Installing underground conduit on tidal beach

[buzzbar]

Hi all,

I'm bidding on a job that is on a salt water shoreline. I need to run a 60A subfeeder from a house on shore, out to a dock. The easiest path is to dig a trench along the beach, at the highest point. Installing the trench on shore is POSSIBLE, but very complicated because there are several very old trees, with large roots everywhere.

My question is this: Is it allowed by the NEC to install an underground conduit in a trench on the tidal beach? This conduit would be underneath water during the winter, during a very high tide.

Secondly, even if the NEC allows it, does anyone know any other reason that this would not be allowed?

My thought is that this would be a no-no, because of the unpredictable nature of the salt water beach.

I appreciate any information or opinions on this.

Thanks!

Andrew

 

[Gregg Harris]

Hi all,

I'm bidding on a job that is on a salt water shoreline. I need to run a 60A subfeeder from a house on shore, out to a dock. The easiest path is to dig a trench along the beach, at the highest point. Installing the trench on shore is POSSIBLE, but very complicated because there are several very old trees, with large roots everywhere.

My question is this: Is it allowed by the NEC to install an underground conduit in a trench on the tidal beach? This conduit would be underneath water during the winter, during a very high tide.

Secondly, even if the NEC allows it, does anyone know any other reason that this would not be allowed?

My thought is that this would be a no-no, because of the unpredictable nature of the salt water beach.

I appreciate any information or opinions on this.

Thanks!

Andrew

Take a look at Article 555

 

[petersonra]

Take a look at Article 555

Article 555 would appear to specifically exclude this type of installation from the requirements found in this article.

 

[buzzbar]

Take a look at Article 555

I should have prefaced this by saying that I have a lot of experience with wiring marinas and docks. So I'm very familiar with Article 555. I don't see anything in Article 555 that pertains to installing conduit in a trench, on a beach. But if I'm missing something, please let me know.

Thanks.

 

[petersonra]

Hi all,
from a house on shore, out to a dock. The easiest path is to dig a trench along the beach, at the highest point.

I should have prefaced this by saying that I have a lot of experience with wiring marinas and docks. So I'm very familiar with Article 555. I don't see anything in Article 555 that pertains to installing conduit in a trench, on a beach. But if I'm missing something, please let me know.

Thanks.

Private, noncommercial docking facilities constructed or
occupied for the use of the owner or residents of the associated
single-family dwelling are not covered by this article.

It would appear that the article itself specifically excludes your situation anyway.

 

[Hv&Lv]

I should have prefaced this by saying that I have a lot of experience with wiring marinas and docks. So I'm very familiar with Article 555. I don't see anything in Article 555 that pertains to installing conduit in a trench, on a beach. But if I'm missing something, please let me know.

Thanks.

I can't see it either. I have wired a couple of boat lifts, and used a "U" conduit to get to the other pole with the second lift motor. We get the conduit deep enough by agitation rather than digging. They are under water, and the inspector hasn't had a problem with one yet. I did fail one, it was failed for box fill, not conduit underwater though.. Would the trench in the beach be any different?

When you think about it, all underground conduits will be full of water eventually.

 

[buzzbar]

I guess there are two things that I would worry about. One, with it being on a tidal beach, the level of the ground could fluctuate enough to "bring the conduit up" to a shallower depth. And two, the fish and wildlife people might not want anything disturbed on the beach. This is in Puget Sound, and they are VERY strict.

 

[Hv&Lv]

I guess there are two things that I would worry about. One, with it being on a tidal beach, the level of the ground could fluctuate enough to "bring the conduit up" to a shallower depth. And two, the fish and wildlife people might not want anything disturbed on the beach. This is in Puget Sound, and they are VERY strict.

I would say this is something that needs to be discussed with the AHJ and the fish and game department. IMO the NEC is satisfied. Pugent Sound may not be satisfied and would need to be asked.

 

[cadpoint]

Frankly, since you are so use to this work, I can't believe you don't know of more of the requirements of your area for your application. In NC building and appling things on a water front requires submittal's to various authorities and it's all depending on exactly what one wants to do.

Let me Vote with Hv&Lv!

You could follow the tidal charts to excute more of your work in a timely manner. One could easily one up, two up the actual type of wire that will be in your raceway, but it will be the customer that needs to understand this differences in price. I believe that's there's even Jacketed (sealed) stuff out there.

Why not put a P trap type PVC run on the down line side at the transition point from roots to beach, if your putting in a mid-pull point....

What do I know

 

[buzzbar]

Frankly, since you are so use to this work, I can't believe you don't know of more of the requirements of your area for your application. In NC building and appling things on a water front requires submittal's to various authorities and it's all depending on exactly what one wants to do.

Let me Vote with Hv&Lv!

You could follow the tidal charts to excute more of your work in a timely manner. One could easily one up, two up the actual type of wire that will be in your raceway, but it will be the customer that needs to understand this differences in price. I believe that's there's even Jacketed (sealed) stuff out there.

Why not put a P trap type PVC run on the down line side at the transition point from roots to beach, if your putting in a mid-pull point....

What do I know

Well, you don't even know me, so how could you be surprised by what I know or don't know? The fact is, I've never had to run a conduit on a beach. Period. Article 555 says nothing about beaches. Period. And apparently, the NEC says nothing about beaches either. So I was looking to see if anyone has had some real world experience with this.

Also, perhaps I wasn't clear, but the location on the beach only goes underwater on rare occasions in the winter, so digging the trench won't be a problem.

I have since placed a call to my AHJ, I'll let everyone know what he says.

 

[cadpoint]

We are Blessed that we know what to do in an average day in respects to some Electricial Application, while a wild Card may be dealt in dealing with things, if it is a pain in expressing it, or presenting it causes one more pain than don't present.


I Wish I rode more of the Tide and knew more things "ALL WET"!

 

[buzzbar]

We are Blessed that we know what to do in an average day in respects to some Electricial Application, while a wild Card may be dealt in dealing with things, if it is a pain in expressing it, or presenting it causes one more pain than don't present.

Are you saying that shouldn't have asked my question? Isn't that what this forum is for? :blink:

 

[cadpoint]

Sir:

Let's say that as a technician, you know the variables or don't!

I frankly don't know how to say it otherwise.

 

[CIECO]

What is the problem

What is the problem

Is it just everyone is hot and tired or just thinks anyone asking a question and not answering a question is an idiot? I have gotten a lot of info from this forum but am sick of the sarcasm if you ask a question that is a little off or your spelling or grammar isn't right. We all don't have are masters or even high school diplomas. I thought this forum was to help one another interpret the code.

 

[buzzbar]

Is it just everyone is hot and tired or just thinks anyone asking a question and not answering a question is an idiot? I have gotten a lot of info from this forum but am sick of the sarcasm if you ask a question that is a little off or your spelling or grammar isn't right. We all don't have are masters or even high school diplomas. I thought this forum was to help one another interpret the code.

Very well said, thank you. Like you, I have learned a lot on this forum, and I've been in the industry for 26 years. You never stop learning.

I will continue to ask questions, and offer advise when I think it will help.

 

[Hv&Lv]

Very well said, thank you. Like you, I have learned a lot on this forum, and I've been in the industry for 26 years. You never stop learning.

I will continue to ask questions, and offer advise when I think it will help.

Quite frankly, I have never thought of trenching on a beach and installing power. I'm sure it is done, but not by many.
Don't get too mad, I liked the question and am interested in the outcome.
How many here have ever ran across a situation where a trench has to be dug on a beach? It isn't an everyday occurrence...
Honestly, if I had a job to trench a beach, I would have to ask a few questions. I bet many on this forum would have to also.

 

[buzzbar]

Quite frankly, I have never thought of trenching on a beach and installing power. I'm sure it is done, but not by many.
Don't get too mad, I liked the question and am interested in the outcome.
How many here have ever ran across a situation where a trench has to be dug on a beach? It isn't an everyday occurrence...
Honestly, if I had a job to trench a beach, I would have to ask a few questions. I bet many on this forum would have to also.

Thanks. I'm not mad, I'm just sort of dumbfounded when I ask an honest question, and I'm answered with, "you should already know that. Now go about your business". It's all good though, life is too short to worry about such things.

I'll let everyone know what my AHJ says tomorrow.

Cheers!

 

[CIECO]

Good let us know. By me one good size storm and we can loose alot of beach.

 

[arnolds]

Chech out 344-10(b)1 and paint the rigid pipe with bitumastic

 

[paul]

It would appear that the article itself specifically excludes your situation anyway.

By the NEC you are correct, however the Washington Administrative Code includes this situation.

WAC 296-46B-555

Special occupancies — Marinas and boatyards.
(1) For the purposes of NEC 555.1, the scope of work includes private, noncommercial docking facilities.

(2) For the purposes of NEC 555.5, transformer terminations must be located a minimum of twelve inches above the deck of a dock (datum plane requirements do not apply for this section).

(3) For the purposes of NEC 555.7, adjacent means within sight.

(4) For the purposes of NEC 555.9, all electrical connections must be installed a minimum of twelve inches above the deck of a pier unless the connections are approved for wet locations (datum plane requirements do not apply for this section).

(5) For the purposes of NEC 555.10, all enclosures must be corrosion resistant. All gasketed enclosures must be arranged with a weep hole to discharge condensation.

(6) For the purposes of NEC 555.11, gasketed enclosures are only required for wet locations.

(7) For the purposes of NEC 555.13, the following wiring methods are allowed:

(a) All wiring installed in a damp or wet location must be suitable for wet locations.

(b) Extra-hard usage portable power cables rated not less than 75?C, 600 volts, listed for wet locations and sunlight resistance and having an outer jacket rated for the environment are permitted. Portable power cables are permitted as a permanent wiring method under or within docks and piers or where provided with physical protection. The requirements of NEC 555.13 (B)(4)(b) do not apply.

(c) Overhead wiring must be installed at the perimeter of areas where boats are moored, stored, moved, or serviced to avoid possible contact with masts and other parts of boats.

(d) For the purposes of NEC 555.13 (B)(5), the wiring methods of Chapter 3 NEC will be permitted.

(8) For the purposes of NEC 555.19, receptacles must be mounted not less than twelve inches above the deck surface of the pier or dock (datum plane requirements do not apply for this section). Shore power receptacles that provide shore power for boats must be rated not less than 20 amperes and must be single outlet type and must be of the locking and grounding type or pin and sleeve type.

(9) For the purposes of NEC 555.21 (B)(1), delete exception No. 1 and No. 2 and replace with:

Dock, pier, or wharf sections that do not support fuel dispensers and may abut a section(s) that supports a fuel dispenser(s) are permitted to be unclassified where documented air space between the sections is provided and where flammable liquids or vapors cannot travel to these sections. See NEC 500.4(A) for documentation requirements.