly. So, presuming you have an average healthy heart, could a shock (with no other damage) or a magnetic or electric or both fields cause your heart to stop working correctly?

Not aware that magnetic fields can cause death though they can affect brain patterns (look up TMS therapy)
 

andrewmm

Joined Feb 25, 2011
1,497
Current flows from a high to a low voltage,

If you are insulated, and only touch one wire, then you are at one voltage , no current can flow. Think about birds sitting on a high voltage overhead power line, they are all at one voltage.

You are a capacitor, think about static yo get as you walk on some carpets. You are fine, you charge up, till you touch a means for the current to flow. Luckily we are bad capacitors, and the 240 V mains voltage will only give u a little charge ( compared to Kv from static ) , but if you instantly let go of the 240v with one hand and touch ground with the other whilst insulated you should get a small shock like you do with static.


All of your questions are about different resistances to ground for the charge to flow through.
the lower the resistance, for the same voltage , a higher current can flow, you will feel it more.
 

DickCappels

Joined Aug 21, 2008
7,449
My way of dealing with chances of electric shock directly from the mains is to make it a point to just not touch it. If I have to work on a fixture connected to the mains I pull the main breaker first, even though electricians don't bother. My usual approach is to just pay an electrician to take care of problems. The hard part is finding and keeping good ones.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
388
1. You are isolated from your house's floor (ground?) wearing some regular sneakers. I believe that if you simply touch the hot wire with your fingers, the circuit is still open since you are isolated good enough from ground (I believe average sneakers with rubber-like soles protect you from 240V?) and nothing happens.
However, you could act as a capacitor and get charged and discharged @50-60Hz? (which sounds terrifying)
In that case, I don't know what kind of damage you would suffer.

If sneakers are good enough nothing happens. You might act as a capacitor to ground but very high impedance so you might feel a tingle but nothing harmful. HOWEVER I don't recommend you try it.

2. Same situation as 1, but this time you are not isolated, quite the opposite, you are bare foot in your wet bathroom floor. I believe current would go from your finger to your feet, causing severe burns outside and inside your body, wherever the current went, it burned it. Also, I read a long time ago that the fact that some current could pass through your heart may cause your heart to skip beats or pump weirdly and totally mess it and kill you.

All is true.

3. You are working with the average sneakers, "isolated", next to a wall outlet with the hot and neutral wires opened and exposed and you accidentally put your finger between them. My guess is your flesh closes the circuit and it gets burnt/completely destroyed, but you survive just fine. It would be like removing that part of your finger with a knife, which is not life threatening. I believe current would follow the shortest path, hence no current to your heart.

Mostly true, the burns could be severe and the nerve impulse could cause involuntary action which could throw you across the room causing other damage.

4. Same situation as 3, but this time no isolation from the floor. I guess you would have a combination of the injuries of number 2 and 3, since current would go all around. Or, may be, since your flesh is the least resistant path, current would still go from hot to neutral, even if you are touching ground with your bare feet. Which one is it?

Current could still flow through you and cause major problems - it will depend on relative impedances of two routes so not directly possible to say. Best not to try!

Those are the most common accidents I can think of. Also... could you die or get seriously damaged by getting a shock that messes your heart beat but that is not powerful enough at all to even burn your skin?
Or any shock that gets current through your heart and messes your beat is already so powerful it burned your skin so easily?

Yes, the burning is caused by heating effect of current density in amps per m^2. Spread across wide enough area the current could kill you with little or no burning. e.g people hit by lightening in heavy rain often have relatively little burning.

I ask this because I remember reading cautions about those with a pacemaker, that a strong electromagnetic field could mess the device and cause your heart to not beat correctly. So, presuming you have an average healthy heart, could a shock (with no other damage) or a magnetic or electric or both fields cause your heart to stop working correctly?

Not aware that magnetic fields can cause death though they can affect brain patterns (look up TMS therapy)

Thank you for actually going point by point. That is what I was looking for and not general replies. Thank others, of course, for participating. Guys, really, I am not asking this because I am illiterate about electricity and wanna start fixing things, I already fix all kind of electric related problems, and electronics too. I was just curious about the specific topic "getting electrically shocked" and what really happens to your body. The topic is: if there is no protection and you get shocked, then what.

I am not going to try anything, hahaha, I am just curious about the theory of what would probably happen and how. I notice when you ask these kind of questions, people assume you know nothing about electricity and basically tell you "just call an electrician for whatever you are trying to do". I heavily doubt the average electrician (or electrical/electronic engineer) could answer these questions deeply and with knowledge of the phases. I remember I got one day a short lecture about security in the electric engineering degree, I remember a graph showing time and amps and the deadly zones, I saw clips of injuries, images, pretty much to scare us because we were about to start lab classes... I know if you do it in real life, an experiment like this with so many variables can turn many ways. I like to check what I know about electricity and apply it to real cases, guessing without trying what would happen.

