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Thread: Roof penetration & support

  1. #41
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    Quote Originally Posted by Smart $ View Post
    So are we unconfused yet?
    No,

    Does the threaded pipe have to thread into the hubs directly without any fittings or not?

    Most all of the NEC drawings show it that way.

    JAP>

  2. #42
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    Quote Originally Posted by wwhitney View Post
    I thought PVC male adapters use tapered threads, like their plumbing analogs (although I believe I've seen assertions both ways on this forum). In which case the same logic would allow PVC to support a box.

    BTW, I'm not convinced by your argument that the threads have to be on a stick of conduit and not a fitting, but I agree it is one reasonable interpretation of the text.

    Cheers, Wayne
    To me a PVC Male Adapter is a fitting, not the conduit itself.

    It's not natural to thread PVC Coduit, although I guess you could if one wanted to be silly about it.


    JAP>

  3. #43
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    Quote Originally Posted by wwhitney View Post
    ...
    BTW, I'm not convinced by your argument that the threads have to be on a stick of conduit and not a fitting, but I agree it is one reasonable interpretation of the text.
    Even if fittings are permitted, the section specifically uses the word conduit, not raceway, so EMT is definitely out.

    The reason I mostly say fittings cannot be used is that threaded entries and hubs are generally female NPT tapered threads. AFAIK, no connector (i.e. a fitting) has been investigated for grounding continuity when used with other than a locknut to secure it.
    Last edited by Smart $; 09-20-17 at 02:57 PM.
    I will have achieved my life's goal if I die with a smile on my face.

  4. #44
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    Quote Originally Posted by Smart $ View Post
    Even if fittings are permitted, the section specifically uses the word conduit, not raceway, so EMT is definitely out.
    EMT is definitely out because of (2011) 358.12(5), not because of 314.23(E).

    If (2011) 314.23(E) consistently used the word conduit rather than the word raceway your argument would demand consideration. But it uses the word raceway twice and then the word conduit twice. IMO the usage is not clear enough or consistent enough to rise to the level of an intentional distinction to exclude some raceways.

    Quote Originally Posted by Smart $ View Post
    The reason I mostly say fittings cannot be used is that threaded entries and hubs are generally female NPT tapered threads. AFAIK, no connector (i.e. a fitting) has been investigated for grounding continuity when used with other than a locknut to secure it.
    Clearly an important concern, but one that is moot for PVC raceway. Also, if the metal conduit carried a wire type EGC inside, that also would also obviate the issue, right?

    Cheers, Wayne

  5. #45
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    Quote Originally Posted by wwhitney View Post
    EMT is definitely out because of (2011) 358.12(5), not because of 314.23(E).

    If (2011) 314.23(E) consistently used the word conduit rather than the word raceway your argument would demand consideration. But it uses the word raceway twice and then the word conduit twice. IMO the usage is not clear enough or consistent enough to rise to the level of an intentional distinction to exclude some raceways.


    Clearly an important concern, but one that is moot for PVC raceway. Also, if the metal conduit carried a wire type EGC inside, that also would also obviate the issue, right?

    Cheers, Wayne
    Points taken. My rebuttal is 314.23(E) specifically states "It shall be supported by two or more conduits threaded wrenchtight into the enclosure or hubs. Each conduit shall be secured within 900 mm (3 ft) of the enclosure, or within 450 mm (18 in.) of the enclosure if all conduit entries are on the same side." And (F) also specifically states "It shall be supported by two or more conduits threaded wrenchtight into the enclosure or hubs. Each conduit shall be secured within 450 mm (18 in.) of the enclosure." These statements render the use of the word raceway quite moot.

    FWIW, hubs are always tapered thread and do not leave any room for a locknut. Some threaded enclosures have so few threads, it's hard to tell whether they are tapered or straight (such as some bell boxes). There is enough thread inside to install a locknut... but how many actually do?

    When using metal conduit, continuity of ground is required. I know many believe that one end is all you need but take jap's posted detail as an example. You can only bond one end anyway. Yes, the wording is vague enough to not exclude conduit such as PVC, which I believe is a major blunder. I would submit a public input to this effect next cycle but I'm getting less ambitious by the day in my current condition. Who knows how I'll feel or if I'll even remember next input cycle. Maybe someone caught it for 2020 but we can't check until comment stage (right?).

    I will have achieved my life's goal if I die with a smile on my face.

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