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

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  • #46
    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.


    • #47
      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.
      At the end of the project, there is a profound difference between spare parts and left over parts.

      Location: SF East Bay.


      • #48
        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.)


        • #49
          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.
          Illigitimi non Carborundum 😎
          9X49 Birmingham Mill, Reid Model 2C Grinder, 13x40 ENCO GH Lathe, 6X18 Craftsman lathe, Sherline CNC mill, Eastwood TIG200 AC/DC and lots of stuff from 30+ years in the trade and 15.5 in refinery unit operations. Now retired. El Paso, TX