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  1. #1
    Join Date
    Sep 2019
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    1
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    Confused Water accumulating in junction boxes/switches in commercial cooler ceiling

    Hello there,
    I've run into this issue twice this week in two separate coolers in my building. (I took over as a facility manager recently and there had not been one for a long time, so I've been playing A LOT of catch up).
    The issue is water accumulating in electrical junction boxes and shut off switches that have been installed on the ceilings of our commercial coolers. One cooler is 14'6 x 22, with a 25ft ceiling. The other is 11'6 x 34, 7ft ceiling. In both cases the emergency sprinkler lines had degraded caulking on the top of each cooler, not too difficult to re-do. I had assumed the sweating of the pipes above the cooler had traveled through the ceiling panels (aluminum for both) and found the closest opening to escape, in both cases being wiring junction boxes for cooler lights and fan box on/offs. Fan box drains both work fine, and are not located near the junction boxes. Even after re-sealing the entry points on the roof of the coolers of the sprinkler pipes, I'm still getting some water in my junction boxes.
    Any ideas? Junction boxes are insulated and sealed to keep moisture from getting in from the OUTSIDE of the boxes, so I feel water must be getting in from the ceiling panels somehow. (Both units are dry on the outside ceiling)

  2. #2
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    27,195
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    Seal the conduit before it penetrates the box, warm moist air is traveling down the conduit and condensing in the inside boxes.

    We also remove the seals inside to allow the water to get out!

  3. #3
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    3,353
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    pecmsg has nailed it. This is a very common problem. The electrical boxes on the outside of the coolers/freezers should be weather-proof boxes, and the ones on the inside should be regular ones. I have never seen them installed this way though. For some reason everyone likes to put the vapor barrier on the wrong side of the envelope, and this is the result.

    Do as pecmsg does. If the junction/switch box covers inside of the coolers/freezers have gaskets, remove the gaskets and/or drill a small hole or remove a knockout or something, so that any humidity that's getting sucked in from the outside can make it's way to the evaporator coil like it's supposed to. Then try to seal up the source of the humidity, which are usually junction boxe on the warm side of the wall/ceiling. Open up those junction boxes and either jam some thumb-gum into the hole that the wires are going thru, or pump some silicone into there.
    If at First You Don't Succeed, Skydiving Is Not for You.

  4. #4
    Join Date
    Feb 2016
    Location
    Louisburg Kansas
    Posts
    4,102
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    pecmsg nailed it.
    No man can be both ignorant and free.
    Thomas Jefferson

  5. #5
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    32,177
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    Yep.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist
    Member, IAEI

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  6. #6
    Join Date
    May 2019
    Posts
    43
    Post Likes
    If there is a common wall between WIC and WIF even that temp differential is enough to cause water vapor transfer via conduits. Actually any pipe going from inside to outside of a building needs sealed. I have found water on the top of electric panel mains caused by open pipes to the exterior.

  7. #7
    Join Date
    Jun 2006
    Posts
    679
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    I have used both silicone and expanding foam to seal the inside of the conduit with success.

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