Interesting enough, I guess when someone dies from an electrical shock, it's most likely the heart being contracted randomly (or may be getting stuck contracted for a while?), isn't it?

I am shocked about your lightning answer... are you telling me that if a lightning hits you, you don't die because it "destroys" you?
They rip apart tress, I was expecting that they would burn your skin and internals really nasty. If it is not like that, then what, the lightning simply messes with your heart and you die?
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
23,150
With a lightning strike, you are one conductor in the path of the overhead negatively charged storm cloud, it has been found that the in ground opposing positive charge follows the overhead cloud as it travels.
Waiting for a suitable conduction path.
 

Jim@HiTek

Joined Jul 30, 2017
20
"I ask this because I remember reading cautions about those with a pacemaker, that a strong electromagnetic field could mess the device and cause your heart to not beat correctly. So, presuming you have an average healthy heart, could a shock (with no other damage) or a magnetic or electric or both fields cause your heart to stop working correctly?"

Most everything you asked has been covered above except I didn't notice anything about skin resistance. If you are sweaty, if there's a lot of moisture in the air around you, the shocks to a misplaced hand will be even more severe. And the worst case of all is if you have an open wound and happen to touch a live circuit even at low voltage...that can stop your heart. 'Course for these scenarios you need a return circuit.

Whenever I'm working with live circuits over around 50 volts or so, I wear gloves AND rubber soled shoes. Just a habit. When standing on dirt, grass, or a puddle, I put down a layer of wood. Dry wood if possible.
 

andrewmm

Joined Feb 25, 2011
1,497
Ive had a work collage many decades ago, who was "shocked" the inquest viewed it that he bunt from the inside....

Its reckoned that above around 20mA across the heart muscle will stop or shock it into arrhythmic status, and you die.

A high voltage puts so much current through you that you cook,
if your "lucky" and its quick, its "only" the skin that gets burnt off,
If your unlucky like my collage, ...

If in doubt, watch the great ( IMHO) ) movie, the green mile film,
 

Audioguru again

Joined Oct 21, 2019
3,207
You talked about 120V or 240V "burning your skin off". But have you measured the 200k or more resistance of your skin and calculated the burning power? 120V into 200k= 0.072W which is almost nothing.
If your skin is soaked in salt water then it might be 10k ohms from side to side on a finger then the heating power is 1.4W that will burn but not badly if you jump away quickly. 240V produces 4 times the heating power.

Just now I measured 2M ohms from one hand to the other hand because I have not soaked myself in salt water for about 40 years.
The great lakes near me have fresh water but salt from winter roads has it getting salty.
120V into 2M is a current of 60uA that probably would not stop my heart. The heating would be only slightly more than nothing.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
388
You talked about 120V or 240V "burning your skin off". But have you measured the 200k or more resistance of your skin and calculated the burning power? 120V into 200k= 0.072W which is almost nothing.
If your skin is soaked in salt water then it might be 10k ohms from side to side on a finger then the heating power is 1.4W that will burn but not badly if you jump away quickly. 240V produces 4 times the heating power.

Just now I measured 2M ohms from one hand to the other hand because I have not soaked myself in salt water for about 40 years.
The great lakes near me have fresh water but salt from winter roads has it getting salty.
120V into 2M is a current of 60uA that probably would not stop my heart. The heating would be only slightly more than nothing.
I am always talking about 120V or 240V because I am applying this thread to home accidents, not in over 5000V areas. By the way, I never claimed anything about burning skin at X, I was assuming that, and I was open, I am, to someone telling me that that's not how that works. First of all, I expect that the resistance of your body heavily decreases, like with incandescent bulbs, when you touch a hot wire.

Are you saying that if you touch the hot and neutral wire of any house, or the hot wire and ground, you will not burn your skin almost anything, but will probably die because of heart arrhythmia?
That would be very interesting... I was/am expecting that if I touch the hot wire in a 240V outlet and I am not insulated at all, I will get black skin fairly easy, like chopping half of my finger. I could be wrong and that's why I created this thread.
 

AlbertHall

Joined Jun 4, 2014
11,317
One thing to take into account is that even a small current will make your muscles contract and if that happens to tighten your grip on whatever it was that you shouldn't have touched then that reduces the resistance, increases the current and whammo...
I still have the burn marks on my hands from a vacuum tube TV heater chain.
 

andrewmm

Joined Feb 25, 2011
1,497
240 V , especially as its AC, as shown does not pass much power through you to cause much heating,
but the current across the heart will stop it,

Thats why old sparky used a much higher voltage, and even then, they used care to make good contact with the head , so that electricity would flow through the heart, It was also DC.
 

Alec_t

Joined Sep 17, 2013
12,091
Way back in my youth I caught about 350VDC across my heart from a mains smoothing cap when I was adjusting something with a tool in one hand inside a tape recorder and inadvertently put my other hand on the chassis. One moment I was tinkering, the next I was picking myself off the floor from the opposite side of the room, where I'd presumably been thrown by muscle contraction. The intervening period is a complete blank.
 
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