Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 13 of 13

Thread: Bonding Mystery - Pool Light

  1. Back To Top    #1

    ChuckDavis's Avatar
    Join Date
    Aug 2010
    Location
    Durham, NC
    Posts
    73

    Bonding Mystery - Pool Light

    I have an in-ground concrete pool (epoxy paint finish) with an Amerlite underwater light. The chrome bezel continuously turns black. The tarnish can be scrubbed off, but always returns. (There is also an ongoing, low-intensity battle with minor metal stains, with no known source for the metal.)

    The tarnish probably indicates a bonding problem, but.................

    There is a bond wire from the light niche to the bonding lug on the pump. The bond wire is #8 *stranded*, however. The wire connects to the inside of the niche and runs up the conduit with the power cord. The attachment of the bond wire to the niche is slathered in some sort of caulk. Using a wire nut in the J-box, the stranded bond wire is connected to another run of #8 stranded wire that goes back to the pump. It is a 30-40 foot run from the niche to the pump.

    While the pool was partially drained I used a VOM to test, and there is continuity from the niche to the bonding lug on the pump. I connected my test wire to the screw hole where the screw holding the bezel in place is inserted, so I can assume that there is continuity from the bezel to the pump.

    There are two other bond wires (also #8 stranded) connected to the bonding lug on the pump. One comes from the heat pump. The other comes from the concrete pool deck, with a bond wire from the rebar in a hot tub slab that I poured spliced into it. I have no idea of the quality or condition of the bond in the concrete pool deck.

    The only real weirdness that I can see is the bond wire connection inside the niche, possibly in contact with the water if the caulking has failed. Since the goal of bonding is to keep everything, including/especially the water, at the same potential, I'm not sure this is a problem.

    Does anybody have any ideas or suggestions on how to diagnose or fix what probably is some sort of current flow causing the tarnish on the light bezel?

    Thanks.
    15,000 gallon IGP, epoxy surface, waterfall, borates (!), not closed in winter
    SuperPump with 2.4 THP EcoTech variable speed motor, Tagelus TA-60 filter with zeolite media, Liquidator, AquaComfort heat pump, Blue-White flowmeter, Smartpool Wall Climber
    TF-100, LaMotte metal sequestrant test kits
    Sundance Capri hot tub

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    9,085

    Re: Bonding Mystery - Pool Light

    I'd say what is happening is that the bonding is doing its job, and what you need to look for is the source of the current. Hard to guess what that could be. Reversed hot and neutral someplace or a loose neutral, defective underground power or phone wiring or maybe a problem with your utility's power delivery system.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  3. Back To Top    #3

    ChuckDavis's Avatar
    Join Date
    Aug 2010
    Location
    Durham, NC
    Posts
    73

    Re: Bonding Mystery - Pool Light

    Thanks for your quick response.

    Other than the niche and pool light, there is no metal in contact with the water. (No stairs, rails, etc.)

    I had the entire pool system rewired by an electrical contractor. Beauzeax, my name for the previous homeowner who installed the pool.............and who owned a pool construction company (!), had totally screwed it up. An AFCI on the light, no GCFI's anywhere else, and the bond wires disconnected since they caused the AFCI to trip. (I wonder if there's a clue there.) The new GCFI has not tripped.

    Beauzeax had reversed hot and neutral at the receptacles in a non-permitted buildout of the garage into an apartment, but I corrected that.

    No Telco wiring since I'm using VoIP from my cable provider.

    The pool and pool light are around 15 years old. Is there any chance the power cord to the light is failing and leaking some current?

    Can you think of any test points to determine if/where there is a voltage differential? Is there any way to test for leakage from the pool light power cord with the pool now being refilled?

    (Here's another laugh. Beauzeax ran 75 feet of undersized gas line from the meter to the (now removed) pool heater............USING PVC! The undersized pipe caused the burners in the heater to run cool and moist, which rusted out the burners and baffles.)
    15,000 gallon IGP, epoxy surface, waterfall, borates (!), not closed in winter
    SuperPump with 2.4 THP EcoTech variable speed motor, Tagelus TA-60 filter with zeolite media, Liquidator, AquaComfort heat pump, Blue-White flowmeter, Smartpool Wall Climber
    TF-100, LaMotte metal sequestrant test kits
    Sundance Capri hot tub

  4. Back To Top    #4
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    9,085

    Re: Bonding Mystery - Pool Light

    I expect if you pull the bond wire off the pump you'll see a voltage. If you can find a place were you can measure a voltage, you can try switching things off to check for changes.

    Even problems with a neighbor's wiring could show up in your pool.

    Google "stray voltage" to get some ideas.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  5. Back To Top    #5

    ChuckDavis's Avatar
    Join Date
    Aug 2010
    Location
    Durham, NC
    Posts
    73

    Re: Bonding Mystery - Pool Light

    There was no measurable voltage at the pump, although my VOM only goes down to a 2 VDC range. There is a slight amount of DC current (.002-.004 milliamps) between the bond wires from the light and the pool deck to the pump bonding lug. (The heat pump is currently disconnected from the pool plumbing.)

