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Thread: Do breakers ever get "weak"

  1. #11
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    Quote Originally Posted by electrofelon View Post
    Were they old or relatively new?

    Old ones but I have seen some not function right out of the box.
    They say I shot a man named Gray and took his wife to Italy
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    I can't help it if I'm lucky



  2. #12
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    Quote Originally Posted by pjones View Post
    Sorry, I’m having a hard time figuring this one out. What’s an FOP test?


    Sent from my iPhone using Tapatalk
    You need a fairly good meter with a mili volt range. Multipole breakers with the same load should have approximately the same VD across the Line 1 to Load 1, etc. 100mv or less.

    Zero volt drop would mean zero load to me.
    Tom
    TBLO

  3. #13
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    Anything that creates undesired heat within is going to increase the possibility of tripping on thermal, can even be heat that originates at a termination or bus connection and is conducted to interior of the unit.
    I live for today, I'm just a day behind.

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    Quote Originally Posted by kwired View Post
    Anything that creates undesired heat within is going to increase the possibility of tripping on thermal, can even be heat that originates at a termination or bus connection and is conducted to interior of the unit.
    I could see that, but what isn't clear to me is how the mag function would go bad to make it trip early.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

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    Quote Originally Posted by Dennis Alwon View Post
    Old ones but I have seen some not function right out of the box.
    I guess I am lucky. Can't ever remember getting a bad breaker out of the box, other than maybe one or two that wouldn't latch closed. Can't ever remember one being overly sensitive.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  6. #16
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    Quote Originally Posted by electrofelon View Post
    I could see that, but what isn't clear to me is how the mag function would go bad to make it trip early.
    I see mechanical wear being a bigger issue that may affect mag function, could make it trip easier or could make it need higher mag field to make it trip, depends on what/how an item wears out.
    I live for today, I'm just a day behind.

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    Quote Originally Posted by electrofelon View Post
    I could see that, but what isn't clear to me is how the mag function would go bad to make it trip early.
    That would more likely be from mechanical wear from being used daily as a switch rather than just age.

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    Quote Originally Posted by GoldDigger View Post
    That would more likely be from mechanical wear from being used daily as a switch rather than just age.

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    And could make it trip at higher or lower fault current depending on wear conditions I would think, or at very least affect clearing time compared to when it was new.
    I live for today, I'm just a day behind.

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    Too Many....

    Quote Originally Posted by LarryFine View Post
    FOP = Fall Of Potential

    It means measuring the voltage between the line and load terminal of one pole at a time. You're looking for voltage drop where there shouldn't be any. In theory, there should be zero volts across a closed switch or breaker.

    I would check the line current with a clamp-on ammeter.
    There are TOO MANY, WAY TOO MANY ACRONYMS, and they are becoming bothersome for this reason. There are other aspects about them which make them even more distasteful that there is no need to go into. Some of the exact same ones cross over into completely different trades and mean different things.
    There needs to be as master list on the forum possibly.
    Microwave Radiation Dangers should be openly discussed

  10. #20
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    Quote Originally Posted by StarCat View Post
    There are TOO MANY, WAY TOO MANY ACRONYMS, and they are becoming bothersome for this reason. There are other aspects about them which make them even more distasteful that there is no need to go into. Some of the exact same ones cross over into completely different trades and mean different things.
    There needs to be as master list on the forum possibly.
    Good point, especially since I would not use FOP to describe what I would call a voltage drop test across the terminals of the breaker.

    When I hear Fall of Potential used, I pretty much instantly think about grounding electrode resistance tests.
    Cheers and Stay Safe,

    Marky the Sparky

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