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Thread: Plenum connection?

  1. #1
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    Plenum connection?

    I have been requested to supply a large quantity of lighting fixtures with fmc or other whips and disconnects to be installed in a plenum. The lighting fixtures will not be in the plenum but the requested disconnect will be. It is a large commercial project and will require code compliance. I know no code compliant method to provide a plenum rated disconnect or male / female whip for power (120v/277v). Does a solution exist?

  2. #2
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    Do you know of a Code section which prohibits a disconnect in a plenum?

    Exactly what type of plenum are we talking? One specifically designed for handling environmental air, or not, such as above a typical commercial suspended ceiling that is used for air return.
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  3. #3
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    Quote Originally Posted by Smart $ View Post
    Do you know of a Code section which prohibits a disconnect in a plenum?

    Exactly what type of plenum are we talking? One specifically designed for handling environmental air, or not, such as above a typical commercial suspended ceiling that is used for air return.
    The plenum is for return air, typical for many commercial buildings. Section 410.62(c)2a. requires that the cord in a cord connected fixture must be visible for it's entire length. This application would have much / most of the "cord" located in the plenum.

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    Quote Originally Posted by mlahner View Post
    The plenum is for return air, typical for many commercial buildings. Section 410.62(c)2a. requires that the cord in a cord connected fixture must be visible for it's entire length. This application would have much / most of the "cord" located in the plenum.
    FMC / MC whips are not cords. Where is the disconnect requirement? Fluorescent ballasts, yes. LED, I do not believe so. Are these just customer requests that you are referring to?

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    Quote Originally Posted by mlahner View Post
    The plenum is for return air, typical for many commercial buildings. Section 410.62(c)2a. requires that the cord in a cord connected fixture must be visible for it's entire length. This application would have much / most of the "cord" located in the plenum.
    I am still not sure you are clear on the distinction between two types of air handling space.
    If a closed "duct" or space is created just for the purpose or air handling it is a plenum. One example would be if half of an attic space above an office or work floor was partitioned off to cover air return ducts along one side of the space. Constructed for the purpose ---> plenum. Access would be by door(s) or hatches for that purpose.
    If the space above a dropped ceiling has return air vents is some tile locations that do not connect to ductwork and large return air vents somewhere that suck from that space, it is an "environmental air handling space", not a plenum.
    That said, many NEC restrictions apply to both air spaces and plenums.

  6. #6
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    Quote Originally Posted by GoldDigger View Post
    ... it is an "environmental air handling space", not a plenum.
    ....
    The NEC still calls it a plenum. 300.22 "(C) Other Spaces Used for Environmental Air (Plenums)."
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    Yes, this will not be a duct constructed for the purpose so it will be an air handling space. The disconnect requirement is from the architect to allow access to roller shades mounted above.

    So what type of male / female plug or disconnect would be acceptable on an FMC cable used in an air handling space?

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    Quote Originally Posted by mlahner View Post
    Yes, this will not be a duct constructed for the purpose so it will be an air handling space. The disconnect requirement is from the architect to allow access to roller shades mounted above.

    So what type of male / female plug or disconnect would be acceptable on an FMC cable used in an air handling space?
    I do not know of any that are listed or identified for FMC termination. I believe you are looking at installing switches in the j-box (device box) to which you connect the whip. RFI the architect. Apparently, he doesn't know Code as well as he thinks.
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  9. #9
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    Quote Originally Posted by mlahner View Post
    I have been requested to supply a large quantity of lighting fixtures with fmc or other whips and disconnects to be installed in a plenum. The lighting fixtures will not be in the plenum but the requested disconnect will be. It is a large commercial project and will require code compliance. I know no code compliant method to provide a plenum rated disconnect or male / female whip for power (120v/277v). Does a solution exist?
    Not sure if they're plenum rated, but the Reloc line of connectors come with FMC whips:

    http://www.acuitybrands.com/products...ing#t=Products

    Their website is a trainwreck, and I can't tell exactly what you'd need to build a connectorized solution. Probably best to call them on Monday.


    SceneryDriver

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    Quote Originally Posted by SceneryDriver View Post
    Not sure if they're plenum rated, but the Reloc line of connectors come with FMC whips...
    Forgot all about RELOC. Probably because OP said FMC was spec'd and I consider RELOC whips as MC. I don't know if their whips are plenum rated either, but I have installed gobs of them in plenum locations.

    Being more than just a wiring method, compliance with 300.22(C)(3) is required. While the connectors essentially form a metallic enclosure around the connection, what about when disconnected?
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