Lazy River Pool Pump Vault 680.12 & 680.13

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Colorado
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.

Pool Vault Detail 2.jpg Pool Vault Layout.jpg

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?
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
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
 

tom baker

First Chief Moderator
Staff member
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!
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
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...
 

kwired

Electron manager
Location
NE Nebraska
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.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
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
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
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.
 

kwired

Electron manager
Location
NE Nebraska
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.
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
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.
 

tom baker

First Chief Moderator
Staff member
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
 

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kwired

Electron manager
Location
NE Nebraska
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.
 

GeorgeB

ElectroHydraulics engineer (retired)
Location
Greenville SC
Occupation
Retired
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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