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Joined: Jul 2004
Posts: 9,923
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G
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The river by my house is lined with docks and lifts. There are also canals for additional dock space so we have lots of work going on. I doubt 20% of it is permitted and inspected.


Greg Fretwell
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Joined: Oct 2002
Posts: 830
S
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Got the 2x10s up. I'll try to post a picture when I get time. Just,wondering how many expansion couplings I would need on a 100ft. Run of 3/4" pvc conduit?

Joined: Jul 2004
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G
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If you design for 100f degree swing and 100 feet out, it is 4.06" according to table 352.44
Carlon has a pretty good guide
https://www.platt.com/CutSheets/Multiple/ConduitExpansionFittings-CutSheet.pdf


Greg Fretwell
Joined: Jul 2004
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G
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One thing to remember is if you elbow up and down to each light along the way, you are breaking up that expansion and if you don't strap the vertical too close to the elbow, you get quite a bit of "wiggle room". I don't really see than many expansion fittings if they can do a flexible enough design.


Greg Fretwell
Joined: Oct 2002
Posts: 830
S
Member
I will have 1 (3/4) run the length of the walkway feeding the boat dock. I will run the lights on the walkway in 1/2". I figure the 3/4" is the one mainly that,will need the expansion fitting.

Joined: May 2005
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G
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Both runs them will expand and contract with the temperature changes...and to the same degree.
I'd put 2 expansion joints in each run; it's cheaper than maxing out the one fitting on a really hot day and having to rip everything out and start over.


Ghost307
Joined: Jul 2004
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As long as the run has regular (interval) elbows up and down for the lights, that will usually handle the expansion. Just be careful not to strap too close to the elbow on the verticals so they have some wiggle room. You can strap the horizontal a few inches from the elbow to secure it as long as the pipe can move. On the long run, I would use several expansion couplers so they spread out the work. You don't want the pipe to bind, halfway down and pull apart or rip out the straps. Those plastic straps are junk anyway. I would go for stainless 2 holers if you can get them. I know the dock guys use them here so they are available. It may be a plumbing store thing.


Greg Fretwell
Joined: Oct 2002
Posts: 830
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Can't seem to be able to find the exact type flex needed between the pier and the ramp needed for flexibility. I know it has to be watertight, but can it be carflex. Looks like if you use flexible metal that the metal ground would eventually break into with all the up down motion of the water. Also, article 555(I think that's right) says it is not for private or non commercial use. Please refresh6 me on the article that does pertain to it. It's been a rough job bouncing on the the waves and my brain is sorta bouncing too. Thanks

Joined: Jul 2004
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G
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555.13(A)(2) says you can use SO cord (assuming the right grips on each end) If you needed additional protection I guess you could sleeve that in Carflex since it is a chapter 3 wiring method as stated in 555.13(A)(1), pursuant to protection in 555.13(B)(a)(5). If there are sections above the deck you need RNC per 555.13(B)(5)


Greg Fretwell
Joined: May 2005
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G
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Just make sure that you get the UV and water resistant cord or you'll be replacing it next season.


Ghost307
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