Electrocution Current

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james_mcquade

Senior Member
I am currently working for a company in Tennessee and the safety guy asked
me how much current it took to get electrocuted. i tried to explain the various situations that existed at the plant, working indoors versus being hot and sweaty, and several other things.

the guy is honestly trying to take in everything i say, but is having a hard time.

is there an article or some other electronic file that would help me explain his question?
thanks in advance,
james
 
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Jljohnson

Senior Member
Location
Colorado
There are many variables to that answer as you well know, judging from the info in your post. The individuals body resistance is the greatest varible of them all. With that said, the standard for GFI receptacles is to trip @ 5 milliamps of leakage, so 6 milliamps would be the way I would answer that question. Keep in mind though, under the right conditions, even 5 ma of current could stop a beating heart.
 
cschmid

cschmid

Senior Member
Location
Northern cold country
I believe the sites listed below will help you out...I know the IAEI has some info as well but was unable to locate it... Good luck

Electric current can cause injury in three main ways:

1) Cardiac arrest due to the electrical effect on the heart.
2) Muscle, nerve, and tissue destruction from a current passing through the body.
3) Thermal burns from contact with the electrical source.

http://www.uic.edu/labs/lightninginjury/Electr&Ltn.pdf

http://www.elec-toolbox.com/Safety/safety.htm

http://www.cdc.gov/niosh/elecovrv.html
 
zog

zog

Senior Member
Location
Charlotte, NC
6mA will not stop a beating heart under any conditions unless maybe you are one cheesebuger away from a heart attack anyways. A GFCI operates at 5mA because it is above the preceptable current (1mA) but below the cant let go current.

Based on a 120VAC shock 1/2 second duration to an average human 10-20mA is where a loss of muscle control occurs which may cause you to become stuck on the circuit, increasing the duration, if the duration is long enough that could be fatal. Respitory paralaysis occurs at about 20-50mA and could be fatal if CPR is not applied within 4 minutes. 50-100mA there is a 5% chance your heart will go into fibrilation which can very easily be fatal, 100-200mA there is a 99.5% chance you will go into fibrilation. OSHA uses 100mA as the fatal current for the basis of many of thier safety rules.

Again these are based on certian conditions, changing conditions may affect the outcome of different current levels. The IEC 479 has all the info you would ever want about current levels.
 
drbond24

drbond24

Senior Member
Location
Barboursville, West Virginia
I thought that it was the frequency that had the most to do with fatality. The frequency of the current flow throught the body (i.e. 60 Hz) messes with the electrical impulses in the heart, effectively turning it off. If this is completely stupid, somebody correct me. I don't remember where I got that.

Wouldn't looking at a defibulator be beneficial here? Whatever the electrical specs are that turn on a stopped heart would be the same for turning off a beating one, wouldn't it?

These statements are toward the cardiac arrest situation, not the others. Obviously if enough current passes through you it wouldn't matter what the frequency was.
 
JohnJ0906

JohnJ0906

Senior Member
Location
Baltimore, MD
zog said:
6mA will not stop a beating heart under any conditions unless maybe you are one cheesebuger away from a heart attack anyways. A GFCI operates at 5mA because it is above the preceptable current (1mA) but below the cant let go current.
Click to expand...

I agree, if we are discussing a healthy adult.

I was under the impression that 5mA was ABOVE the let-go threshold for most children?
 
cschmid

cschmid

Senior Member
Location
Northern cold country
yes that is helpful but that does not give a listing of what body weight they used for a base. If you applied a contant voltage with 5ma to an 80lb child and the same to a 180lb adult you would get different results..
 
radiopet

radiopet

Senior Member
Location
Spotsylvania, VA
One of the charts like the one Roger posted that I use is similar and it is based on 86kg man....not sure that helps much on the one Roger posted......

I guess what is more important as educators to convey is that YES...even 6-10 mA could cause death......depending on the current, condition and so on.

I like the old saying in my classes..." it only takes 1/10th of a AMP to kill ya " and it gets their attention.
 
drbond24

drbond24

Senior Member
Location
Barboursville, West Virginia
Talk about getting your attention:

In college, the first thing we did in lab was to measure our own resistance and calculate what level of voltage it would take to push lethal current through our body (no, I don't remember what current we assumed was lethal). It was definitely an attention getter.
 
zog

zog

Senior Member
Location
Charlotte, NC
"yes that is helpful but that does not give a listing of what body weight they used for a base"

The IEC 479 Tables use the "Average body weight of an electrician" which is listed as 145 Lbs!
 
MAK

MAK

Senior Member
Location
Massachusetts-Boston
I think how the current is applied would be another variable to consider. If it is straight across the chest versus, through 1 hand to the other then a person would be more prone to electrocution at a lower current due to higher resistance in the limbs. Also it would raise the point that not every person has the same resistance through their limbs. Some people may have a higher amount of keratin in their skin which from what I have been taught would raise your resistance to electric shock.
 
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sparky_magoo

sparky_magoo

Senior Member
Location
Reno
zog said:
"yes that is helpful but that does not give a listing of what body weight they used for a base"

The IEC 479 Tables use the "Average body weight of an electrician" which is listed as 145 Lbs!
Click to expand...

I wish!:grin:
 
D

DUCKMAN

Member
james_mcquade said:
I am currently working for a company in Tennessee and the safety guy asked
me how much current it took to get electrocuted. i tried to explain the various situations that existed at the plant, working indoors versus being hot and sweaty, and several other things.

the guy is honestly trying to take in everything i say, but is having a hard time.

is there an article or some other electronic file that would help me explain his question?
thanks in advance,
james
Click to expand...

I am an OSHA instructor, and my text states that 75mA can cause heart fibrillation.
 
W

wptski

Senior Member
Location
Warren, MI
What about duration of the shock? The UL standards for a GFCI allow up to 5600ms at 6ma. Any specs that I've seen for a GFCI state 4-6ma minimum trip current and a maximum trip time of <25ms but that's not at 4-6ma. I quized Leviton and P&S about this but received no reply.
 
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