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Joined: Jul 2004
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G
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Why is the water level an issue if there are no splices below the dock? You could run that conduit under water if you wanted to. I said you could use "T" conduit bodies but it might be better to use 2 hole boxes and have the conduits daisy chain with no openings under the dock at all, (one in, one out) although they will accumulate water no matter where they are if they are below the boxes. I have never pulled a wire out of an underground conduit that wasn't wet it it had been there a while.
That is the standard install around here. The conduits run under the dock and come up to each box. These docks may be submerged in salt water occasionally. They were on Monday anyway. (T/S Colin)


Greg Fretwell
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Joined: Apr 2002
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Just my two cents....
Did you or anyone check with a building inspector regarding the walkway, with only the top & lower rails?? I don't think that would fly here.

The additional 2x12 would be a lot more inexpensive a solution, and 'maybe' be required.

The PVC coated RGS is a great solution, but keep in mind it is $$$, and requires a dedicated bender.

Unistrut makes fiberglass and stainless strut FYI.

Schedule 80 PVC would be my choice, and I would seriously 'nudge' the 2x12s perhaps on both sides for appearance. (And it may make the insurance co. happy)


John
Joined: Oct 2002
Posts: 830
S
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Greg, I'm talking about the walkway out to the dock. I don't think the inspectors here are going to go for the pvc in the water. As far as running it under the walkway, I'd have to swim under the walkway and use a "snorkel" or something, plus run out all the snakes if any. Already had to run out one snake on the dock itself. After the inspector seeing what shape it was in before, I'm sure it's going to have to be out of the water. And yes, I did have an inspector out there before I did anything. He's the one that required me to rewire it. I tried to meet with one of the plan review personnel this morning, but he referred me to the same inspector over the phone, and he pretty well didn't give me any other information than I knew. I guess this is just a "design issue" and they didn't want to get into it. I guess he figures I can read the Code just like them, which I can, but there's sometimes "gray areas" in there as we all know. Plus where this job is, is back in the "boonies" so to speak. Takes a while to get there. No supply houses real handy, so I have to try to make each trip effective as possible.
I've already pretty well got the lights under the dock roof wired, just a few more things. I'm just getting ready to run the feed and switch legs. Still got some bonding to do on the ladders, ramp, etc..
John I will check on the fiberglass or stainless Unistrut.
Thanks for all your comments. Just wanting to do it right and safe as possible and not make it look too tacky at the same time. This establishment if for "The Lions Club" which
does things for the blind and visually impaired. They have certain times they come in big groups and have staff members help them enjoy boat rides and swimming. Actually they are there now, so I'm limited when I can work. It has to be late in the afternoons or on Saturdays. After all the news about the fatalities of electric shock around boat docks for swimmers, I'm trying to be extra safe as I can. I know most of those fatalities are associated with boat lifts etc., but they don't want me to cut corners.
Thanks again

Last edited by sparkync; 06/08/16 05:35 PM.
Joined: Jan 2005
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Cat Servant
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I believe strut is also available in aluminum .... check McMaster-Carr for a full selection.

OK, fine, use PVC .... but support it as continuously as you can. Like, lengthwise along strut as pictured with the clamps I linked to. You could even do most of that using wood and 2-hole straps.

The key is complete support under the PVC for the entire length. Otherwise, PVC will sag, look poor, and it becomes brittle with time. There's also the risk of the pipe being used as a tie-off point foothold, etc. These are additional reasons for 'going big.'

As for the fear of electrical shocks in the water .... just a silly idea here ... How about running a #4 copper wire down each pier into the water, and bonding them to your circuit ground? That would surely reduce the chance of any "voltage gradients."

Contrary to common practice in our trade, I'd also clean & prime the PVC before applying glue.

BTW, stainless conduit and fittings exist.

Last edited by renosteinke; 06/08/16 11:39 PM.
Joined: Jul 2004
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G
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If you do not want to get in the water, no problem but I do not see an issue code wise about running it under the walk way. It looks to be above the water anyway in your picture but there is no code reason why it can't be underwater if it had to be. It is still a wet location.
I do agree with Reno, PVC will never look great if you have to look at it but those PVC 2 hole straps do not hold up. I would use something else.

Call the AHJ and ask what he wants to see. This can't be the only dock they have wired around there.


Greg Fretwell
Joined: May 2005
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G
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I agree that the PVC-coated rigid costs a bit more, but here's an 'outside the box' idea since you said that it's for such a worthy cause.

Since PVC-coated conduit is used in water, wastewater and chemical installations, ask around and see if there are any Contractors who have leftovers from a previous job that they're stuck with.
They might be persuaded to donate a few lengths...perhaps for a tax writeoff.
The local water/wastewater plants may even have something usable in their scrap pile from a renovation that you could have for the asking.

Based on the pictures you could do the whole job with several straight lengths and may only have to buy a few fittings and boxes.

smile


Ghost307
Joined: Oct 2002
Posts: 830
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Greg, how do you get past the supports every 3 ft. when running under water or even under the walkway I pictured, where I can't get too?
And Reno, your comment about it being a silly idea of electric shocks in the water. I've been reading of a lot of fatalities of people getting eletocuted while swimming. Maybe I'm misunderstanding what you meant. Right now I can't remember the name of what it is technically called.

Next time I get a chance I'll ask our inspectors here about running the pvc under water.
Thanks again for the input.

Joined: Jul 2004
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G
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You should be able to run it inside the horizontal stringers the deck boards screw into but I was looking at your picture again.
You could run the pipe along those tails that stick out at each piling. Maybe have them nail a 2x along the ends for support. Then you won';t have to get in the water at all.

[Linked Image from gfretwell.com]


Greg Fretwell
Joined: May 2005
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G
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Keep in mind that if it can be reached from the water a swimmer will use it as a handhold sooner or later.


Ghost307
Joined: Oct 2002
Posts: 830
S
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The side that is designated for swimmers is roped off and these swimmers are monitored, because most of them are visually impaired, but I know what you mean. If it's possible it'll be done. If I add the 2x12 it should protect the conduit from being in any sort of strain from hand holds in the future. They will be grabbing hold of the 2x12 .
If it works out, I'll probably just running the 2x12 on the left side of the walkway, which is on the opposite side that is designated for swimming. I'm suppose to go out this afternoon to look it over again, and tomorrow to do work on the dock. I'm going to try to get on the water and see if there is an option before I make my final decision. And no, I'm not for getting in the water. At my age it wouldn't be fun, plus I'm not the Olympic swimmer by no means frown
But thanks for the inputs. I will certainly keep all of these in mind.

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