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Thread: Service neutral bonding location

  1. #21
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    Quote Originally Posted by Dale001289 View Post
    Whether to the earth or to the grid, fault path will seek all resistances - but back to the Xfmr (via the GEC) will be the least resistance path for solidly grounded Wye systems which is usually around 1 ohm or less. If you have a High Resistance Ground on the Delta-Wye Xfmr that's a different story.
    Not true.

    JAP>

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    True. Fault that goes into the ground must come out. It does not 'disperse' into the unknown earth.

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    Quote Originally Posted by Dale001289 View Post
    Whether to the earth or to the grid, fault path will seek all resistances - but back to the Xfmr (via the GEC) will be the least resistance path for solidly grounded Wye systems which is usually around 1 ohm or less. If you have a High Resistance Ground on the Delta-Wye Xfmr that's a different story.
    The GEC is important for reasons I won't go into here. But the EGC is what's really needed to clear a ground fault in a timely manner. So I disagree with your statement "but back to the Xfmr (via the GEC)." Ground fault current gets back to the xfmr primarily via neutral bonded to the EGC.

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    Quote Originally Posted by kmh View Post
    The GEC is important for reasons I won't go into here. But the EGC is what's really needed to clear a ground fault in a timely manner. So I disagree with your statement "but back to the Xfmr (via the GEC)." Ground fault current gets back to the xfmr primarily via neutral bonded to the EGC.

    If a fault occurs within the circuit, on the conduit or at the end device, it will travel via the neutral/EGC back to Xfmr - this represents the vast majority of faults--But when a fault hits the earth or grid remote from the EGC, it wont simply disappear into the earth - it will go back to the Xfmr.

  5. #25
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    Quote Originally Posted by Dale001289 View Post
    If a fault occurs within the circuit, on the conduit or at the end device, it will travel via the neutral/EGC back to Xfmr - this represents the vast majority of faults--But when a fault hits the earth or grid remote from the EGC, it wont simply disappear into the earth - it will go back to the Xfmr.
    Hopefully everyone in this forum realizes current does not just disappear into the earth.

  6. #26
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    Quote Originally Posted by Dale001289 View Post
    If a fault occurs within the circuit, on the conduit or at the end device, it will travel via the neutral/EGC back to Xfmr - this represents the vast majority of faults--But when a fault hits the earth or grid remote from the EGC, it wont simply disappear into the earth - it will go back to the Xfmr.
    When a fault occurs to normally non current carrying paths that are conductive, that current travels via the EGC back to the Grounded Conductor at the transformer if wired correctly, and yes, this represents one type of fault condition.

    Again. A lightning strike is not a fault.

    I've never seen a transformer or overcurrent protection device ahead of a lightning strike....... have you?

    Yes, a lightning strike does in fact simply disappear into the earth.
    You can't stop a lightning strike by any amount of ground rods or grids.

    If what you were saying were true, about a lightning strike traveling back up the GEC to the Grounded Conductor on a transformer in close proximity, lightning would destroy a ton of transformers each time one decided to strike the earth.

    That's simply not the case.

    JAP>

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    Quote Originally Posted by Dale001289 View Post
    True. Fault that goes into the ground must come out. It does not 'disperse' into the unknown earth.
    Where does it come out at?

    If a strike occurs in Colorado on a stormy day, does it come back up out of the ground in China and jump back up into the sky on a perfectly beautiful day ?

    JAP>

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    Quote Originally Posted by kmh View Post
    Hopefully everyone in this forum realizes current does not just disappear into the earth.
    Where does it go?

    So a lightning strike that hits the earth comes back up out of the ground,goes back up all of our Grounding electrode conductors to the Neutral point of all of our transformers, and that's what stops it?

    I think not.

    JAP>

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    Quote Originally Posted by jap View Post
    Where does it come out at?

    If a strike occurs in Colorado on a stormy day, does it come back up out of the ground in China and jump back up into the sky on a perfectly beautiful day ?

    JAP>
    I used to think lightning would dissipate into the earth too - but it doesn't work that way. It will seek a path to come out of the earth - it seeks ALL resistances, the sum of which equals the path of least resistance. That's why the people Hong Kong will never see a lightning strike in the US.

  10. #30
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    Quote Originally Posted by Dale001289 View Post
    I used to think lightning would dissipate into the earth too - but it doesn't work that way. It will seek a path to come out of the earth - it seeks ALL resistances, the sum of which equals the path of least resistance. That's why the people Hong Kong will never see a lightning strike in the US.
    Lightning is a whole different story than ground fault current. Charge a capacitor with DC voltage, then take the voltage connection away. Now jumper one side of the capacitor to the other. You'll get momentary current flow as the charges equalize. That's lightning. It's two opposite charges equalizing.

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