Electrician4life
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- Virginia
References?
What would be an intelligent responce?
- Thread starter Hendrix
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References?
Electrician4life
Member
- Location
- Virginia
Based on the research of Professor Dalziel of the University of California, Berkeley, the effect of 60 Hz (cycles per
second) of alternating current on the human body is generally accepted to be as follows:
? 1 milliamp (mA) or less?no sensation?not felt (1,000 milliamps equal 1 amp)
? 3 mA or more painful shock
? 5 mA or more?local muscle contractions?50 percent cannot let go
? 30 mA or more?breathing difficult?can cause unconsciousness
? 50?100 mA?possible heart ventricular fibrillation
? 100?200 mA?certain heart ventricular fibrillation
? 200 mA or more?severe burns and muscular contractions?heart more apt to stop than fibrillate
? Over a few amps?irreversible body damage
While the Hz remained constant, the changing factor here is the current. If the main factor of fibrillation was Hz, wouldn't we see a negative effect sooner?
My intelligent response would be.... While all components of electricity play a factor in electric shock, current plays the most dominant role in the action.
second) of alternating current on the human body is generally accepted to be as follows:
? 1 milliamp (mA) or less?no sensation?not felt (1,000 milliamps equal 1 amp)
? 3 mA or more painful shock
? 5 mA or more?local muscle contractions?50 percent cannot let go
? 30 mA or more?breathing difficult?can cause unconsciousness
? 50?100 mA?possible heart ventricular fibrillation
? 100?200 mA?certain heart ventricular fibrillation
? 200 mA or more?severe burns and muscular contractions?heart more apt to stop than fibrillate
? Over a few amps?irreversible body damage
While the Hz remained constant, the changing factor here is the current. If the main factor of fibrillation was Hz, wouldn't we see a negative effect sooner?
My intelligent response would be.... While all components of electricity play a factor in electric shock, current plays the most dominant role in the action.
jwelectric
Senior Member
- Location
- North Carolina
Then read the first two sentences
jwelectric
Senior Member
- Location
- North Carolina
No, this was not the original question. The original question was;
The simple answer to this question is current
76nemo
Senior Member
- Location
- Ogdensburg, NY
Take a toll on how many electricians have ever been hammered the worse by yanking an unexpected neutral...... you can start from there. I think that is well over looked.
- Occupation
- Licensed Electrician
All of this is based on a certain level of voltage present. My solder gun puts out 200A at about 1.5V. I have touched the uninsulated heating element with my bare skin while it was energized. Have I cheated certain death?
jwelectric
Senior Member
- Location
- North Carolina
I put my cast iron skillet on a red hot eye of my stove and touch the skillet with my bare hand without getting shocked. Just don?t make sense does it?
Think I will do some studying on this?????
- Location
- Simi Valley, CA
No, but you've added on to the "stupid things I should never do again" list.:dunce:
Electrician4life
Member
- Location
- Virginia
Probably not. That being said, I am apt to follow the theories of a researcher who spent a good majority of time studying this very subject and creating a very well known safety device in the process.
*sigh*
<50mA = Insufficient power
50mA=200mA; Sufficient power, main cause of death = disruption of heart rhythm due to frequency
from your text death is from "heart ventricular fibrillation"
>200mA; main cause of death = cooking of tissues by delivered power in the form of heat
from your text death is from "severe burns"
Two different mechanisms for death. Though all components are present, different aspects of electricity are responsible for each type of death.
The simple answer to that question is "Which of your relatives do you want me to notify?"
Cause anyone trying to dumb down the theories of electricity that far is gonna get killed by the aspect they ignore.
- Location
- Massachusetts
That is the simple answer, but it is not an actuate answer.
K8MHZ
Senior Member
- Occupation
- Electrician
I'm with Bob. Time is indeed a factor to consider. Path through the body is another. Whether or not it is AC or DC also comes into play and I am sure there are other factors as well.
For instance, I have been hung up on a spark plug wire on a dirt bike. The ignition system ran around 10 thousand volts and I was above the let go threshold. Since this happened as a result of me pulling the plug wire off my bike that was running full speed in neutral as a result of a stuck throttle, I only had to endure the shock for a few seconds. I can tell you with no uncertainty that having to endure that same shock for several minutes would have been fatal.
In hospitals, there is a possibility of IV's becoming energized. It only takes a fraction of the current through an IV to be fatal as would a skin contact. That's why there is so much concern about available fault current in hospitals.
A person's health also affects the amount of current that would cause a fatality.
I have been hit by high output automotive ignition systems, around 30 kV. I have also been hit with 277 from a lighting circuit. Trust me, I'll take the current limited 30k over the 277 any day. A high voltage automotive system will deliver a shock like being grabbed and shook by the biggest girl in a country bar. Getting nailed with 277 is like getting kicked by her horse.
Electrician4life
Member
- Location
- Virginia
*Sigh* 50mA-200mA The frequency remained constant. Only the CURRENT increased.
A DC current has bee shown to create fibrillation, and was widely used in defib machines as early as 1959. Any frequency there?
Electrician4life
Member
- Location
- Virginia
Yes, I agree. There had to be sufficient voltage levels to push the current. But I didn't say voltage had no factor, I simply stated IMO, current played a larger role.
jwelectric
Senior Member
- Location
- North Carolina
And one can be so educated that they forget the basic fundamentals and think that they are smarter than the very text books from which they learned.
The safety manuals have taught the effects of current on the human body for more years than either of us without change.
jwelectric
Senior Member
- Location
- North Carolina
pray tell us what is
- Occupation
- Licensed Electrician
My wife had a similar opinion but I didn't think it was stupid at all.
I used it to burn off a wart. It was effective, saved me the cost of an office visit plus treatment at the doctor, the hassle and time lost going there, and it didn't hurt that bad.
And when the current increased enough, the manner of death changed. Above 50mA it only takes a fraction of a second to put you into fibrillation reqardless of the any further increase in current. Above 200mA death from burns follows the current/time curve. Oh, but what was that? Time? That would mean POWER not CURRENT.
Actually the defibrillation machines used clamped sinusoidal waves and have progressed to fancier wave forms since then. The use of different wave forms dramatically changes the success rate of restarting the heart. DC has a tiny chance to help not because it creates fibrillation but because it completely stops the heart. Then you hope the heart has enough health left to start itself correctly. Hmm, this would mean FREQUENCY has a substantial impact on heart rhythm. No no, we should have just cranked the DC current higher.
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