Thwn

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hardworkingstiff

Senior Member
Location
Wilmington, NC
I had an inspector today tell me that THWN is not rated to be submerged, therefore it is not allowed to be used to wire a boatlift where a PVC conduit runs underwater and up a pole.

I asked him about underground conduits in high water tables and he said it is only wet a few hours a day. Thanks to his boss who would not let him enforce this.

Can anyone offer any insight? Is the inspector correct?
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
I just looked at the UL Wire Marking Guide, the only "submerged" shown is "submersible pump cable":

WMG said:
Submersible Pump Cable ? Indicates multiconductor cable consisting of two or three flat or two to six twisted insulated conductors with or without an overall jacket. The cable is labeled in size 14 AWG to 500 kcmil copper, and 12 AWG to 500 kcmil aluminum or copper-clad aluminum. The cable is tag marked ?For Wiring Only Between Equipment Located at Water Well Heads and Motors of Installed Deep-Well Submersible Water Pumps.? The insulation is surface marked ?Submersible Pump Cable.? The cable has not been investigated for direct burial in the earth.


So, the only wire you can use for an application other than that is a wet-location method, IMO.

I noticed in my flight through that book, resistance to gasoline carried the statement "submerged in gasoline", so I'm thinking submersion in water is peachy for wet conductors. :)
 

barbeer

Senior Member
I have in fact ran the conductor in that application before and would not turn down the installation myself. 310.13 states the insulation is rated for "wet" locations- doesn't get much wetter than that........... I however did use primer and blue glue on my conduit connections for added protection.
 

thinfool

Senior Member
Location
Kentucky
hardworkingstiff said:
he said it is only wet a few hours a day. Is the inspector correct?

Another authority type person with no 'real world' experience.

Things could really move ahead if inspectors had to have:
1. no political connections
2. 10-20 years of experience in the 'trade'.

I know....in heaven. <sigh>
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
hardworkingstiff said:
I had an inspector today tell me that THWN is not rated to be submerged, therefore it is not allowed to be used to wire a boatlift where a PVC conduit runs underwater and up a pole.
I'd ask him what he considers appropriate for the application.
 

woodduder

Senior Member
Location
West Central FL.
The definition of a wet location is subject to saturation with water. There is no time frame mentioned in the definition. THWN is listed for wet locations. Send me the permit and I'll sign it.
 

Smart $

Esteemed Member
Location
Ohio
hardworkingstiff said:
I did, he stated type W cable because it is rated for immersion.
Hmmm... Type W cable is Portable Power Cable:
UL 2006 W&CMG pg. 39-40 said:
PORTABLE POWER CABLE (QPMU)
GENERAL
This category covers portable power cable constructed and Listed for use in accordance with Article 400 of ANSI/NFPA 70, ?National Electrical Code? (NEC). Portable power cable consists of either a single insulated conductor or two or more insulated conductors, with or without grounding conductors, with an overall fiber reinforced jacket. The insulation and jacket are thermoset on Types G, G-GC and W, and thermoplastic elastomer on Type PPE.

This cable is used to supply power to mobile equipment and machinery and is rated 2000 V, 90?C (194?F) dry, and 60?C (140?F) where exposed to oil. For cable so marked, ratings of 60?C (140?F), 75?C (167?F), or 90?C (194?F) ?wet? are also assigned. The term ?wet? indicates that the cable is acceptable for immersion in water. Cable that has been investigated for use where exposed to the direct rays of the sun is marked ?Sunlight Resistant? or ?Sun Res.?

Portable power cable employs flexible stranded copper conductors in a size range of 12 AWG to 500 kcmil, except for single conductor Type W and single conductor Type PPE which employs flexible stranded copper conductors in sizes 12 AWG to 1000 kcmil. Ampacities for portable power cable can be found in Table 400.5(B) of the NEC.
Type G ? Contains 2 - 6 circuit conductors and a grounding conductor. The grounding
conductor is either bare or covered with a green-colored braid or tape, and may either be a single
conductor or be sectioned into two or more parts.
Type G-GC ? Same as Type G except that the cable also contains one, 10 AWG or larger,
yellow insulated conductor which is used as a ground check.
Type W ? Contains 1 - 6 circuit conductors and may or may not contain a grounding conductor.
If included, the grounding conductor is fully insulated.
Type PPE ? Contains 1 - 6 circuit conductors and may or may not contain a grounding
conductor. If included, the grounding conductor is fully insulated.​

ADDITIONAL INFORMATION
For additional information, see Electrical Equipment for Use in Ordinary Locations (AALZ).

REQUIREMENTS
The basic requirements used to investigate products in this category are contained in UL Subject 1650, ?Outline of Investigation for Portable Power Cable.?

UL MARK
The UL symbol on the product and the Listing Mark of Underwriters Laboratories Inc. on the attached tag, coil, reel or smallest unit container in which the product is packaged is the only method provided by UL to identify products manufactured under its Listing and Follow-Up Service. The Listing Mark for these products includes the UL symbol (as illustrated in the Introduction of this Directory) together with the word ?LISTED,? a control number, and the product name ?Portable Power Cable.?

Perhaps a better choice:
UL 2006 W&CMG pg. 31-32 said:
MARINA AND BOATYARD CABLE (PDYQ)
USE
This category covers cable intended for use as flexible branch circuit and feeder wiring in marinas and boatyards in accordance with Article 555 of ANSI/NFPA 70, ?National Electrical Code.?

The cable is rated 600 V, 75?C and is suitable for exposure to sunlight, fresh water, salt water, gasoline, diesel fuel and lubricating oil.

ADDITIONAL INFORMATION​
For additional information, see Electrical Equipment for Use in Ordinary Locations (AALZ) and Marine Products (AAMP).

REQUIREMENTS​
The basic standard used to investigate products in this category is UL 83, ?Thermoplastic Insulated Wire.?

UL MARK​
The UL symbol on the product and the Listing Mark of Underwriters Laboratories Inc. on the attached tag, coil, reel or smallest unit container in which the product is packaged is the only method provided by UL to identify products manufactured under its Listing and Follow-Up Service. The Listing Mark for these products includes the UL symbol (as illustrated in the Introduction of this Directory) together with the word ?LISTED,? a control number, and the product name ?Marina and Boatyard Cable.?
 
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Smart $

Esteemed Member
Location
Ohio
hardworkingstiff said:
Smart $,

Do you know where to locate PDYQ cable? I tried and was unsuccessful.
I suppose it would help if someone actually made the stuff :smile:

UL only shows one company having PDYQ certification:

Coleman Cable, Inc

However, I did not find any such cable on their website. Perhaps you should contact them directly.

Amercable seems to maunfacture cable of the sorts, but their products are listed under other categories (search Amercable for company name) — Portable Power Cable for one.

[Addendum] I wonder what the inspector would have said if you used continuous hdpe (that I suggested in other thread), rather than pvc???
 
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acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
I asked him about underground conduits in high water tables and he said it is only wet a few hours a day. QUOTE said:
That is ignorant. I have seen many underground conduits that are never dry. They are always full of water "submerged" in the pipe. I think you should ask if "WTF" cable would be acceptible.
 

dcspector

Senior Member
Location
Burke, Virginia
I agree, I would have tipped my hat, said have a great day, and signed off on the permit. The NEC does not say one cannot use HDPE submersed in water but the fiber optics guys are. Common sense would tell one that it is a "continuous" conduit. Also, I would have passed THWN in pvc under water and then emerge...as the OP installed. Am I crazy?
 
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