Is submerged still considered "Wet"?

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sparkyguy545

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I need to install a feeder conduit which will be permanently submerged in a lake. Conduit to be Schedule 80 PVC, conductors will be 4/0 Copper. Article 682.14 talks about Equipment, not feeders. Therefore, I don't' necessarily feel that the Flexible Cords and Cables listed for "W" or wet locations (as referenced back to Table 400.4) would actually apply. Is building wire listed for "wet" locations acceptable such as XHHW-2 or THWN-2 acceptable? Alternately, is something like Submersible Pump Cable necessary? My Source of electrical supply is on shore. Termination will be above water-line at a permanent pumping "platform" located about 500' from shore. Pumping Platform will supply a Municipal Water system. Installation will be a single pull from Dry-Land to Dry-Platform using sweep elbows.
 
This comes up all the time and IMO, the wet location wire is legal however as others pointed out in previous threads, the failure rate seemed to be higher when installed directly in water. In PVC, properly sealed may keep water out but I doubt it.
 
Thx for the response.
Over the years, I've always assumed any underground installation (including handholes & manholes) will frequently be filled with water. I don't care how tight a conduit installation or vault is constructed, nature will always find a way to fill it with ground water. IMHO, anyone that thinks otherwise is kidding themselves or spending a lot of expense on sump pumps. But below-grade is an occasional thing that cycles with seasonal rainfall, etc. A conduit installed under a lake seemed a bit different because it will functionally be flooded 100% of the time. I was intending to use either XHHW-2 or RHW-2 unless I found they were specifically NOT allowed because of some language in either NEC or their UL listing that I've been unable to find. I was hoping either find some concurrence to my opinion or someone to tell me I"m brain-dead and should be using "XYZ Cable Type" and some supporting information as to why.
 
sparkyguy545 said:
But below-grade is an occasional thing that cycles with seasonal rainfall, etc.
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I wouldn't be so sure of that. I've come across plenty of buried PVC conduit that retain considerable amounts of water year-round, even in the summer. Realize that if the conduit run is long, the volume of contained water will be quite large in relation to the exposed surface area (for evaporation). That surface area always be fixed at less than twice the inner cross-sectional area of the conduit (twice for two open ends; less because of the volume of wire in the conduit).

As for water intrusion, the problem isn't always at the joints (after all, PVC pipe can easily be mawatertightite for pressurized water supply lines, even when buried). For electrical conduit, the water often enters via the open ends.
 
? Submerged is definitely “Wet” by Art 100 Definition Location, Wet

? Conductors in Table 310.13(A), column “Application Provisions” for wet locations are acceptable in any raceway suitable for the application.

STRICTLY personal opinion: I prefer thermoset over thermoplastic insulations. I believe the electrical properties are barely adequate for thermoplastics insulations less than 30mils. (JMO)
 
iwire said:
Once water gets in the conduit I don't think it ever goes away. (In most cases)
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You are probably correct. I did one job where I ran almost 200' of 2" pvc. I used the primer and glue and when I came back 2 months later to pull the wire the pipe was bone dry. Now with the wire and condensation I have no idea. I doubt the water will get out if it gets in.
 
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