    I'm thinking of installing sacrificial anodes on the pool light and in the main plumbing, probably near the heater. Potential brand: http://pooltool.com/anodes.html.

    Does anybody have any recommendations for, against or alternatives?

    Thanks.
    15,000 gallon IGP, epoxy surface, waterfall, borates (!), not closed in winter
    SuperPump with 2.4 THP EcoTech variable speed motor, Tagelus TA-60 filter with zeolite media, Liquidator, AquaComfort heat pump, Blue-White flowmeter, Smartpool Wall Climber
    TF-100, LaMotte metal sequestrant test kits
    Sundance Capri hot tub

  6. Back To Top    #6
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Bonding Mystery - Pool Light

    Quote Originally Posted by ChuckDavis
    There was no measurable voltage at the pump, although my VOM only goes down to a 2 VDC range. There is a slight amount of DC current (.002-.004 milliamps) between the bond wires from the light and the pool deck to the pump bonding lug. (The heat pump is currently disconnected from the pool plumbing.)

    I'm thinking of installing sacrificial anodes on the pool light and in the main plumbing, probably near the heater. Potential brand: http://pooltool.com/anodes.html.

    Does anybody have any recommendations for, against or alternatives?

    Thanks.
    DVOMs are wildly inaccurate when measuring AC set on DC and vice versa. Borrow a meter with an AC setting.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  7. Back To Top    #7

    ChuckDavis's Avatar
    Join Date
    Aug 2010
    Location
    Durham, NC
    Posts
    73

    Re: Bonding Mystery - Pool Light

    My (el cheapo Radio Shack) VOM has AC volts, DC volts and DC milliamps.
    15,000 gallon IGP, epoxy surface, waterfall, borates (!), not closed in winter
    SuperPump with 2.4 THP EcoTech variable speed motor, Tagelus TA-60 filter with zeolite media, Liquidator, AquaComfort heat pump, Blue-White flowmeter, Smartpool Wall Climber
    TF-100, LaMotte metal sequestrant test kits
    Sundance Capri hot tub

  8. Back To Top    #8
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Bonding Mystery - Pool Light

    Quote Originally Posted by ChuckDavis
    My (el cheapo Radio Shack) VOM has AC volts, DC volts and DC milliamps.
    Your pump is AC, correct? You said you measured it on the 2VDC scale. That's why I mentioned it.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  9. Back To Top    #9
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Bonding Mystery - Pool Light

    .002-.004 milliamps is exceedingly low and nothing to worry about, assuming you measured it correctly (see Richard320's comments).
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  10. Back To Top    #10

    ChuckDavis's Avatar
    Join Date
    Aug 2010
    Location
    Durham, NC
    Posts
    73

    Re: Bonding Mystery - Pool Light

    Per the suggestion above from JohnT, I disconnected the bond wires and then measured between each bond wire and the bonding lug on the motor.
    15,000 gallon IGP, epoxy surface, waterfall, borates (!), not closed in winter
    SuperPump with 2.4 THP EcoTech variable speed motor, Tagelus TA-60 filter with zeolite media, Liquidator, AquaComfort heat pump, Blue-White flowmeter, Smartpool Wall Climber
    TF-100, LaMotte metal sequestrant test kits
    Sundance Capri hot tub

  11. Back To Top    #11

    Re: Bonding Mystery - Pool Light

    A friend of mine had this exact problem. After numerous people changing the light and running electrical tests, etc. they found the problem. They did a 9 point test on his water and found he had copper in his pool water which was causing the problem. They poured a solution for metals into his pool and it was corrected. I hope this helps.
    Pool Size=23,000 gallons
    DE Filter = DNS 48 sqft
    In ground pool

  12. Back To Top    #12

    ChuckDavis's Avatar
    Join Date
    Aug 2010
    Location
    Durham, NC
    Posts
    73

    Re: Bonding Mystery - Pool Light

    Thanks, Sunngurrl. I just finished my annual stain treatment that lifts and sequesters iron and copper stains. In my case it may be a chicken or egg issue. Other than the heat pump and pool light, I have no source of metals. It may be galvanic corrosion that is putting the metals into the water. I have added sacrificial zinc anodes just upstream of the heat pump and attached to the pool light. We'll see what happens.
    15,000 gallon IGP, epoxy surface, waterfall, borates (!), not closed in winter
    SuperPump with 2.4 THP EcoTech variable speed motor, Tagelus TA-60 filter with zeolite media, Liquidator, AquaComfort heat pump, Blue-White flowmeter, Smartpool Wall Climber
    TF-100, LaMotte metal sequestrant test kits
    Sundance Capri hot tub

  13. Back To Top    #13

    Re: Bonding Mystery - Pool Light

    He found out the source of copper was coming from the water out of his hose to fill pool. In older communities they still have copper piping that the city/county water runs through. Good luck!
    Pool Size=23,000 gallons
    DE Filter = DNS 48 sqft
    In ground pool

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •