My statement, in red, is true. 300.4(H) is regarding all raceways. Are you saying PVC isn't a raceway???
I agree PVC is a raceway and is covered in 300.4(H) as being required to have an expansion joint across a point of expansion in a structure, guess I wasn't trying to disagree with you but trying to point out that because of the way he mention that the run was 80' I took it as the inspector was rejecting the car flex which we both know that it is also an accepted method because 352.44 only require the expansion joint for straight runs between fixed mounted items
Maybe you are misinterpreting my point, and/or perhaps I am not making my point clearly. I tend to be succinct, while from my perspective you tend to be a bit wordy.
Ya been accused of writing a book or two when I respond, I have a bad habit of trying too hard to make sure someone understands what I'm trying to say or not sure if the poster is understanding , so I tend to ramble too much:ashamed1: but when you posted the reference to 300.4(H) I couldn't figure out the reason as with tidal movement or up and down movement a linear expansion joint would not be a good choice from land to a dock, guess my response could have been worded using much less words LOL
352.44 requires expansion fittings for straight runs between securely mounted items. If as stated in the OP, a 1' section of Carflex is inserted in the run every 25', then the straight runs (of PVC) do not exceed 25' and they are not between securely mounted items (assuming Carflex is not securely fastened). That makes 352.44 moot under the conditions of installation.
Correct unless the inspector is thinking the car flex (LNMFC) is subject to damage? even a 90? turn up into a box can eliminate the requirement of an expansion joint as the pipe can expand some if the pipe hasn't been strapped right at the 90? point we see this type of expansion system used in steam lines all the time, but without the reason or the thinking of the inspector who knows?
As for using a flexible wiring method at the shore to water-structure transition, note 300.4(H) says "or other approved means"... which means it is at the discretion of the AHJ whether the other means is acceptable. Even with first hand observation of the installation, my opinion don't matter... but I would likely approve it if I were in that position.
Again just a linear expansion joint at the land to dock point will not provide for up and down tidal movement or waves which would eventually break the pipe, not a good design choice, I wired many docks in Florida which has probably the least amount of tidal change with going farther north having more as you get north, and we always provided a flexible method at the point of transition from land to dock, unless the dock was of a stationary non-floating type, but then if it were a fixed type then there would be no reason for any expansion joint as being that both are mounted to land and the fact that the land should not move in reference to each other then the only consideration would be thermal expansion, we had coated RMC that would come right out of the concrete wall that a fixed dock was bolted to and run right onto the dock and never had a problem, well until Hurricane Andrew hit my dad's place, which is not a normal situation and a expansion joint would have not helped because the dock was gone
I guess this was the part that I didn't understand why you sited 300.4(H)
Another thought is, one expansion fitting can serve a dual purpose in compliance with both 300.4(H) and 352.44.
Very true, anytime you can use one item for dual purpose it always saves money
And that falls under 300.4(H) in conjunction with 300.5(J) ... not 352.44.
correct more so to the requirement of 300.5(J) if 300.4(H) covered it then why the need for 300.5(J)? to me the requirement in 300.4(H) is more for where a raceway crosses two point of a building or structure that the structure can move or expand but the raceway doesn't, where the raceway can expand but not the structure then these requirements will be in their respective article for the raceway such as 352.44 which I'm not sure but is about the only type of raceway I think the NEC requires an expansion joint for thermal reasons? I couldn't even find any requirements for other non-metallic raceways which is kind of strange, you would think that Aluminum RMC would have some kind of requirement for thermal expansion?, I know at work you can hear the aluminum conduit making a kind of popping sound as it moves under the u-bolts we use to secure it, at night when it gets cooler.
For some reason I have always thought even RMC had some kind of expansion requirment for really long runs as I remember installing expansion joints on very long runs?? but at quick glance I didn't find any.