FRANKY CHAVARIN
Member
How much current does it take to freeze your hand to a device?
Aritcle 250
- Thread starter FRANKY CHAVARIN
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chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
roger said:
I'm going to have to delete this post as per the 'No more click here' Forum rules.
- Location
- Massachusetts
chris kennedy said:
Chris, did you check the OPs profile?
K8MHZ
Senior Member
- Occupation
- Electrician
Since this thread hasn't been locked yet, here goes....
When I was in school we had a crank type telephone generator. Friend A would crank while friend B would hold on to the leads and compete for the highest voltage attained. I won at around 110 volts. The other guys would say stop at 70 to 90 volts. At around 60 volts we couldn't let go. So, let's do the math....
My body that day showed 600 to 1200 ohms. The resistance of our bodies is not constant, and that is why it matters where the current path is when determining a safe or unsafe value. Along with the uncertainty of resistance, there is also a major concern of which internal organs get to become conductors, but I digress....
Using Ohm's Law we can see that in *my* case, I clamped on at 50 to 100 milliamperes. That amount of current can be fatal.
Now, at 110 volts I was getting hammered pretty good, could not let go and counted on trusting my friend to stop cranking the generator when I said to stop. When working on live 120 volt equipment, you do not have the luxury of ramping up the voltage until you can't take it any more and you don't have the luxury of telling the circuit to shut off in some manner.
So, to answer your question in terms of the layman, it takes half or less the current passing through the resistance of a person's body from a live 120 volt box for them to clamp on.
There is also more than twice the voltage present in there to kill you if it goes through the wrong path in your body. In January a Local 697 Journeyman was killed by 56 volts flowing through a supposedly non-energized grounding conductor.
To sum things up, anytime you are working on live equipment (whether you know it's live or not) you are putting yourself in harm's way.
When I was in school we had a crank type telephone generator. Friend A would crank while friend B would hold on to the leads and compete for the highest voltage attained. I won at around 110 volts. The other guys would say stop at 70 to 90 volts. At around 60 volts we couldn't let go. So, let's do the math....
My body that day showed 600 to 1200 ohms. The resistance of our bodies is not constant, and that is why it matters where the current path is when determining a safe or unsafe value. Along with the uncertainty of resistance, there is also a major concern of which internal organs get to become conductors, but I digress....
Using Ohm's Law we can see that in *my* case, I clamped on at 50 to 100 milliamperes. That amount of current can be fatal.
Now, at 110 volts I was getting hammered pretty good, could not let go and counted on trusting my friend to stop cranking the generator when I said to stop. When working on live 120 volt equipment, you do not have the luxury of ramping up the voltage until you can't take it any more and you don't have the luxury of telling the circuit to shut off in some manner.
So, to answer your question in terms of the layman, it takes half or less the current passing through the resistance of a person's body from a live 120 volt box for them to clamp on.
There is also more than twice the voltage present in there to kill you if it goes through the wrong path in your body. In January a Local 697 Journeyman was killed by 56 volts flowing through a supposedly non-energized grounding conductor.
To sum things up, anytime you are working on live equipment (whether you know it's live or not) you are putting yourself in harm's way.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
FRANKY CHAVARIN said:
Well to tell you the truth I died from 120 volts as a kid. It was really bad.
Actually I was 13 and was working on a live 120 volt circuit that I thought was dead. I was standing in water with sneakers on and I grabbed hold of the circuit. It took me about 2 seconds or so to actually release the cable from my hands. My muscles locked around the wire but somehow I was able to free myself. It was fun..
I sat down for awhile after that one. I have been hit by 277 with no problem at all. Different circumstances.
M. D.
Senior Member
I was about thirteen ,..standing barefoot on dewy grass with a metal cased craftsman drill , grinding pad to feather the lead paint after we scraped the 120 year old house I grew up in ,..no third prong no GFCI ,..squeezed the trigger and that was it . I could not let go ,..I could not speak.
Thank God my brother saw what was happening and unplugged the extension cord. Had he not , I most likely would have passed out and hopefully the action of hitting the ground would free the drill .. I'm glad my brother was there .
Thank God my brother saw what was happening and unplugged the extension cord. Had he not , I most likely would have passed out and hopefully the action of hitting the ground would free the drill .. I'm glad my brother was there .
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