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Thread: Neutral voltage

  1. #31
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    Feb 2013
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    Quote Originally Posted by cknight View Post
    even if the bond is bad wouldn't the NEV be the same on both sides of the pool? Or at least close. The east side and the water read the same. Disconnect the bond and everything reads the same. Usually the NEV is the same all the way around the pool right? At least in the earth. Probably overthinking this. What is safer? No bond connected back to pool pump and all at the same reading or bonding it and having 3 volts present.
    NEV will remain same if ground resistance is zero. In your case it is not so. So you see different NEV's at different measurement points.You cannot dispense with bonding. It is a code violation. Apparently, with bonding you are getting shocked. The solution may be as I suggested earlier: Provide (additional) loop with a metal strip around the pool bonding all the nearby metal objects.

  2. #32
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    Quote Originally Posted by cknight View Post
    even if the bond is bad wouldn't the NEV be the same on both sides of the pool? Or at least close. The east side and the water read the same. Disconnect the bond and everything reads the same. Usually the NEV is the same all the way around the pool right? At least in the earth. Probably overthinking this. What is safer? No bond connected back to pool pump and all at the same reading or bonding it and having 3 volts present.
    The east side and the water appear to both be at "ground" potential. Some point. They either are not bonded or some point in bonding between those and the other items has failed. You want everything at same potential - hence the reason for all the bonding. but you must also bring EGC to pool pump or other electrical equipment in the vicinity - that introduces any rise in voltage from the service grounded conductor (which is normal to have low levels of rise on it because of voltage drop when it is carrying current) If everything is bonded well, you won't measure that voltage in the pool vicinity, you will measure it to ground references placed away from the pool area though. If you do measure it in the pool area one item is at ground potential and the other is at the equipotential bonding system potential.

    Again you are not "grounding" objects in the pool area, you are "bonding" them together so there isn't any potential between them.
    I live for today, I'm just a day behind.

  3. #33
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    Jan 2008
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    Quote Originally Posted by kwired View Post
    I agree, but isn't stray voltage only "stray" until you know what is causing it?

    Most of what people call "stray voltage" on a neutral is just results of voltage drop somewhere on that MGN, cause might be from primary current, might be from secondary current - either way there is a rise in voltage to "ground" when there is voltage drop across an otherwise grounded conductor, and if current is flowing there is some voltage drop across that conductor.
    Stray voltage is a potential that should not exist during normal equipment or system operations. The 3 volt NEV may be completely normal but we do not know. I would call 10 volts abnormal under most conditions. 3 volts is not so rare.

    Normal NEV is, by definition, not stray voltage.
    BB+/BB=?

  4. #34
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    Quote Originally Posted by cknight View Post
    even if the bond is bad wouldn't the NEV be the same on both sides of the pool? Or at least close. The east side and the water read the same. Disconnect the bond and everything reads the same. Usually the NEV is the same all the way around the pool right? At least in the earth. Probably overthinking this. What is safer? No bond connected back to pool pump and all at the same reading or bonding it and having 3 volts present.
    The NEV will be the same on both sides if you have a good bond between both sides.

    It is safer with a bond and 3 volts all around.
    BB+/BB=?

  5. #35
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    Don't think I worded that correctly. I meant the NEV in the earth. Not the concrete. The concrete is only 6' around the pool, then just dirt. I would think the NEV would be the same in the dirt if that's what it was. Disconnect the bond and it's not there in the earth.

  6. #36
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    I am assuming "NEV" means neutral to earth voltage.

    Earth is earth, the pool and everything that is supposed to be bonded to it very well may be different potential then earth - I keep trying to stress this point - it is the reason equipotential bonding is necessary for safety of users of the pool. We don't care what NEV is we care what potential is between objects in and around the pool. The fact that the EGC of pool pump and any other electrical items involved is also connected to the service neutral means the pool and entire EPB system will be at same potential as service neutral (if EPB is done correctly and has no holes in it)

    The fact OP has voltage between items that should be bonded together means there is a failure of bonding somewhere. Anything that is at same potential as "remote earth" is what isn't bonded to the EPB system.
    I live for today, I'm just a day behind.

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