Electricity shock's

Thread Starter

loosewire

Joined Apr 25, 2008
1,571
I can remember when my hand got too close a large radio transformer,just thinking about it I can still fell the way It slamed me. Another time I touched the antenna terminal near a fire place,I found my self halfway across the room.I can see work bench and fire place and fell awfull jolt.I got hit by tv high voltage a few time's,but the jolt from the transformerI fell visalize as I post this. Any other experience's you guy,s want to share. LOOSEWIREP.S. My second post on laptop with wi-fi,checking for public wi-fi location's,first option is Border's and Barne's and Noble's,are they global book store's.Dave,at Border's they have platform and stool,If you have the nerve to get upon the stool and patron's lounging on couche's,you can have your say.I tryed it once,about 25 people no one would look me in eye's. Any thing like that any where guy's and girl's.
 
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Bernard

Joined Aug 7, 2008
5,263
Tecktronics published a note on electrical effects on humans; the thing I remember is 50 milli Amps is the crosover point to lethality, with many exceptions.
 

Wendy

Joined Mar 24, 2008
21,848
I think the exception is the circuit path. If it crosses your heart that's it, you're done. Just my opinion though.

I remember seeing a fellow tech (I was the lead tech on the line at the time) touch 90VDC on a old telephone circuit. He froze, the slowly toppled backwards on a very high chair (the kind that lab was using at the time). I'm afraid I didn't make any friends that day, I asked him if he was OK and he affirmed he was, and I broke out laughing. This really pissed him off, guess he was still smarting.
 

Geir

Joined Jul 28, 2008
6
Memo to self:
Even though the leads coming off the trafo-circuitboard (220V -> 12V) isn't much, there are still paths beneath that hold and lead 220V.
Conclusion: Don't hold the circuitboard flat in your hand when connecting the power!! The arm feels a bit...numb...afterwards.

PS! As far as I know, 6mA across the heart is lethal!

From Wiki:
A low-voltage (110 to 220 V), 50 or 60-Hz AC current through the chest for a fraction of a second may induce ventricular fibrillation at currents as low as 60 mA. With DC, 300 to 500 mA is required. If the current has a direct pathway to the heart (e.g., via a cardiac catheter or other kind of electrode), a much lower current of less than 1 mA, (AC or DC) can cause fibrillation. Fibrillations are usually lethal because all the heart muscle cells move independently. Above 200 mA, muscle contractions are so strong that the heart muscles cannot move at all.
 

Unregistered

Joined Dec 31, 1969
0
After 20+ years in the industry and teaching in the industry, here is my 2 cents on electric shock.

0.001A - tingling sensation is felt
0.01A - Involuntary muscle movment/contraction occurs
0.1A across the heart - fatal with no medical help

Current not woltage is the killer. In the U.S. more people are are killed by 120Vac than any other voltage.

A technician decided he wanted to know the resistance of his blood, so he poked a probe into the finger of one hand (breaking the skin), and then the a finger on his other hand. If you are familar with how an ohmmeter works... well, he recieved a lethal shock through his heart.

--James
 

thingmaker3

Joined May 16, 2005
5,073
A technician decided he wanted to know the resistance of his blood, so he poked a probe into the finger of one hand (breaking the skin), and then the a finger on his other hand. If you are familar with how an ohmmeter works... well, he recieved a lethal shock through his heart.

--James
James, can you provide a source for this story? I would like to read into it further. Did he put the probes all the way into his flesh and then put the leads in the meter? What size battery was in the meter? How did he manage to manipulate the second probe with the first one stuck in his finger?
 

jpanhalt

Joined Jan 18, 2008
7,906
Thingmaker3,

Maybe it's just me this morning, but I find your signature comment particularly applicable to the comment above. Thanks for the smile. John
 

Mark44

Joined Nov 26, 2007
626
James, can you provide a source for this story? I would like to read into it further. Did he put the probes all the way into his flesh and then put the leads in the meter? What size battery was in the meter? How did he manage to manipulate the second probe with the first one stuck in his finger?
I'm skeptical of this story. It's hard for me to imagine that the current produced by a small 9v battery or a couple of AA cells would prove fatal
 

beenthere

Joined Apr 20, 2004
15,808
Ohmmeters do not produce enough voltage to push a fatal current (freezing the heart muscle). Or producing an electrotetanus sufficient to prevent the guy from removing the probes. Sounds like urban legend to me.

The testing methodology is silly, too.
 

Thread Starter

loosewire

Joined Apr 25, 2008
1,571
Underwriters lab don't suggest a fuse in small battery operated radio's.
Car radios are fused, so it get down to current protection.
Fire protection in auto is also a concern.

p.s. Remember when radio's before transistor,some radio's had large,what
was called (a) (b) batteries which was large enough to supply some
current. Maybe some one got there story and wire's crossed.Help me sort this out.
 
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Mark44

Joined Nov 26, 2007
626
The old Avo7 multimeter used a 22.5 Volt battery on some resistance ranges. That is more than enough voltage to kill someone if you bypass the skin resistance.
I've been shocked a few times by 120v AC while changing a light switch in a hot circuit (did it at night, without a flashlight, and wanted the light to see what I was doing). All I felt was an intense tingle for a fraction of a second. So voltage, in and of itself, is not the key, nor is current, in and of itself. I wouldn't dream of working on a 220v circuit that was live, though.

