What type of conductor for conduit filled with water?

[220/221]

I just don't see how the submerged makes a difference.

If the insulation fails conductor(s) in a dry underground PVC, there is a good chance that nothing will happen. If the conduit is full of dirty conductive water, it increases the chance for a fault.

 

[RHJohnson]

Not knowing your exact situation, but I'd try the submarine (submersible pump) cable.
We have put in miles of u.g.conduit over the years - always try to get it to drain. Not easy, but you won't be replacing bad cables in 5 years.

 

[ptonsparky]

I believe freezing is most likely the culprit. Helps to bury below the frost line.

Pierre's pictures show why conduits should be installed to drain. Drill weep holes in boxes, cut gaskets in LBs, and - egads - use flexible metal conduit outside. I have used it in the past but stopped since it became a such big no no. Installed much as a drip loop, from conduit/enclosure to bottom of motor, they both drain.

 

[JohnE]

Can you find it in 310.13 or 400.4? Because if it is not in those tables I can not use it.

BTW, often 'well cable' is unjacketed.

I can't use that either, it's not in the NEC.

What is the designation of that well cable, Bob?

 

[mivey]

...it ain't worth arguing about...

If that's the way you feel, then I can probably send you a list of links that you might want to avoid. :grin:

 

[kkwong]

If that's the way you feel, then I can probably send you a list of links that you might want to avoid. :grin:

It might be easier to send him a link of those he can go to :grin:

To the OP-I have never been failed either for installing THHN/THWN in an underground run and like most runs they do fill with water. It is possible that the wire was damaged during installation. I would ask the AHJ who failed you for the code section/s. I have also used submarine wire on occasion but have had to argue my case in certain instances with the AHJ or at plan review because it is not something they are used to seeing installed for anything other than pumps.

 

[weressl]

Let's not loose sight of the fact that the OP said the cable failed after 5 years. I really don't think that thermoplastic will disintergrate after 5 years. I have seen TW wire used as well cable for years- 20 years or more. The pumps fail before the wire does. I just don't see how the submerged makes a difference.

Carl, your point is well made. Freezing inside the pipe makes the most sense.

BTW. The wire bob shows , I believe , is TW

Depends what is in the water.

Unjacketed TW Wire? Not part of a cable assembly? Continously submerged?

 

[cschmid]

coulter said it correctly..if you are not going to put in a drain point then you need to do extra maintenance regularly..

 

[don_resqcapt19]

Unjacketed TW Wire? Not part of a cable assembly? Continously submerged?

It is RHW or XHHW and listed for the purpose.

Submersible Water Pump Cable ? Indicates multiconductor cable in which two, three or four Type RHW, RHW-2, XHHW or XHHW-2 conductors are provided in a flat or twisted assembly. The cable is Listed in sizes from 14 AWG through 500 kcmil copper, and from 12 AWG through 500 kcmil aluminum or copper-clad aluminum. The cable is tag marked "For use within the well casing for wiring deep-well water pumps where the cable is not subject to repetitive handling caused by frequent servicing of the pump units." The surface of the wire may also be marked "Pump Cable." The cable has not been investigated for direct burial in the earth unless the single conductors carry an additional "Type USE" or "Type USE-2" marking.

The quote is from the UL Guide information for "thermoset insulated wire" (ZKST)

 

[Smart $]

It is RHW or XHHW and listed for the purpose.

The quote is from the UL Guide information for "thermoset insulated wire" (ZKST)

The "cable assembly" is listed for submerged usage, not the individual conductors or types used therein.

 

[don_resqcapt19]

The "cable assembly" is listed for submerged usage, not the individual conductors or types used therein.

While that is a correct statement, this cable assembly is nothing more than "triplexing" the single conductors.