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Lazy River Pool Pump Vault 680.12 & 680.13

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    Lazy River Pool Pump Vault 680.12 & 680.13

    I am working on a commercial pool project where the pool designer has located below grade pump vaults (Roughly 6'x 3.5' x 32" deep) adjacent to and around a lazy river pool.

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    They have provided drains for the vaults in compliance with 680.12.

    They will separate the disconnect a minimum of 5'-0" from the pool.

    My concern is they are asking us to put a disconnect and the motor connections below the maximum water level in these vaults. With 12" supply and return lines running into these vaults if anything were to go wrong the vault could fill up with pool water and submerge the disconnect and motor connection and potentially electrify the pool water. As such this request does not feel prudent. However, I haven't found any code reference that outright prohibits it.

    The ultimate goal of NEC 680 seeks to keep people and water separated from electricity. It seems that it tries to keep electrical connections above the maximum water level to prevent the failure scenario described above.

    Thoughts?

    Opinions?

    #2
    All there is is 680.11:

    680.11 Equipment Rooms and Pits Electrical equipment shall not be installed in rooms or pits that do not have drainage that adequately prevents water accumulation during normal operation or filter maintenance.
    If a pit should fill up with water the motor and receptacle should be protected by a GFCI breaker that will cut power. Other than this if you are still concerned it becomes a design issue. Move the receptacles outside of the pits.

    -Hal

    Comment


      #3
      I have seen pump pits filled with water and the pump still running.
      Clean water is not a conductor, and a GFCI may not trip
      Consider a flood switch connected to a shut trip breaker
      Sump pumps and float switches, if used need to be checked frequently.

      Please check working clearances on the disconnect switch, does not seem to meet code.
      Make sure all conduit is arranged to drain, when I wired vaults I would enter with a LB, drill a drain hole, then go up with conduit.
      Or sometimes install a T conduit body with a drain at the bottom of the T and flex from the side to the device.

      At least you don't have a confined space!
      Moderator-Washington State
      Ancora Imparo

      Comment


        #4
        Originally posted by tom baker View Post
        I have seen pump pits filled with water and the pump still running.
        Clean water is not a conductor, and a GFCI may not trip
        Consider a flood switch connected to a shut trip breaker
        Sump pumps and float switches, if used need to be checked frequently.

        Please check working clearances on the disconnect switch, does not seem to meet code.
        Make sure all conduit is arranged to drain, when I wired vaults I would enter with a LB, drill a drain hole, then go up with conduit.
        Or sometimes install a T conduit body with a drain at the bottom of the T and flex from the side to the device.

        At least you don't have a confined space!
        Heh, if you think the water in a lazy river is clean, you've never been to one...
        __________________________________________________ ____________________________
        Many people are shocked when they discover I am not a good electrician...

        I'm in California, ergo I am still stuck on the 2014 NEC... We'll get around to the 2017 code in around 2021.

        Comment


          #5
          Originally posted by tom baker View Post
          I have seen pump pits filled with water and the pump still running.
          Clean water is not a conductor, and a GFCI may not trip
          Consider a flood switch connected to a shut trip breaker
          Sump pumps and float switches, if used need to be checked frequently.

          Please check working clearances on the disconnect switch, does not seem to meet code.
          Make sure all conduit is arranged to drain, when I wired vaults I would enter with a LB, drill a drain hole, then go up with conduit.
          Or sometimes install a T conduit body with a drain at the bottom of the T and flex from the side to the device.

          At least you don't have a confined space!
          Define clean water.

          Pure water doesn't conduct well at all, but not much water is that pure unless it was purified and then kept in a sealed container. Naturally occurring water or any purified water that has been exposed to other things will always have some minerals it has absorbed and that raises conductivity.
          I live for today, I'm just a day behind.

          Comment


            #6
            I would put the disconnect above ground on a post and bring the pump cable up and out of the pit into the bottom of it. Then use some clever landscaping to hide the disconnect.

            -Hal

            Comment


              #7
              Originally posted by kwired View Post
              Define clean water.

              Pure water doesn't conduct well at all, but not much water is that pure unless it was purified and then kept in a sealed container. Naturally occurring water or any purified water that has been exposed to other things will always have some minerals it has absorbed and that raises conductivity.
              Pool water is treated with chlorine, which makes it highly conductive.

              The way I understand it, some of the chlorine atoms (or maybe all of the chlorine atoms) looses an electron and become chlorine ions.

              These have a positive charge, and of course the electrons have a negative charge. Both are free to move through the water and will move and conduct electricity when there is a voltage present. Although the electrons are much lighter and more mobile, so most conduction is via the free electrons.

              Comment


                #8
                Originally posted by steve66 View Post
                Pool water is treated with chlorine, which makes it highly conductive.

                The way I understand it, some of the chlorine atoms (or maybe all of the chlorine atoms) looses an electron and become chlorine ions.

                These have a positive charge, and of course the electrons have a negative charge. Both are free to move through the water and will move and conduct electricity when there is a voltage present. Although the electrons are much lighter and more mobile, so most conduction is via the free electrons.
                So is it clean water or not?

                Certainly not pure water.
                I live for today, I'm just a day behind.

                Comment


                  #9
                  Originally posted by kwired View Post
                  So is it clean water or not?

                  Certainly not pure water.
                  Agreed - it won't be pure water.

                  But I'm not sure what that means for the original question. Its probably common to put these pumps in pits, conductive water or not.

                  Comment


                    #10
                    Example of clean water, related to this post
                    A small vault, about 3 ft sq x 2 ft deep, with a 2 hp pump,a water booster pump, filled with rainwater as roots clogged the drain.
                    The fuses blew. This was on a weekend, customers out of water
                    Choice was to pull the motor and have it baked in an oven by a motor shop , or replace fuses, start pump and let it dry itself out, nothing to loose.
                    Turned on and ran, dried out OK.
                    If dirty water, IE flood or sewage the motor would be replaced (not worth working on for a 2 hp) due to contamination.

                    At a Mike Holt Seminar, some one commented "water and electricity don't mix". Mikes comment was clean water is not a conductor. He takes a plug strip, puts in a water picture and proceeds to drink from it
                    Attached Files
                    Last edited by tom baker; 07-10-19, 07:13 PM.
                    Moderator-Washington State
                    Ancora Imparo

                    Comment


                      #11
                      Originally posted by tom baker View Post
                      Example of clean water, related to this post
                      A small vault, about 3 ft sq x 2 ft deep, with a 2 hp pump,a water booster pump, filled with rainwater as roots clogged the drain.
                      The fuses blew. This was on a weekend, customers out of water
                      Choice was to pull the motor and have it baked in an oven by a motor shop , or replace fuses, start pump and let it dry itself out, nothing to loose.
                      Turned on and ran, dried out OK.
                      If dirty water, IE flood or sewage the motor would be replaced (not worth working on for a 2 hp) due to contamination.

                      At a Mike Holt Seminar, some one commented "water and electricity don't mix". Mikes comment was clean water is not a conductor. He takes a plug strip, puts in a water picture and proceeds to drink from it
                      Tap water typically has minerals in it and is conductive. We have to presume plug strip was energized, but standing on a carpeted floor greatly lessens any risk. Might not want to try this on wet concrete on grade, worse yet while barefoot.
                      I live for today, I'm just a day behind.

                      Comment


                        #12
                        Yes, "pure" water is non-conductive. My first job out of engineering school was in a Duke Power (now Duke Energy) generating station. Generator stator (output) coils were hollow and water cooled. Units I worked with were at least 40MW up to 1.2GW. Generator voltage tended to be in the 18kV to 35kV range. Larger units (I don't remember any specifics) didn't have generator breakers or switches as the current was to high for then-current technology. They stepped it up to 100kV, 230kV, or 500kV and switched it there. We used ACB, OCB VCB, and SF6 breakers/switches.

                        Generator rotors (field coils and core losses) were hydrogen cooled with hydrogen between 0.5 psig (1920's vintage) to 60 psig (1970s vintage) with oil fed labyrinth shaft seals to keep the hydrogen in. Every seal had multiple sensors to confirm the H2 concentration was WELL away from combustible ranges.

                        Hard to believe it's been 45 years.

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