Free 186 More Best Homemade Tools eBook:  
Get 2,000+ tool plans, full site access, and more.

User Tag List

Page 3 of 3 FirstFirst 1 2 3
Results 21 to 26 of 26

Thread: Man saves friend from electrocution - GIF

  1. #21
    Supporting Member marksbug's Avatar
    Join Date
    Apr 2016
    Posts
    1,905
    Thanks
    737
    Thanked 372 Times in 298 Posts
    foolishness??? was one named tommy? more like stupid is as stupid does.

    186 More Best Homemade Tools eBook

  2. #22
    Supporting Member tonyfoale's Avatar
    Join Date
    Nov 2016
    Location
    Spain
    Posts
    1,576
    Thanks
    696
    Thanked 2,654 Times in 713 Posts

    tonyfoale's Tools
    When I was a kid my interest was electronics. I had a younger brother whom I was never on very friendly terms with. I used to charge electrolytic capacitors, or condensors as they were called back then, up to around 300 V (typical HT value for radios then) and throw them to my brother shouting "catch".

    2000 Tool Plans

  3. #23
    Supporting Member tonyfoale's Avatar
    Join Date
    Nov 2016
    Location
    Spain
    Posts
    1,576
    Thanks
    696
    Thanked 2,654 Times in 713 Posts

    tonyfoale's Tools
    Quote Originally Posted by Frank S View Post
    I have been on the receiving end of nearly being electrocuted its no fun. Sweaty gloves aluminum ladder 16 feet off the ground ac welder and some how managed to break the insulation off the handle of the stinger which immediately managed to find a hole in one of my gloves luckily the setting on the welder was only for 90 amps.
    when it caught hold of me all I could focus on was to make sure I tightened my grip on the ladder with my left hand and yell out shut it off shut it off several times. the jolting from the current passing from one hand through the other made my whole buddy jerk finally my jerking movements dislodged the stinger from my right hand and the pathway for the current was broken when I dropped the stinger I grabbed another ladder rung with my right hand and just hung on for a few moments then managed to climb down with out falling but it was several minutes before I could talk coherently just broken or clipped words and part sentences.
    they always say its not the volts but the amps that get you well 90 amps at 27Volts AC hurts and could easily kill
    Whilst being electrocuted one's thoughts do not always focus on ohm's law but it still applies. 27 V driving 90 A requires a resistance of no more than 27/90 = 0.3 ohms which is way to low for body resistance. Internal body resistance is in the order of a few 100s of ohms but unless you have broken skin at the contact points the skin resistance will be many times higher. For example dry skin will be up around 100 kohms. So taking a worst case open wound shock of 100 ohms the current from 27 V will only be 27/100 = 270 mA far removed from your 90 A, but way more than enough to do you very serious damage. Only very few mA is enough to be dangerous. Take the case of dry hands, there will be two skin contacts but lets just use one at 100,000 kohms the current from 27 V then will be 0.27 mA which is unlikely to be noticed.
    It does not matter what current the power source is capable of supplying, what matters is what current the voltage can force through your body and those two things are very different.

  4. #24
    Supporting Member Frank S's Avatar
    Join Date
    Aug 2015
    Location
    Peacock TX
    Posts
    11,258
    Thanks
    2,003
    Thanked 8,822 Times in 4,224 Posts

    Frank S's Tools
    Quote Originally Posted by tonyfoale View Post
    Whilst being electrocuted one's thoughts do not always focus on ohm's law but it still applies. 27 V driving 90 A requires a resistance of no more than 27/90 = 0.3 ohms which is way to low for body resistance. Internal body resistance is in the order of a few 100s of ohms but unless you have broken skin at the contact points the skin resistance will be many times higher. For example dry skin will be up around 100 kohms. So taking a worst case open wound shock of 100 ohms the current from 27 V will only be 27/100 = 270 mA far removed from your 90 A, but way more than enough to do you very serious damage. Only very few mA is enough to be dangerous. Take the case of dry hands, there will be two skin contacts but lets just use one at 100,000 kohms the current from 27 V then will be 0.27 mA which is unlikely to be noticed.
    It does not matter what current the power source is capable of supplying, what matters is what current the voltage can force through your body and those two things are very different.
    Trust me, when there is a current passing through your body from one hand to the other that is high enough to cause involuntary muscle contractions while standing on a ladder you are thinking of only 2 things first is how can I break the contact and 2nd not falling off the stupid ladder thinking that falling off the ladder may even be the best choice. The longer you are in the situation the greater the amount of moisture your body is going to produce through your hands until if someone were to put an ohm meter in circuit it would show a near perfect continuity at which time it is all over. I should have never been on that aluminum ladder in the first place because I had a wooden ladder, I could have been using but the thing was so heavy it took two people to stand it up.
    Never try to tell me it can't be done
    When I have to paint I use KBS products

  5. #25
    Supporting Member tonyfoale's Avatar
    Join Date
    Nov 2016
    Location
    Spain
    Posts
    1,576
    Thanks
    696
    Thanked 2,654 Times in 713 Posts

    tonyfoale's Tools
    Quote Originally Posted by Frank S View Post
    Trust me, when there is a current passing through your body from one hand to the other that is high enough to cause involuntary muscle contractions while standing on a ladder you are thinking of only 2 things first is how can I break the contact and 2nd not falling off the stupid ladder thinking that falling off the ladder may even be the best choice. The longer you are in the situation the greater the amount of moisture your body is going to produce through your hands until if someone were to put an ohm meter in circuit it would show a near perfect continuity at which time it is all over. I should have never been on that aluminum ladder in the first place because I had a wooden ladder, I could have been using but the thing was so heavy it took two people to stand it up.
    That is all true except that your resistance does not drop to near zero. If someone put at ohm meter on you when sweating it would be measuring the resistance through the sweat in parallel with your body not through your body. You resistance will have dropped compared to the dry condition but not to near zero.
    I was only pointing out that just because the welder is set on 90 A does not mean that 90 A will be passing through your body. It only takes mAs to cause muscle contractions.

  6. #26
    Supporting Member Frank S's Avatar
    Join Date
    Aug 2015
    Location
    Peacock TX
    Posts
    11,258
    Thanks
    2,003
    Thanked 8,822 Times in 4,224 Posts

    Frank S's Tools
    Quote Originally Posted by tonyfoale View Post
    That is all true except that your resistance does not drop to near zero. If someone put at ohm meter on you when sweating it would be measuring the resistance through the sweat in parallel with your body not through your body. You resistance will have dropped compared to the dry condition but not to near zero.
    I was only pointing out that just because the welder is set on 90 A does not mean that 90 A will be passing through your body. It only takes mAs to cause muscle contractions.
    Yep If 90 amps were passing through it would have been 2 wires stuck in a hotdog then plugged into a wall socket. well, done in seconds. Even at that it wouldn't have been the 15 amps of the circuit, it would have been the length of the wires extending into the hot dog verses. circular diameter and the moisture content of the hot dog determining the amount of resistance. to account for how many mAs or full amps plus the total amount of seconds to boil the moisture cooking the hotdog.

    The longer I was completing the circuit the more accumulative I could feel the effects intensifying.



    186 More Best Homemade Tools eBook
    Never try to tell me it can't be done
    When I have to paint I use KBS products

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •