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Thread: Bonding metal parts of swimming pool cover

  1. #11
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    Quote Originally Posted by kwired View Post
    I think it would depend on how far from the pool it is before you can say it doesn't need bonded. You have two situations to be concerned about. 1 - typical rise in voltage that happens when there is fault from an ungrounded conductor. 2- smaller rise in voltage on EGC over true ground, which is main reason for EP bonding - you don't want to introduce "true ground" to a point within the area that requires equipotential bonding, that can leave potential voltage gradients that can be lethal to pool users. With EP bonding we don't care what true ground is, we want everything pool users can touch at same time to be at same potential regardless what voltage to true ground is.

    "Slip ring" the word you are trying to think of?

    Center pivot irrigation sometimes they call them "collector"


    You understand this well! It is 6” from the pool edge so well within the 5 ft required by code. It needs to be bonded by code and would be of best interest to bond it for the “what if’s”. A lot of people need to understand the difference of the right and wrong installation. They both work until something goes wrong

  2. #12
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    Quote Originally Posted by Forumrider2277 View Post
    You understand this well! It is 6” from the pool edge so well within the 5 ft required by code. It needs to be bonded by code and would be of best interest to bond it for the “what if’s”. A lot of people need to understand the difference of the right and wrong installation. They both work until something goes wrong
    have any theories of what the what if in this situation would be?

  3. #13
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    Quote Originally Posted by Forumrider2277 View Post
    You understand this well! It is 6” from the pool edge so well within the 5 ft required by code. It needs to be bonded by code and would be of best interest to bond it for the “what if’s”. A lot of people need to understand the difference of the right and wrong installation. They both work until something goes wrong
    Quote Originally Posted by Wire-Smith View Post
    have any theories of what the what if in this situation would be?
    What if's sort of don't matter, 680.26(B)(6) would require it to be bonded if it is electrically operated pool cover even if it is more than 5' from the pool.

    If not electrically operated then (B)(7) would require it to be bonded if within 5 feet of the pool.

    The what if's are same as they are for other objects - you want equipotential bonding between conductive objects in/near the pool to eliminate any possible voltage gradient between those objects. We don't care what voltage to ground is that much around a pool we care about what voltage between objects in the vicinity of pool users is, that is what causes shock/electrocution hazards.
    I live for today, I'm just a day behind.

  4. #14
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    Quote Originally Posted by kwired View Post
    What if's sort of don't matter, 680.26(B)(6) would require it to be bonded if it is electrically operated pool cover even if it is more than 5' from the pool.

    If not electrically operated then (B)(7) would require it to be bonded if within 5 feet of the pool.

    The what if's are same as they are for other objects - you want equipotential bonding between conductive objects in/near the pool to eliminate any possible voltage gradient between those objects. We don't care what voltage to ground is that much around a pool we care about what voltage between objects in the vicinity of pool users is, that is what causes shock/electrocution hazards.
    i agree its required by code, just wondering how it would become a hazard

  5. #15
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    Quote Originally Posted by Wire-Smith View Post
    i agree its required by code, just wondering how it would become a hazard
    Same way other objects in the same areas become a hazard. Bonding assures all bonded objects are at same potential. If you have a rise of 2-5 volts on your service neutral because of voltage drop, all your EGC's that are bonded to the neutral via the main bonding jumper also rise 2-5 volts. Bring that EGC to an item in pool vicinity and you have that same 2-5 volts to earth - pool user probably at very least feels something with this voltage, especially if they are immersed in the water when touching something with that potential. Now bond that item to everything else that is in or close to the pool and you raise the entire pool and everything around it that 2-5 volts, but to the user there is no potential between objects and that is what matters most. Entire pool and everything else bonded to it could be at 1000 volts to earth and users are still not subject to any voltage differences in what they can contact while in the pool - same reason nothing happens to birds sitting on a bare high voltage distribution line, you need to contact points of different potential to get shocked.
    I live for today, I'm just a day behind.

  6. #16
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    Quote Originally Posted by kwired View Post
    Same way other objects in the same areas become a hazard. Bonding assures all bonded objects are at same potential. If you have a rise of 2-5 volts on your service neutral because of voltage drop, all your EGC's that are bonded to the neutral via the main bonding jumper also rise 2-5 volts. Bring that EGC to an item in pool vicinity and you have that same 2-5 volts to earth - pool user probably at very least feels something with this voltage, especially if they are immersed in the water when touching something with that potential. Now bond that item to everything else that is in or close to the pool and you raise the entire pool and everything around it that 2-5 volts, but to the user there is no potential between objects and that is what matters most. Entire pool and everything else bonded to it could be at 1000 volts to earth and users are still not subject to any voltage differences in what they can contact while in the pool - same reason nothing happens to birds sitting on a bare high voltage distribution line, you need to contact points of different potential to get shocked.
    in your scenario wouldn't that egc rise be taken care of at the cover motor which is bonded to the equipotential bonding system.

    the hazards i always thought of that were being prevented were; the one you cited and also say for instance something that is in contact with earth and the pool which would be a conduit for transient current. but with this cover i'm not seeing a potential hazard, what could likely energize it (the cover motor or egc) is bonded to the pool water and everything else, the stationary parts of the cover are also bonded.

    again i'm not arguing that its not required by code, just trying to think of the potential hazard.

    thanks

  7. #17
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    Quote Originally Posted by Wire-Smith View Post
    in your scenario wouldn't that egc rise be taken care of at the cover motor which is bonded to the equipotential bonding system.

    the hazards i always thought of that were being prevented were; the one you cited and also say for instance something that is in contact with earth and the pool which would be a conduit for transient current. but with this cover i'm not seeing a potential hazard, what could likely energize it (the cover motor or egc) is bonded to the pool water and everything else, the stationary parts of the cover are also bonded.

    again i'm not arguing that its not required by code, just trying to think of the potential hazard.

    thanks
    The EBS isn't intended to get rid of the EGC rise it is intended to equalize potential between all bonded objects. If you have a large metallic object that isn't bonded - how do you know it it will take on said EGC rise or take on earth potential? If the entire pool is sitting there at a few volts above "earth" and that object happens to take on earth potential the risk of shock increases.

    Bonding it assures it will be at the EBS potential.
    I live for today, I'm just a day behind.

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