Install Type NMB before building is dried in

[StevenLeuck]

We have a 7 story building we're working on. It is PT slab construction up through the 2nd floor deck. From their the rest of the project will be wood frame construction. The GC is asking us to investigate ways to speed of the schedule during construction. We know that inspectors frown or even flat out turn down Type NMB cable that is installed before the building is "dried in" with a roof and exterior cover. On the other hand, my business partner recollects some long time ago a project he worked on where the inspectors were convinced via a letter from a manufacturer (Southwire, Essex, etc) that as long as the cable had ample time to dry out before being enclosed or energized that it would be ok for it to be installed after being wet before the building was dried in.

Is anyone else here familiar with any sort of exception like this -- particularly in the form of manufacturer information of this sort? I have requested our cable rep to look into it but while I waited on that I was hoping someone possibly on this forum may also be familiar with an exception which we may be able to successfully argue our case to the local AHJ.

Thank you.

Steven Leuck
Oregon

 

[Dennis Alwon]

As I read the NEC it states that nm cable shall be installed in normally dry locations. An inspector could cite that article however in my opinion it is normally dry as long as it isn't exposed for long periods of time. I would not install panels recessed cans or fans until it is dry.

NM sits in the back of pickup trucks getting wet all the time. I have never seen an issue with it especially if it is not immersed in water however it will be an authority having jurisdiction call.

 

[texie]

As I read the NEC it states that nm cable shall be installed in normally dry locations. An inspector could cite that article however in my opinion it is normally dry as long as it isn't exposed for long periods of time. I would not install panels recessed cans or fans until it is dry.

NM sits in the back of pickup trucks getting wet all the time. I have never seen an issue with it especially if it is not immersed in water however it will be an authority having jurisdiction call.

I agree. And apparently so does Southwire as they have published a paper on this as I recall. I'll have to track it down.

 

[pjholguin]

I have a question: When did the code change to allow type NMB cable in buildings greater than two stories? I have been in the industrial setting for quite a few years now, and when I was doing residential NMB was not allowed in buildings greater than two stories. Also at that time the inspectors in my area would not allow any dry location rated material installed till the building was dried in.

PJHolguin

As I read the NEC it states that nm cable shall be installed in normally dry locations. An inspector could cite that article however in my opinion it is normally dry as long as it isn't exposed for long periods of time. I would not install panels recessed cans or fans until it is dry.

NM sits in the back of pickup trucks getting wet all the time. I have never seen an issue with it especially if it is not immersed in water however it will be an authority having jurisdiction call.

 

[texie]

I have a question: When did the code change to allow type NMB cable in buildings greater than two stories? I have been in the industrial setting for quite a few years now, and when I was doing residential NMB was not allowed in buildings greater than two stories. Also at that time the inspectors in my area would not allow any dry location rated material installed till the building was dried in.

PJHolguin

This change was made in the 2008 cycle. The use of NM is now governed by the building construction type rather than the height. As I recall, the prohibition of NM cable above a suspended ceiling, in other than a residential occupancy, came at the same time.

 

[DBoone]

http://forums.mikeholt.com/showthread.php?t=134685

 

[StevenLeuck]

Sure appreciate the responses so far. If anyone knows of the manufacturer declaration that one of you mentioned, that would be fantastic.

Thank you.... looking forward to more info if anyone has it. The more ammunition to present to the AHJ the better.

sL

 

[stickboy1375]

Why not just site the definition? 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.


This solves any issues with 334.12 (B)(4)

 

[jaylectricity]

I'm less concerned with the wire than I am with the nail-on boxes. The order I use is mark locations, bang up boxes, drill holes, run wire, prepare boxes for trim.

The wire is plastic and non-ferrous materials. The nails on the boxes are steel and start to rust after even a foggy night.

 

[stickboy1375]

I'm less concerned with the wire than I am with the nail-on boxes. The order I use is mark locations, bang up boxes, drill holes, run wire, prepare boxes for trim.

The wire is plastic and non-ferrous materials. The nails on the boxes are steel and start to rust after even a foggy night.

How many boxes have you had fall off the studs? :slaphead:

 

[jaylectricity]

How many boxes have you had fall off the studs? :slaphead:

I haven't been alive long enough to find out.

 

[fmtjfw]

I'm less concerned with the wire than I am with the nail-on boxes. The order I use is mark locations, bang up boxes, drill holes, run wire, prepare boxes for trim.

The wire is plastic and non-ferrous materials. The nails on the boxes are steel and start to rust after even a foggy night.

Pull the supplied nails and replace them with the same size galvanized nails

 

[iwire]

Why not just site the definition? 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.


This solves any issues with 334.12 (B)(4)

No, the defintion of dry location does not mean you can install NM and let it get wet.

That defintion simply prevents any AHJ from claiming an area that got wet during construction is a wet location requiring wet location methods.

 

[iwire]

Check out the end of 110.11

110.11 Deteriorating Agents. Unless identified for use in the operating environment, no conductors or equipment shall be located in damp or wet locations; where exposed to gases, fumes, vapors, liquids, or other agents that have a deteriorating effect on the conductors or equipment; or where exposed to excessive temperatures.

FPN No. 1: See 300.6 for protection against corrosion.

FPN No. 2: Some cleaning and lubricating compounds can cause severe deterioration of many plastic materials used for insulating and structural applications in equipment.

Equipment not identified for outdoor use and equipment identified only for indoor use, such as ?dry locations,? ?in-door use only,? ?damp locations,? or enclosure Types 1, 2, 5, 12, 12K, and/or 13, shall be protected against permanent damage from the weather during building construction.

 

[GoldDigger]

Directly on point. Which brings us back to the manufacturer's evaluation of whether limited exposure to moisture will cause permanent damage. Without that we are forced to assume the worst.

Sent from my XT1080 using Tapatalk

 

[don_resqcapt19]

This change was made in the 2008 cycle. The use of NM is now governed by the building construction type rather than the height. As I recall, the prohibition of NM cable above a suspended ceiling, in other than a residential occupancy, came at the same time.

The "3 story" limit for NM was removed in the 2002 code and the suspended ceiling limitation was added at the same time.

 

[StevenLeuck]

I agree. And apparently so does Southwire as they have published a paper on this as I recall. I'll have to track it down.

Texie, Were you, perchance, able to find the publication from Southwire you may have had at one time? The suggestions and references here have all been great. I also found an article/brochure from UL Labs talking about what to do in the event of a "Katrina-like" catastrophe in regards wiring and electrical apparatus. They specifically mention that NMB with PVC sheathing is normally OK for temporary exposures to severe weather as long as the ends aren't soaked through. If you actually had something from Southwire or any other cable manufacturer -- that would be even better.

Steven Leuck

 

[stickboy1375]

No, the defintion of dry location does not mean you can install NM and let it get wet.

That defintion simply prevents any AHJ from claiming an area that got wet during construction is a wet location requiring wet location methods.

Seriously? Is everyone that dumb, that is the reason they added the extra context?

 

[iwire]

Seriously? Is everyone that dumb, that is the reason they added the extra context?

I do not know if it ever happened but if you look at the definition of wet location I think you can see the wet and dry locations could be considered in conflict without the extra wording excluding periods of construction.

Location, Wet. Installations underground 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.

 

[texie]

Texie, Were you, perchance, able to find the publication from Southwire you may have had at one time? The suggestions and references here have all been great. I also found an article/brochure from UL Labs talking about what to do in the event of a "Katrina-like" catastrophe in regards wiring and electrical apparatus. They specifically mention that NMB with PVC sheathing is normally OK for temporary exposures to severe weather as long as the ends aren't soaked through. If you actually had something from Southwire or any other cable manufacturer -- that would be even better.

Steven Leuck

I can't locate the piece I was thinking of but this may help as it is from UL. It clearly points out that incidental water contact is not an issue. Look here: http://www.ul.com/global/eng/pages/.../electrical/additionalresources/flooding/nmb/
Is this the same piece you found?
I might add that I know of a fair number of AHJ's that insist on full dry-in before NM cable is installed. Many even have definitions of what is dry-in is. That said, even the UL piece says the NEC does not require this. I think that there is a big difference between installing NM cable that may get a little wet and installing, say, a breaker panel(even without breakers) or a wiring device.