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OT: Story about a guy killed demonstrating to kids how safe a 12v car battery is?

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  • Tim The Grim
    replied
    I was working alone on a blistering hot summer night in ‘89, in a shop with no AC. My primary responsibility that night was getting a bunch of SmartCam programs ready for the next mornings wire EDM run. We had a production sinker job set up in our old Charmilles Eleroda D4 and my boss asked if I’d keep that running as well. There was only 10 feet between my PC and the EDM so it was easy to hear when it finished and retracted the ram.

    It was after 11pm, I’d been there since 8am and I was wringing wet with sweat and dog tired.

    I put a new piece in the fixture and without thinking I grabbed the ram and pulled down the clunky metal bar that initialized the cut. I honestly don’t know how much electricity went straight through my chest from my left hand to my right, but it was a lot. I fell backwards and before I hit the floor I swung back towards the PC and picked up the phone. I couldn’t tell if I had a pulse, but I dialed the first 6 digits of the police phone # and waited a minute or so until I felt my heart start beating again. I was 36 years old, in great physical condition.
    I decided to call it a night, drove home, smoked a tasty bowl of weed and just thanked my lucky stars that they wouldn’t find me dead on the floor that next morning.

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  • tlfamm
    replied
    In the early 1970's I was working in a development of new slab houses constructed of prefab walls (maybe 1-5/8" thick) with foam insulation and electrical wiring installed at the factory. The walls were fastened together on-site with 6" screws driven in with the impact-screwdriver technology of the day: a 14"-long 110 volt AC device, maybe 3/8 or 1/2 horsepower, all aluminum housing, a bit hefty, etc.

    While driving in a screw at shoulder height one day, there was a tremendous crash of thunder, the crack of lightning, and suddenly I'm rising up on the balls of my feet and experiencing something I can only describe as the sensation of "burnt lungs". I was a little freaked, but not really injured, and continued work after a short break.

    I _think_ that some kind of induced current travelled up the ground wire to the screw-gun, delivered thence into my hands by the gun's aluminum housing.

    (The grounding provision for the temporary electrical service at construction sites might sometimes be sub-par - in this case the ground might have been floating.)

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  • danlb
    replied
    I worked at the phone company in a job that entailed soldering hundreds of live wires per shift. ALL of the wires had 48V on them and we worked with them with bare hands or fingerless leather gloves. Technically, there were wires with more voltage and some with less. They were at 24V, 48V and 90V depending on the state of the phone call.

    I mention this because we only got shocked by the 90V that is applied when the phone was ringing. Despite sweating enough too soak through the leather gloves, we did not get a bite from the wires with 48V or less. But when I got a sting from 90V I could be sure that I'd get another since I'd start sweating like a stuck pig.

    The 10ma that is fatal is when the 10ma goes THROUGH THE HEART. If the skin is wet, as in the story about the swimming pool, the current flows across the skin and not so much through the organs.

    BTW, the majority of tools that have insulated handles are made that way to prevent unintended shorts between electrical components.

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  • jdunmyer
    replied
    The worst shock I ever got was many years ago, using my VTVM (remember them) to check the B+ in a Halicrafters radio receiver. I think it was 300 VDC. My arm actually hurt for a while afterwards.

    Leave a comment:


  • A.K. Boomer
    replied
    No doubt when it comes to low volts (meaning 12) our protection is our skin, sand your fingers down to the point where there so thin they are almost bleeding and wet them and I guarantee you will get a shock --- any doubts just touch a 9 volt to your tongue... 3 volts less and it will blast you into oblivion lol

    Leave a comment:


  • Jim Caudill
    replied
    This is a very interesting topic for me. Many years ago I read an article that I believe was in Readers Digest. I seem to remember that there was a fraternity at a Pennsylvania college that had a task that was part of their initiation/hazing ritual. They would have the pledges jump off a diving board into a pool and then when they climbed out, touch their fingers (opposite hands) to the terminals of a 12 volt car battery. Most folks got a nasty shock, but one fella actually died. The pool chemicals would reduce the skin's normal resistivity and make them much more conductive. The poor fella that dies may have had some type of underlying cardiac arrhythmia or just plain more susceptible. I have searched several times over the years for this article but have never been able to find it. I would like to have a copy of it for my basic electricity class that I teach for aspiring amateur radio licensees.

