burns

Started by chislerMD
This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.
C

chislerMD

New Member
7+ Year Member
Advertisement - Members don't see this ad
Quick question. If home appliance are 120 volts and can cause tetany how do people let go when they touch something and are burned. Thanks
 
Advertisement - Members don't see this ad
The current matters much more than the voltage.

This thing has 100,000+ volts.....

Van-de-Graaf-Generator-web.jpg

It just doesn't have much current, so it doesn't hurt you.


A/C can cause tetany at 3-9 milliamps.

But you probably aren't grabbing live wires in your home appliances too often...hence why I don't see too many people getting shocked.
 
fun anecdotal story......in the state I'm from electrician worker's comp is less than many other construction fields. They like to joke it's because they rarely ever get injured, it's either a 110 line that just reminds you not to touch it or a 440 and your wife gets a life insurance check.
 
So why do we worry about high voltage versus low voltage shocks. Does the high voltage have more potential to deliver higher current? Thanks
 
chislerMD said:
So why do we worry about high voltage versus low voltage shocks. Does the high voltage have more potential to deliver higher current? Thanks
Click to expand...
V=IR

And "we" don't care about the voltage, it's still the current. 440 lines have more current. Lightning has millions of volts, but isn't always fatal.
 
Depends on the currents running, and whether you're undergoing a myclonic jerk, or some other strong spasm. Chances it could hold you, or cause enough impulse to vector you elsewhere.
 
Last edited:
Advertisement - Members don't see this ad
Moose A Moose said:
Depends on the currents running, and whether you're under going a myclonic jerk, or some other strong spasm. Chances it could hold you, or cause enough impulse to vector you elsewhere.
Click to expand...

I do know a guy who had to literally beat a coworker with a 2x4 to get him off a live line when someone screwed up and flipped the wrong switch
 
gutonc said:
Due to the shock or the beating with a 2x4?

Too soon?
Click to expand...

I didn't know the gentleman and it wasn't on my site, so it's somewhat removed from me personally. But from the description I got they almost certainly would have broke something...it was pretty traumatic for the guy telling the story.
 
Advertisement - Members don't see this ad
Dr.McNinja said:
V=IR

And "we" don't care about the voltage, it's still the current. 440 lines have more current. Lightning has millions of volts, but isn't always fatal.
Click to expand...

I never did fully understand that part. V=IR, and when you touch a "wire" the two variables are the V in the wire and the R of your body that is going to determine the current that flows through your body. So technically, the current in the wire you're touching isn't even part of the equation that determines how much current is going to be flowing through your body given your body's resistance and the voltage drop between the wire and your body.

Or even put it even differently: you have a conductor (the wire) that has a certain fixed resistance R. The only independent variable is the voltage. Since copper is basically the only commonly used conductor for electricity distribution, R is always (more or less) constant no matter which power line you touch cause they're all copper. If you're always using the same R the only way to get low current is to use low voltage, and the only way to get high current is to use high voltage. So in that sense, "high voltage" wire in real life should be synonymous with high current wire. But it's not, and that confuses the hell out of me.
 
Last edited:
Brahnold Bloodaxe said:
I never did fully understand that part. V=IR, and when you touch a "wire" the two variables are the V in the wire and the R of your body that is going to determine the current that flows through your body. So technically, the current in the wire you're touching isn't even part of the equation that determines how much current is going to be flowing through your body given your body's resistance and the voltage drop between the wire and your body.

Or even put it even differently: you have a conductor (the wire) that has a certain fixed resistance R. The only independent variable is the voltage. Since copper is basically the only commonly used conductor for electricity distribution, R is always (more or less) constant no matter which power line you touch cause they're all copper. If you're always using the same R the only way to get low current is to use low voltage, and the only way to get high current is to use high voltage. So in that sense, "high voltage" wire in real life should be synonymous with high current wire. But it's not, and that confuses the hell out of me.
Click to expand...

You can ignore the resistance of the wire, whatever voltage drop will have occurred due to the resistance of the wire of very small as the resistance of copper wire is very small. The voltage at the outlet PR where ever you get shocked is still 120V.

The variable resistance is your body and where the electric is flowing to. If you touch the wire with wet fingers and are standing in a bathtub of water the resistance will be low and current will be high. (Water is a good conductor). If you have rubber boots on and your hands are dry the resistance will be much higher.
 
just take circuits. your adding a parrelell circuit to ground. since it is ac, you are both resistant and capacitant therefore your impedence plays a roll. the voltage of the line matters but so does the current. if there is no other load on the line thats where the problems start to begin even if there is a load, if youre lower impendence youre going to have hell of a shock

Sent from my VS986 using Tapatalk
 
I had a guy a year or 2 ago who locked onto an unopposed neutral for about 2 minutes by accident. Went in his right hand and tore out his left. Ended up with many fasciotomies and a 3 week burn icu stay.
 
You must log in or register to reply here.

Similar threads

M
Full thickness burns - white or charred?
Replies
5
Views
2K
brk81144
B