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Thread: Inverters in a lay-flat setup on rooftops - distance from roof edge

  1. #1
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    Inverters in a lay-flat setup on rooftops - distance from roof edge

    To comply with 2014 & pre-2019 of 2017 rapid shutdown, it is common to lay inverters nearly flat, and mount adjacent to the array. For shading reasons, it is preferable for these to be at the north edge of the array, which inevitably puts pressure on the design decision to put these close to the edge of the roof.

    The question is, assuming structural integrity is not a concern, how close can the inverter be to the edge of the roof, regarding safe maintenance practices?How much space minimum is required for the human body plus a safety margin, does one need for safely working on the roof, given that there is no guardrail or sufficient parapet along the edge?

    NEC110.26, doesn't have a "condition 4", for an unprotected roof/deck/platform edge. The design in question has only 6 ft from the edge surface of the inverter to the roof edge, and I have an instinctive feeling that it wouldn't be safe.

  2. #2
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    Oct 2009
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    Quote Originally Posted by Carultch View Post
    To comply with 2014 & pre-2019 of 2017 rapid shutdown, it is common to lay inverters nearly flat, and mount adjacent to the array. For shading reasons, it is preferable for these to be at the north edge of the array, which inevitably puts pressure on the design decision to put these close to the edge of the roof.

    The question is, assuming structural integrity is not a concern, how close can the inverter be to the edge of the roof, regarding safe maintenance practices?How much space minimum is required for the human body plus a safety margin, does one need for safely working on the roof, given that there is no guardrail or sufficient parapet along the edge?

    NEC110.26, doesn't have a "condition 4", for an unprotected roof/deck/platform edge. The design in question has only 6 ft from the edge surface of the inverter to the roof edge, and I have an instinctive feeling that it wouldn't be safe.
    Most jurisdictions I deal with require that all serviceable equipment (which includes inverters and load centers but not PV modules and conduit) be located >10' from a roof edge.

  3. #3
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    Quote Originally Posted by ggunn View Post
    Most jurisdictions I deal with require that all serviceable equipment (which includes inverters and load centers but not PV modules and conduit) be located >10' from a roof edge.
    Should I expect every jurisdiction to possibly have a different answer? Any state or national standards which would cause jurisdictions to have a more consistent answer?

  4. #4
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    Quote Originally Posted by Carultch View Post
    Should I expect every jurisdiction to possibly have a different answer? Any state or national standards which would cause jurisdictions to have a more consistent answer?
    I'm pretty sure that it's a building code issue.

  5. #5
    Join Date
    Dec 2012
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    Quote Originally Posted by ggunn View Post
    I'm pretty sure that it's a building code issue.
    Jurisdictions may also have a local or state fire code which is supplemental to the building code rather than part of it.

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