    Leave a comment:


  • legendboy
    replied
    I took 100vdc 30A thru my left hand across my chest down to my right hand. Still here. Felt much different than ac. The dc was smooth and didn't want to let go. I had gravity on my side that time.

    Leave a comment:


  • boslab
    replied
    I read a thing about welding, in particular underwater welding, apparently you can get zapped in the close proximity to the weld by the “electrical field”, that’s how the article suggested, I can’t say that I know anything much about underwater welding does this seem plausible, could it current kill?, don’t know any underwater welders to ask
    mark

    Leave a comment:


  • jdunmyer
    replied
    The batteries in most EVs definitely present an electrocution hazard, they're generally 400 volts. Some of the newer, higher powered vehicles are 800 volts. They do have some safety features: orange cables, a contactor to disconnect the battery, some sort of disconnect switch/plug, and they're often/usually/always ungrounded, so one side must short to ground in order for the other side to be dangerous. (the only one that I'm sure of is the Chevy Bolt EV, it is a floating setup)

    I don't know about hybrid cars, but most plugable hybrids would probably be like full EVs.

    Just saw a car fire this morning, it was REALLY burning, huge plume of black smoke, but couldn't see what kind of vehicle it was.

    Leave a comment:


  • J Tiers
    replied
    You read that wrong.

    The batteries may or may not hurt you, but the folks from the company will hunt you down if you open it up. And they will know when and where it happened.......😁😉

    Leave a comment:


  • A.K. Boomer
    replied
    120 commercial grade nickle metal hydride D-cell batteries all ran in series...

    Click image for larger version  Name:	DSC05362.jpg Views:	0 Size:	59.1 KB ID:	1937589

    I tear into everything and anything I can get my hands on --- the only thing that I steer clear of is that triple propeller radioactive symbol --- count me out --- leave that to the ruskies...

    Leave a comment:


  • A.K. Boomer
    replied
    Originally posted by reggie_obe View Post
    While a 12v automotive type battery can't kill you, apparently Tesla batteries can and do.
    https://kelleyuustal.com/elon-musks-...davie-florida/
    Not just Tesla's --- even the pea shooter could do you in or give you a rough day,,,

    Take a look at this sticker, Iv torn lots of stuff apart that threatened my ass with "could kill you" --- have to admit when I got this thing in my garage and seen the variation in the description "WILL" instead of "Could" it definitely got my attention --- only about 160 volts but tons of amps behind it...

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    then on a side panel enough warnings to scare a priest;

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    But --- even though I could not find anything I liked on youtube on how to disable the "bomb" all's you have to do is take your time and look, and after removing said panel I knew I had it made,,,


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    Bomb defused ;

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    My first hybrid adventure and they are actually quite simple to work on and get to know, at a basic level anyways... They are meant to be taken apart and put back together - very user friendly that way - at least the first gen insight is designed great that way... but --- I would not want to have to hunt down a blown resistor like I did with my DRO because the computer power is probably X 100 or more... or deal with a real computer glitch elsewhere .... not my cup of tea... everything else ? confidence is pretty high now...


    Leave a comment:


  • PStechPaul
    replied
    I have a TENS unit, and I begin to get a tingling sensation at about 10 mA, and usually use 20-30 mA for therapeutic reasons. Of course, that was with conductive electrode pads on the bare skin. If the pad lifts up and makes contact on a small spot, it increases current density and can be painful, and possibly cause burns. I think the unit runs at about 300-500 volts, which would be about 10 watts maximum. With current regulation, voltage will drop with skin resistance. 400 volts and 25 mA would be 16kOhms.

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  • SteveF
    replied
    Originally posted by A.K. Boomer View Post
    Volt's are what can stop (or re-start) your heart,,, as a mechanic holding on to ground with one hand and getting blasted in the other hand with 45,000 ignition volts and the path going right through the chest is not a good thing and yeah guys have died that way,,,
    Been there. Many years ago I was in the student auto shop tweaking the timing on my Mustang and grabbed the top of the distributor to turn it. Apparently old spark plug wire jackets do not insulate as well as new ones.

    Steve

    Leave a comment:


  • reggie_obe
    replied
    While a 12v automotive type battery can't kill you, apparently Tesla batteries can and do.
    https://kelleyuustal.com/elon-musks-...davie-florida/

    Leave a comment:

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