I almost caused serious injury to myself

Discussion in 'General Electronics Chat' started by entity72, Dec 18, 2013.

  1. entity72

    Thread Starter New Member

    Dec 18, 2013
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    This just happened about 5 minutes ago. I had just bought a pair of 72 watt bulbs and one of them would not work. So, I looked at the contacts on the '3 bulb tree' (you know, one of those lightstands that has 3 adjustable mini lamp shades) and the one in the middle seemed to be recessed in compared to the other two.

    This is where my carelessness came into play. I was confident that I switched off that middle one and decided to use the pliers in my Swiss Army knife to pry it up a bit. The instant I touched the contact with the pliers it flashed an extremely bright light and made a very loud pop. It blew off a small bit of the tip of the pliers.

    Scared me half to death and immediately I felt incredibly lucky and flat out dumb.

    My question is how seriously could this have injured me? What stopped me from being zapped? I didn't feel a thing. I know my hand gripped the steel in between the plastic outer casings of the Swiss Army knife...

    I feel incredibly lucky and stupid. One instance of carelessness can seriously wreck you. This just happend minutes ago and immediately went to google an electronics forum. I'm still a bit shaken.
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    The hazard here was not that you get shocked, but that a piece of molten metal might have blinded you (if you weren't wearing glasses).

    You didn't post your location. Are you in the EU or the US?

    Is this a screw in-candleabra lamp or a bi-pin or what?
     
    Last edited: Dec 18, 2013
  3. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    How serious? You may have killed yourself, that is how serious.

    Toasters toast about 1,000 people a year.

    What saved you? The national electric code. The hot (dangerous) spot is burried in the bottom of the socket, surrounded by a ring of (safe) neutral. Your knife is likely to touch the large outer ring before it touches the inner tab so it keeps the flow of current within the knife and out of your body until the breaker trips or a wire burns open.

    Even if you nail the inner tab directly you still need to be well grounded, and free standing in sneakers can save your ass.

    ALWAYS unplug any device before you work on it. NEVER assume the switch is protecting you.
     
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    ALWAYS unplug it..
    ALWAYS use only 1 hand (even when unplugged...some devices carry enough "leftover" energy to do damage/death)
    ALWAYS use insulated tools.. (again even when unplugged)
    ALWAYS wear shoes and don't stand in water,etc..

    Had you been grabbing the base of the lamp with the other hand last year might have been the last Christmas you see..

    The worst is when electricity goes in one side of your body and out another.. hence the one hand and shoes..

    That swiss army knife saved your life...
     
    SgtWookie, dball387 and Brownout like this.
  5. tindel

    Active Member

    Sep 16, 2012
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    The one hand in your pocket trick only works if the power supply is isolated from earth ground.... with most light fixtures, this is not the case. It is good practice to still try to only use one hand though.

    I suspect that when you used your swiss army knife that a very high current flowed directly to the shield ground of the light fixture (hence the flash and sound). This current loaded the circuit enough to drop the voltage so that it was low with respect to the earth surface you were standing on. You probably did get some residual current thru your body.

    I have had to pull the hot pin further out of the light socket before as well. I usually use a zip-tie bent in the shape of a 'U' and pull up gently.
     
  6. inwo

    Well-Known Member

    Nov 7, 2013
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    It's incredibly difficult to get seriously injured working on 120v live circuits. (230 not so much)
    Yet as in the above post, 1000's do. (I'll look it up)

    Most injuries I suspect are from the arc flash and recoil.

    Being in a position of ground contact and no escape is the killer. IMO
    Such as in bathtub, under a car, laying on a conductive surface, or having part of body in contact with ground potential. ie. Refrigerator or sink.

    If you were in a dry area. No other conducting contact with body, except pliers. The only injuries would be, as mentioned above, from arc flash and flying hot metal.

    As a lifelong electrician, experienced with working on live circuits, I seem to have an innate perception of my exposed body parts.:D
     
  7. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    That's why I used my finger when I was prying on a live bulb socket.... seriously.

    Luckily, 115VAC isn't lethal to most people.... at least in never has been to me.
     
  8. Austin Clark

    Member

    Dec 28, 2011
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    When I was little I accidentally touched the hot terminal in a light socket directly with my hands. I definitely felt it, but it didn't feel super deadly, though I was probably touching the neutral with another part of that same arm and likely didn't get a strong jolt through my chest.
     
  9. inwo

    Well-Known Member

    Nov 7, 2013
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    I have a device to demonstrate the effects of 120vac.
    Only difference is it's at 30hz which is a more pleasant sensation.
     
  10. #12

    Expert

    Nov 30, 2010
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    Just yesterday a guy posted that he worked as an electrician and was taught to leave the hot wire hot and put the switch in the ground side of the circuit. That will get you even if the switch is off.:eek:

    As for the arc flash and reaction, yes. Once upon a time a spark jumped in a circuit breaker box and I came out of there so fast I would have run my head right into a wall if my helper hadn't caught me as I went by. (You never get over working on 30,000 volts.)
     
  11. dmshropshire

    Member

    Dec 1, 2013
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    ^^ Bottom line. I always check the circuit with a meter as well before I dig into high voltage. Its just worth double checking. Cant unplug it? Cut the breaker (Lock out if needed). Sure, this is not always ideal for people who work with it everyday, being a low voltage tech I get over paranoid about high voltage.

    FYI - DC Vol 1 Chapter three is a great read. No matter how experienced I think you can take something from it. If not, be reminded of something.
    http://www.allaboutcircuits.com/vol_1/chpt_3/1.html
     
  12. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Inwo,

    You are sending mixed messages! In this post you say it is INCREDIBLY DIFFICULT, in the Nuts & Volts post you (rightfully) claim a 120 volt lamp is a safety hazard. Why would you make a big deal about that story when getting injured on 120 v is "incredibly difficult".

    Which is it?
     
  13. wayneh

    Expert

    Sep 9, 2010
    12,103
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    YET :eek:

    In the spirit of the season: One of the more memorable shocks I ever got was plugging one string of Christmas lights into another. I was cold, working in wet falling snow. The plug wasn't going in easily so I had to push quite hard. My cold wet fingers slipped off the plastic back of the plug and smack onto the live metal prongs. I fell (jumped?) back and, next I knew, was staring up at the sky. I was fine, but you don't forget that 60Hz dance.
     
  14. wayneh

    Expert

    Sep 9, 2010
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    I get your point but that's a poor choice of words. Someone with a good respect for the danger - and therefore not standing in salt water in bare feet, for instance - is unlikely to do something stupid enough to suffer serious injury. But it's not "difficult" to get injured. Climb in the tub with your toaster. Done.
     
  15. entity72

    Thread Starter New Member

    Dec 18, 2013
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    Thanks for the responses and thanks for leaving any real harsh overtones out. I know it would've been real easy to scold me in a bad way so I appreciate it all the more considering that I"m still down on myself for being that careless... and I'll just go ahead and admit it, "lazy".

    I could've and ought to have just unplugged the damn thing but, you know, the plug wraps around my mini-dresser drawer and snakes behind my desk towards the corner outlet where the lamp is the only device plugged into it. The last time I saw that outlet was when I plugged the lamp into it.

    MikeML, I'm in the US.

    The mini pliers are scorched and on a second and closer look there appears to be an even bigger chunk of steel missing than I previously thought.


    I was wearing sneakers and I did have only my right hand in contact at that instant. I was sure to grab the lamp post with my left hand as it sits on a somewhat wobbly stand and I would've needed to hold the post to keep it still so I could pry the contact out. As luck would have it, I touched the contact before I grabbed with my left hand.

    Had I grabbed the post with my left hand first and then made contact with my SAK would my sneakers have made any difference here?

    Anyhow, I don't like what happened. I've reflected on this a few times today and I just shake my head. The only way I can get over this is to compensate by educating myself and vow never to be that careless again.

    So, it looks like I'll be hanging around. I did read #12's "Ohm's Law for Noobies" before I went to bed last night. That made me feel a bit better.
     
    Last edited: Dec 18, 2013
  16. inwo

    Well-Known Member

    Nov 7, 2013
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    Point taken. :(
    I guess I don't have enough imagination for the things people do.

    Difficult is a bad choice of words.
    People get killed every day.

    Have not figured out a way to let a toaster kill me yet. (in the kitchen)

    But hey, it would not be difficult if making breakfast in the tub.:)
     
  17. inwo

    Well-Known Member

    Nov 7, 2013
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    Now we may have to split this thread, but my worst shock:

    As a teenager we would often show off with the 7500v neon sign in the window behind our booth.

    Drawing an arc to a finger and quickly touching it before it burned thru the skin.

    On a dare, the next step involved the other hand and the other terminal.
    Don't remember the arc. Knocked me out cold.

    And of course, you are right, not incredibly difficult.
    Just incredibly stupid.
    Indoor nst's are limited to ~30ma. After that I new my limit!
     
  18. entity72

    Thread Starter New Member

    Dec 18, 2013
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    ^^^^
    Hey, go ahead and share. After reading a couple of "shock" anecdotes, I don't feel quite the goof I did before. Still feel goofy... just a little less.
     
  19. wayneh

    Expert

    Sep 9, 2010
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    Part of the aging process, if you're paying attention, is learning all the myriad ways you can get hurt or killed. Whenever you are lucky enough to walk away, just be glad and tell yourself, "I shall not pass this way again."
     
  20. Metalmann

    Active Member

    Dec 8, 2012
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    Up until a few years ago, I worked on live 120-220 circuits.
    After flashing inside a box with a big screwdriver, I figured it was time to stop that nonsense.:D
     
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