Granted, I wasn't making a good solid connection, so it's hard to say how much power I was dissipating.
 

Thread Starter

loosewire

Joined Apr 25, 2008
1,571
Mark 44-Think of all the changes in the last 30 years. Plastic has save
more live than can be estimated.Do you recall the rubber slipper's the
the nylon rug,plastic cover plates,code grounded curcuit.People don't
reach from the frig and sink and die any more.Technology has save
more live and at the same time people are less compelled to be
concerned about electticty,electronic.The remote is plastic and most
people would not know it has batteries .
 

Mark44

Joined Nov 26, 2007
626
Mark 44-Think of all the changes in the last 30 years. Plastic has save
more live than can be estimated.Do you recall the rubber slipper's the
the nylon rug,plastic cover plates,code grounded curcuit.People don't
reach from the frig and sink and die any more.Technology has save
more live and at the same time people are less compelled to be
concerned about electticty,electronic.The remote is plastic and most
people would not know it has batteries .
Loosewire,
And your comment relates to this thread -- how?
 

theamber

Joined Jun 13, 2008
321
After 20+ years in the industry and teaching in the industry, here is my 2 cents on electric shock.

0.001A - tingling sensation is felt
0.01A - Involuntary muscle movment/contraction occurs
0.1A across the heart - fatal with no medical help

Current not woltage is the killer. In the U.S. more people are are killed by 120Vac than any other voltage.

A technician decided he wanted to know the resistance of his blood, so he poked a probe into the finger of one hand (breaking the skin), and then the a finger on his other hand. If you are familar with how an ohmmeter works... well, he recieved a lethal shock through his heart.

--James
Bed time stories...
I see it this way; the human boby is conductive. Dry skin is not a good conductor this serves as a shield enough voltage will break the skin barrier.
I haven been shoked docens of times up to 840 VDC that made a hole through my skin and flesh. Also 220 and 120 VAC many times. I am pretty sure you guys had too.
For the chickens out there... I want to see DEATHS proves of people WORKING on electronic equipment no bedtimes stories.

Now the real dangers come from high frequencies.
Inside the human body there are ellectric currents. I have seen also claims that human frequencies vary from a low number of Hz to around 300Hz.
An
EEG shows the electrical activity of neurons in the brain.
An EKG show what the heart is doing. Naturally a real damage depends on frequency and intesity :
High frequency and intensity may pass through (e.g. X rays).
Higher frequency 20kH to GHz (radio frequencies) have less and less biological effect (expect from heating if intensity is very high (such as in the microwave oven).
Very High frequencies (UV, X ray, gamma rays) may be dangerous.
It has to have certain minimal energy (frequency) to be able to break a chemical bond of the biomolecules.
High power RF burns those can cause real long term internal damage.
So using high frequency trasmitters may be worse than working on electronic equipment that includes CRTs TVs.
The guy that died with the meter probably...Then he was 80 years old and had a pacemaker.



 

Thread Starter

loosewire

Joined Apr 25, 2008
1,571
I thought that you might go back to the electrical box and see if there
were any insulating factor's that prevented a more deadly shock.
Like carpet floor or insulated lamp base or other.I started the thread by recounting the shock's that I can still feal now,how I felt the slam from
touching a radio with a large power transformer. I read your post and respect you very much.Some of my post are hard to read,that just my way,again I respect your work
 

theamber

Joined Jun 13, 2008
321
Thanks Thingmaker3, I said electronics not electrical equipment nor natural thunderbolts.
I was in Spain not long ago in one electrical company... I remember this young guy from Russia... the next day he wasn't there any more but he was working with power lines.

I want to see probe of someone being killed by for example the monster...a 'CRT TV set' lets say. That may deter me from opening another TV set.
I think that eating junk food, driving or walking on the streets today has a higher death risk than electrocution from working on ELECTRONIC equipment.

Check this report:
http://www.cma.ca/multimedia/staticContent/HTML/N0/l2/cjs/vol-48/issue-4/pdf/pg289.pdf

United States, estimates of fatalities
due to electrocution have been
estimated at 5 per 1 million population
annually.2–5 Death attributed
specifically to lightning has varied
considerably depending on geography,
with the highest rates of approximately
1 per 1 million reported
from southern US.6,7 Male gender
and an occupation requiring exposure
to electric current have been
proposed as risk factors for severe
electrical injury, although the actual
risks have been poorly quantified.
 
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thingmaker3

Joined May 16, 2005
5,073
I said electronics not electrical equipment nor natural thunderbolts.
--------
I want to see probe of someone being killed by for example the monster...a 'CRT TV set' lets say. That may deter me from opening another TV set.
There are a plethora of search engines to choose from. May your effort be fruitful.
 

theamber

Joined Jun 13, 2008
321
There are a plethora of search engines to choose from. May your effort be fruitful.
No I am not interested, my point is that it is so remotely near to imposible to get killed by working on a TV than it is from stepping on a banana peel. And that should not be a deterrent for any healthy adult with a basic understanding of electricity to work with.
There are so many real dangers arround us we just need to exercise the logical and propper care... but have this for certain when your time comes noone knows when and where.
I even used to get shocked with friends for fun everywhere with a taser gun and I am still here.
Electricity is fun, everyone should respect it but never be horrified by it.
This I said.
 
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