Flummoxed by a small meter
Discussion
Klemheist said:
Around 15 years ago I was working in a bakery and the Maintainance fitter wired up an inline 12volt dc plug and socket to a small fork lift incorrectly, he had damp hands, picked up the pinned end which was live and burnt 3 holes straight through his hand, no fuses 12 volt battery system 3 brass pins sticking out the back of the hand bubbling skin not pretty.
That's impossible as described, sorry.Globulator said:
Klemheist said:
Around 15 years ago I was working in a bakery and the Maintainance fitter wired up an inline 12volt dc plug and socket to a small fork lift incorrectly, he had damp hands, picked up the pinned end which was live and burnt 3 holes straight through his hand, no fuses 12 volt battery system 3 brass pins sticking out the back of the hand bubbling skin not pretty.
That's impossible as described, sorry.
Klemheist said:
I would have agreed with you If I hadn't seen it but It did happen. I suppose a couple of hundred amps can burn through anything and he couldn't let go. Feel free to try it out.
His skin resistance and the internal resistabce of the power source must have been extremely low to draw that much current!Klemheist said:
I would have agreed with you If I hadn't seen it but It did happen. I suppose a couple of hundred amps can burn through anything and he couldn't let go.
It's power that burns through things, and yes 12V at 200A = 2400W.
Klemheist said:
Feel free to try it out.
I have, many times!!Skin resistance can't get that low. It really can't.
What your friend actually did was cause a short circuit in the plug, which heated up like a fire and burnt his hand. So yes, very hot objects are dangerous, shorting out batteries is dangerous.
12V on skin however is not, unless you get a ring between the terminals (which again heats up - the damage is the heat - not the electricity)..
Klemheist said:
I've been an NICEIC registered electrician and company owner for 30 years and I used to think I knew everything about electricity, but I do know a fork lift battery can push out many hundreds of amps to a low resistance.
All lead acid batteries can. In fact Nicad, NimH, Lipo, Lion, LiFe can too.
Hell, even Alkalines can have a go.
Skin however is not a low resistance, even if you just dipped it in the Dead Sea. He caused a short in the plug, no mystery there.
Your example is a valid safety observation: without a fuse these low voltage batteries can still be dangerous.
xllifts said:
And that shows your ignorance its the amps that Kill you as little as 20a dc can kill whether its 12v DC or 240ac it'll be the amps that'll kill you. 100ma will stop your heart!
But you knew that anyway didn't you.
Two things.But you knew that anyway didn't you.
Firstly I = V/R. Therefore lower voltages are safer assuming the resistance stays the same. 12V through the body would pass a current 20 times lower than mains (240V), and as mentioned shocking the heart would be impossible unless the body was pickled.
Secondly, DC current affects the heart to a much lesser extent than AC.
However as also mentioned, large batteries are somewhat dangerous due to the amount they can heat an object when shorted, also a spark in the eye is not nice!
Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff