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Type NM-B Pulled In Before Building Dried In.

mark handler said:
All the BO is asking for is Proof, The Manufacturer will not say that, show me....
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I can tell you from empirical experience and seeing nm cable getting wet, sitting in pickups and never having issues with it. I will also tell you that I saw nm cable used underground to a shed and it was there for 20 years and I bet it is still there. I have no proof but the NEC states in its definition that dry location does not mean the occasional wetness from a building under construction. That should be enough to allow it. I generally don't wire unless there is a roof on but I have seen many houses where the roof was supposedly dried in and rain was everywhere--- the houses are still there along with the wiring after 30 years or more.
 
Somewhere along the line there must have been enough failures caused by the cable getting wet. How is one to know if the cable has been too wet for too long? The manufacturer won't back the practice so I wouldn't expect a jurisdiction to roll the dice.

Dennis pointed out that he has seen NM get way wet and survive. I respect his opinion.

You guys have seen the funky electrical messes that I find. Imagine all of the messes that I haven't found. Each one is a bundle of violations. They have been out there humming along for years, mostly without incident.
 
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Here is what Southwire states: How is that different from what the NEC states

Southwire's Romex SIMpull Type NM-B (nonmetallic-sheathed cable) may be used for both exposedand concealed work in normally dry locations at temperatures not to exceed 90°C (with ampacity limited

to that for 60°C conductors) as specified in the 2011 National Electrical Code. NM-B cable is primarily

used in residential wiring as branch circuits for outlets, switches, and other loads. NM-B cable may be

run in air voids of masonry block or tile walls where such walls are not wet or damp locations. Voltage

rating for NM-B cable is 600 volts
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I think NM manufacturers continue to use that kraft paper packing to insure this is a dry location product and not to cannibalize their UF product business. That is probably why NM-C disappeared too.
 
gfretwell said:
I think NM manufacturers continue to use that kraft paper packing to insure this is a dry location product and not to cannibalize their UF product business. That is probably why NM-C disappeared too.
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Could well be true. Yet another reason to say yes...how about no? There is no definitive answer. Erring on the side of caution will prevail.
 
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gfretwell said:
I think NM manufacturers continue to use that kraft paper packing to insure this is a dry location product and not to cannibalize their UF product business. That is probably why NM-C disappeared too.
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I disagree with that. They used to use a plastic piece instead of paper. Not sure why one is used over the other. How does using paper ensure that it is to be used in dry location. The product itself is listed for dry location so that don't need a fail safe. Again normal dry and IMO it is allowed to get wet during construction. Of course it is always an authority having jurisdiction call but I have seen more water and dampness under a house then one would ever see during construction. I have seen water dripping off the nm under the house and this was years after the house was built.
 
110510_tf_electricalfire.jpg


Let see moisture/electrical Arcing....
 
mark handler said:
110510_tf_electricalfire.jpg
Let see moisture/electrical Arcing....
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And that has nothing to do with NM cable. I also have receptacles and switches on my screen porch in NC that have been there for 25 years without incident and they have standard covers-- not wp covers.
 
It looks like a loose connection and then maple syrup. Knowing how it got that way isn't easy from just a picture. It appears to be aluminum wire.
 
One indicater that it could be moisture related is the location of the burn, which appears to be inside the outlet itself. There does not appear to be any wire to wire arching. Sonic there were moisture inside the outlet case, that's where the arc would be. On the inside.

That's what it looks like to me, as you can see internal parts.

Brent
 
Looks like more of a poor connection between the blade of the plug and the receptical that overheated with the ground prong in the up orientation melting and charring the plastic. Arc fault would have stopped it from getting that far.
 
jar546 said:
So you are saying that the photo looks like it has a loose connection then water was introduced into the loose connection? Please clarify.
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That is exactly what I am saying. I have seen many outlets like that and it was always due to a bad connection. Moisture can cause issues but I seriously doubt that was due to moisture alone.

If a connection is tight there should not be any arcing. I also agree it looks like aluminum wire on there in which case the oulet may not even be rated for aluminum
 


This was taken from an IAEI publication that I received in a class today. General Cable provided the class and the presenter was Cristel Hunter. She is a senior field applications engineer. I asked her about NM in a house under construction. General Cable no longer makes NM. She said that the decision to allow NM in a house under construction is a jurisdiction dilemma.
 
My Grandfather hauled romex,seu,thhn,sj,sjo,pvc,emt,bx,rigid,and every conceiviable box/fitting in the back of a pickup for 40 years and so did my dad. I was first gen to have a cargo van. Neither were "cowboys" always had the customer first. I have romex in the ground at my house,and 500ft of it down to my well pump cause its all I could afford at the time. It was changed out after 20 yrs only due to lighting destroying my pump. With that all said, now that I inspect work-the issue sounds like a ****in contest,but hey I am learning fast to never say "what if" when talking code enforcement. It has bit me already! I am amazed at the forensic investigators around this site for sure....
 
I never said/posted that this was a result of moisture.....It is possible that moisture damaged wire could cause something like this.
 
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What to do with water-immersed Type NM-B nonmetallic-sheathed cable?

By Austin Wetherell & Chuck Mello

Type NM-B nonmetallic-sheathed cable (commonly called "Romex®" in the industry) is Listed by Underwriters Laboratories Inc. for use in accordance with the National Electrical Code® (NEC®) under the product category "Nonmetallic-sheathed Cable (PWVX)." Guide Information for this category can be found in UL's Online Certifications Directory and on page 249 of UL's 2008 Guide Information for Electrical Equipment - The White Book.

Decades ago, the outer jacket of this cable changed from an impregnated, braided covering to polyvinyl chloride (PVC). In the mid-1980s, the internal conductor insulation went from a 60 C to a 90 C rating, and the required marking was changed from "Type NM" to "Type NM-B."

Section 334.10(A)(1) of the NEC states that Type NM cable shall be permitted for use in "normally dry locations." Article 100 of the NEC defines a dry location as:

Location, Dry. A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction.

The older, braided jacketed version of this cable has less resistance to water ingress than the newer, PVC jacketed version, and if subject to immersion, such as from flooding, the suitability for continued use is unknown. Any cable of this type that has been subjected to flooding should be replaced without question.

In general, cables with PVC insulation and jacket can withstand immersion in clean water for a short period of time without being damaged as long as the ends are not immersed. For example, a building may be subject to rainfall while under construction, and water may come in contact with the outer jacket of nonmetallic-sheathed cable. This is not prohibited by the NEC. The UL Standard for Safety for Nonmetallic-Sheathed Cables, ANSI/UL 719, requires Dielectric Voltage-Withstand Tests after 24-hour water immersion of cable samples (with ends in free air). If the ends of the cable are immersed for any period of time, however, the internal paper wrapping around the bare equipment-grounding conductor will absorb and transfer the water into the cable assembly. The water may then start degrading the insulation or possibly corrode the conductors. If the cable comes into contact with contaminated water, the contaminants may also act on the insulation or conductors. Over time, failures can occur.

In a flooding situation, there is no way of knowing how long the cables were immersed in water, or what types of potentially corrosive substances may have been in the water that flooded the cables. As was widely reported after Hurricane Katrina, raw sewage and chemicals were known to be in the floodwaters afflicting the Gulf Coast region of the United States. Nonmetallic-sheathed cable has not been investigated by UL for this type of exposure. Therefore, it is not possible for UL to state that cable in a particular installation is acceptable for continued use after having been subjected to the flooding.

The safest approach is to replace any nonmetallic-sheathed cable that was immersed in water for any period of time during the flooding.

For more information on Type NM-B nonmetallic-sheathed cable, contact Tom Cybula in Melville, N.Y., by phone at 631.271.6200, ext. 28259; or by e-mail at Thomas.H.Cybula@us.ul.com.

After reading this I have had two 1 foot pieces of NMB standing upright in a glass of water to see how long it takes to wick to the top.
 
Not an electrician but I think the answer is in the definitions

From the 2002 NEC Definitions

Location, Damp. Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture. Examples of such locations include partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold-storage warehouses.

Location, Dry. A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction.



Location, Wet. Installations under ground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather.
 
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