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Thread: Strapping nipples

  1. #11
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    My thought on this has always been if you had something like a 3 inch RMC 24" long between two large cabinets and you are forced to put a strap on it by code, is the strap supporting the conduit or is the conduit supporting the strap? You can mix and match raceway sizes and types and even tweak length a little and still say the same thing for most of them.
    I live for today, I'm just a day behind.

  2. #12
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    This is one of those things where in my opinion the code should be revised to allow leeway to installers and AHJs. (I mean, I haven't had issues with AHJ's requiring me to strap short pieces of conduit that was secure in fittings. But if people are...)

    Take for example a piece of EMT, 18" long, with no bends, installed between two set-screw fittings on two enclosures that are securely fastened to the same wall. That ain't goin' nowhere. It doesn't need to be strapped.

    Now take the same piece of EMT, put a 90deg bend in the middle of it, and move one of the enclosures up so that the EMT enters from the bottom instead of the side. That elbow will wobble around a bit and arguably needs a strap.
    Now try to write a code section that precisely covers all the other examples. This is one of those situations where I'd be okay with undefined language that the AHJ gets to interpret (i.e. similar to 'subject to physical damage).

  3. #13
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    Quote Originally Posted by jaggedben View Post
    Take for example a piece of EMT, 18" long, with no bends, installed between two set-screw fittings on two enclosures that are securely fastened to the same wall. That ain't goin' nowhere. It doesn't need to be strapped.
    I could see the EMT size being taken into consideration here. A 1/2" EMT nipple 18" long might need midway support where a 2" EMT nipple 18" long might not. Maybe it should be a given multiple of diameter.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  4. #14
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    Quote Originally Posted by LarryFine View Post
    I could see the EMT size being taken into consideration here. A 1/2" EMT nipple 18" long might need midway support where a 2" EMT nipple 18" long might not. Maybe it should be a given multiple of diameter.
    That's why I think it should be vague, something like 'a length less than 18" shall be permitted to be mechanically secured by associated fittings'. Let reasonable people decide if it's 'mechanically secured'.

  5. #15
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    Quote Originally Posted by jaggedben View Post
    That's why I think it should be vague, something like 'a length less than 18" shall be permitted to be mechanically secured by associated fittings'. Let reasonable people decide if it's 'mechanically secured'.
    I don't have much issue with that but think it should be 3 feet especially if we don't need a first support until 3 feet on other runs.
    I live for today, I'm just a day behind.

  6. #16
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    Quote Originally Posted by kwired View Post
    I don't have much issue with that but think it should be 3 feet especially if we don't need a first support until 3 feet on other runs.

    I agree, two solidly mounted boxes on a block wall with a 36" piece of EMT between them isn't going anywhere. They should have at least left the 18" exception in place.
    Rob

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    All responses based on the 2014 NEC unless otherwise noted

  7. #17
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    Quote Originally Posted by infinity View Post
    I agree, two solidly mounted boxes on a block wall with a 36" piece of EMT between them isn't going anywhere. They should have at least left the 18" exception in place.
    If you have 3 feet then a piece of unistrut to attach it to, it is kind of similar situation. Then they even let you go up to 5 feet in certain situations where you don't have structural means within 3 feet.
    I live for today, I'm just a day behind.

  8. #18
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    Quote Originally Posted by infinity View Post
    All EMT nipples require support even one that's 2" long. There was one code cycle where you could have up to 18" nipples unsupported but that didn't last long.
    Which code cycle was that?

  9. #19
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    Quote Originally Posted by jaggedben View Post
    Which code cycle was that?
    From the 2008 NEC:

    358.30(C) Unsupported Raceways. Where oversized, concentric
    or eccentric knockouts are not encountered, Type EMT
    shall be permitted to be unsupported where the raceway is
    not more than 450 mm (18 in.) and remains in unbroken
    lengths (without coupling). Such raceways shall terminate
    in an outlet box, device box, cabinet, or other termination at
    each end of the raceway.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

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