120V Source "phase-leg" Touching Indicator

Discussion in 'The Projects Forum' started by HighVoltage!, Jun 10, 2015.

  1. HighVoltage!

    Thread Starter Member

    Apr 28, 2014
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    Hello Everyone!
    I was wondering if there is a way to get multiple "light-up" configurations using a 120V power outlet source: Is there a way to branch off the hot leg/Neutral and get several different combinations as to know what leg touched what leg using some indication such as a light bulb (I would like to know up to 8 combinations)? I am trying to make this as small as possible. Any ideas?
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Not quite sure what you are after, detect which 120v side to neutral? Live to earth?
    Max.
     
  3. HighVoltage!

    Thread Starter Member

    Apr 28, 2014
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    An example: When Hot touches Nuetral I want a light bulb to light up, but with more combinations available. If I convert it to AC to DC, will my response time be as quick as AC alone?
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Live shorted to neutral should cause an imediate GFI trip, blown fuse, tripped breaker?
    Or are you saying you want an indicator to remain on after the trip has occured?
    Max
     
  5. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Connecting a light bulb between hot (line) and Neutral is how you make it light up (ps. its called a lamp);)
     
  6. HighVoltage!

    Thread Starter Member

    Apr 28, 2014
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    That is correct! What if there is a high resistive load light bulb inbetween? Wither way I am leaning towards AC to DC. But my concern is will it have a quick response?
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    If you want something that is retained after the short then you need a peak current indicator/current transformer etc, fed from a separate supply and stay latched until reset.
    Max.
     
  8. HighVoltage!

    Thread Starter Member

    Apr 28, 2014
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    That is a great idea. If I want several combinations of shorts, is there a way to use 120V supply for this thats including the cts?
     
  9. WBahn

    Moderator

    Mar 31, 2012
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    What do you mean by "several combinations of shorts"?
     
  10. HighVoltage!

    Thread Starter Member

    Apr 28, 2014
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    In other words hot leg one making contact with neutral, second hot leg making contact to neutral, hot one contact with hot 2
     
  11. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    But these are all normal provided that the current is not sufficient to trip a breaker or blow a fuse. You have to distinguish between the normal load current and a much higher fault current. The detection of the fault is that the fuse blew
     
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  12. HighVoltage!

    Thread Starter Member

    Apr 28, 2014
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    Is there anything in resetable form? So your saying I can tap into hit line and split it into 3 and use a fuse as an indication? Just trying to picture this.
     
  13. HighVoltage!

    Thread Starter Member

    Apr 28, 2014
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    Hot line
     
  14. WBahn

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    Mar 31, 2012
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    But if you have a 120V outlet, you only have one hot leg. So where is this second hot leg coming from?

    And what do you mean "making contact with neutral"? That's been asked before. If the hot makes contact with the neutral you will almost instantly blow something -- a GFCI, a breaker, a fuse, etc.. You then ask about if there was a high resistance bulb in the path. Well, if the hot is in contact with the neutral, then there IS not path in between, and if the bulb is in the path between them, then the hot is NOT in contact with the neutral.
     
  15. WBahn

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    Mar 31, 2012
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    Uh, yeah, it's called a circuit breaker.

    It is becoming pretty clear that you are no where near being qualified to be messing with this stuff until you learn a LOT more about the basics. Have no illusions, a 120V AC line has more than sufficient potential to kill you if you don't know what you are doing.
     
  16. HighVoltage!

    Thread Starter Member

    Apr 28, 2014
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    Im pretty aware of the dangers involved. I am just going to convert to DC via full rectification.
     
  17. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Why are you going to convert it to DC? 170VDC can kill as well as AC. Are you using an isolation transformer?

    I agree with WBahn.
     
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  18. HighVoltage!

    Thread Starter Member

    Apr 28, 2014
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    I am stepping it down to a safer DC voltage :)
     
  19. MaxHeadRoom

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    Jul 18, 2013
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    If you use something like the Honeywell CSDA current sonsor series, you can feed a low level circuit off of another source and set the current sensor into a comparator and latch of some kind.
    Max.
     
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