Is 440V enough to cause arc flash burn on our body?Or is it the current passing through that does?

Discussion in 'General Electronics Chat' started by Rahulk70, Apr 29, 2017.

  1. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Got electrocuted from a much smaller industrial control transformer about 0.150kVA at 440V. I wanted to test if it was working and plugged it into a UPS 120VAC 300W just as safety to reduce current(mostly an explosion in case I accidently shorted any leads). I was careless didn't wear safety gloves or any protection and my left arm accidently touched the 440V output when the transformer was powered from the UPS and it was the nastiest shock I've ever got. My hand just went numb and was kinda paralysed for few minutes and the portion where my fingers had touched there was two charred spots, kinda burned smell. I saw a small blue-violet-pinkish arc at the two tips of my finger. Was lucky it wasn't the mains or else I wouldn't be typing this now. Proper safety is a much in HIGH VOLTAGE! or else we pay the price for our ignorance.
     
  2. Reloadron

    Distinguished Member

    Jan 15, 2015
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    480 Volt 3 Phase Arc Flash.

    I will vote that a 440 or 480 volt arc flash can most definitely burn as long as adequate current is there. I have seen molten metal fly on a few occasions. A 440 or 480 source voltage will also produce a shocking experience even with low current as you discovered. High voltage here in the US is defined as being above 600 Volts. That being in accordance with OSHA 1910.269, NESC 2012 and NFPA 70E regulations and guidelines.

    Ron
     
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  3. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    Even low voltage DC can be dangerous if enough current is available
    I witnessed a good quality chrome moly alloy wrench turn bright white incandescent and Poof! into a sparkling explosion of molten metal mist. No one got hurt but lesson learned.
    (48 volt backup battery bank in a phone office)
     
  4. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    It must be those high current Lead Acid or Ni-Fe batteries capable of giving 100s to 1000s of amps I guess.
     
  5. Tonyr1084

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    Sep 24, 2015
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    I saw the aftermath of what happened when a nut fell off a bolt in a 480 electrical panel and made contact between the 480 and ground. The door was blown off and it was a good thing nobody was standing in front of the door when it went flying off at near supersonic speed. The door (small panel) ended up almost 200 feet down the assembly bay in a steel fabrication shop. Nobody was hurt.

    Is this conversation even allowed on this web format? I thought discussion of mains was a prohibitive topic. Well, I suppose if you're asking about what effects it can have - I believe a good solid arc flash CAN burn skin. But the instance you spoke of you got a current burn. I also saw pictures of a guy who was wearing a wedding ring and accidentally grabbed a live power line on an aircraft while leaning against the bulkhead. Burned his arm pretty badly. I think someone said the ring welded to the wire, though I have difficulty accepting that part of the story. Still, messing with 440 or 480 if you're not trained properly - I'd suggest you leave that to someone who KNOWS the answers to your question and stop running the risk of injury or death.
     
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  6. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Hi,
    Yes I think discussion of mains is prohibited. But I asked this question specifically to know the cause of burn. Well the incident already ocurred due to my carelessness. No protective gear or gloves. I guess it was the limited current since I used a small UPS only that saved me.
     
  7. tcmtech

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    Nov 4, 2013
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    No. we can talk about mains power all we want. We just cant talk about hooking a LED up to it because that will get someone killed. :rolleyes:
     
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  8. dl324

    AAC Fanatic!

    Mar 30, 2015
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    Rahulk70 likes this.
  9. tcmtech

    Distinguished Member

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    Same here. It's rather like saying you got shot and killed yet here you are still alive only with a new and likely painful hole in you some place. :rolleyes:
     
  10. bertus

    Administrator

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  11. WBahn

    Moderator

    Mar 31, 2012
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    In asking if 440 V can cause a flash burn on the human body, consider whether a 24 V arc welder cause a flash burn on the human body?
     
  12. dl324

    AAC Fanatic!

    Mar 30, 2015
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    I saw the results of someone shorting a 5V 100A power supply with his metal watch band. It wasn't a pretty sight. He learned that the policy of not wearing metal jewelry while working wasn't a joke...
     
  13. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You just need to watch a Plasma torch in action, 200vdc with a arc through ionized air cutting 1/2" steel plate.:cool:
    Max.
     
  14. Bernard

    Expert

    Aug 7, 2008
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    All it takes is about 50 mA hand to foot,etc. & curtains.
     
  15. boatsman

    AAC Fanatic!

    Jan 17, 2008
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    @Bernard : All it takes is about 50 mA hand to foot etc. & curtains.

    I've got a rod in my pocket and it's curtains for you - it's a curtain rod!
     
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  16. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Yes Sir, I've always followed the handbook.But I became careless thinking that the power input to the transformer in this case was just a mere 120VAC 300W UPS supply, nothing that would cause an explosion or anything like on mains. I learned my lesson the hard way. :(

    luckily for me the entry was my left hand middle finger and the other exit was the pinky finger. Had it passed through my heart....

    Using the input as UPS actually made me lucky.
     
    Last edited: Apr 30, 2017
  17. WBahn

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    Mar 31, 2012
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    Think about what you've just said, "I've always followed the handbook," followed immediately by the admission that you don't always follow the handbook. But I suspect that almost everyone would have to make that same admission to one degree or another and, as you say, you learned a valuable lesson the hard way.
     
  18. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Yes. You are right. Maybe I should correct it to "I had followed it till that day".
     
    Last edited: Apr 30, 2017
  19. DickCappels

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    Aug 21, 2008
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    Watching an electrician installing 440V service in our lab he told me that 440 (60 Hz) is the most dangerous voltage he's worked on. At lower voltages the potential (literal term :) to shock is lower and at higher voltages sometimes the victim is "thrown off" and out of contact, but at 440V you just can't let go.
     
  20. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    No. Using the UPS made you complacent. It gave you a false sense of security.

    Would you feel comfortable sticking your fingers into the output of that inverter? I should hope not.

    So why think it was safe to touch the output of a step UP transformer?

    All using that inverter did for you was to slightly limit the fault current thru a dead short over using a wall outlet.

    Either one has the power to kill you.

    As far as batteries go, any car mechanic you ask will have horror stories about a simple car battery melting tools carelessly pressed against them. Even a 9 volt battery can burn your entire house down:

     
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