insulation of conductors inside MN cable

[retire09]

Do you know what the insulation type is for the individual conductors inside NM cable?
I thought it used to be stamped on the cable or the box as THHN and THWN.
Was I dreaming?
Was that true?
Has that changed?

 

[bphgravity]

I do not have my UL marking guides in front of me at this moment however I believe NM cable is only required to have insulated conductors with a 90?F rating as identified in Table 310.13 and be marked as "NM-B". See 334.112 of the NEC.

 

[barbeer]

nm-b cable has thhn insulated conductors

 

[Rockyd]

nm-b cable has thhn insulated conductors

Thank you, if this is the case, then that explains why romex is can't be in a wet location!

 

[don_resqcapt19]

barbeer,

nm-b cable has thhn insulated conductors

Can you cite a document that says this? There are no markings on the conductors and the UL standard only requires the use of 90C conductors without specifiying the type. I agree that they appear to be THHN.
Don

 

[allenwayne]

This from southwire site.Although they don`t list the conductors in NM as being thhn the description is the same

http://www.southwire.com/processGetArticle.do?commonId=b06660f3b370ff00VgnVCM1000002702a8c0____

 

[bphgravity]

Unless you are just trying to satisfy curiosity, it doesn't really matter what the individual conductors are insulated with. The cable is an assembly and the individual conductors cannot be used without its sheathing.

I constantly find NM installations in outdoor raceways, and upon re-inspect I find the installer simply withdrew the conductors from the sheathing and reused them. Once they are withdrawn they are useless, unless you plan on stripping the insulation and using them as equipment grounds?

 

[barbeer]

Don.......

Such a wealth of info the internet is! Check out:

http://appprod.southwire.com/Produc...dyPage=/tab_prodcat.jsp&label=Product Catalog

http://appprod.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet6

These two links are for southwire, I am sure there are others. You are what I can see correct about the non thhn insulation. The conductors are rated for 90 deg. Celcius though....but, if I read right they say to use the 60 deg. C column? A little confusung.

The hyperlink thingy is not working right? WEll......Maybe it is?

 

[stickboy1375]

Unless you are just trying to satisfy curiosity, it doesn't really matter what the individual conductors are insulated with. The cable is an assembly and the individual conductors cannot be used without its sheathing.]


How do I meet 6" of free wire in a box then?

 

[bphgravity]

How do I meet 6" of free wire in a box then?

When you make a joke on the Forum, its best to indicate it's a joke or add a funny little face at the end of the joke. Otherwise, people may think you are actually being serious...

 

[stickboy1375]

who says I was making a joke? You just said I can't use the wire without the sheathing...

 

[bphgravity]

Oh, I'm sorry. I thought your comment was pretty funny...

Obviously, the context of my post was in regard to conductors withdrawn from the cable assembly and used as individual conductors in a raceway or other wiring method. I think you would agree this procedure would not be code compliant, whereas the free conductors of a cable assembly exposed within an enclosure or box would be completely acceptable.

I am truly soory for you confusion...

 

[stickboy1375]

I was kidding, but seriously if that conductor is thhn/thwn, then why a problem with removing the sheath? The only problem I see is the romex is not labeled....

 

[infinity]

I was kidding, but seriously if that conductor is thhn/thwn, then why a problem with removing the sheath? The only problem I see is the romex is not labeled....

That is the problem. You may be able to use the wire from inside of a piece of MC cable since some manufacturers use conductors that are labeled.

 

[allenwayne]

I was kidding, but seriously if that conductor is thhn/thwn, then why a problem with removing the sheath? The only problem I see is the romex is not labeled....

Not much different from using the conductors from a leftover piece of SER for a service.They have no markings so they can`t be used.

 

[RampyElectric]

I read on a manufacturers website that they used THHN in their NM-B product. The fact of the matter is it could be any insulation, but since the wires arent marked/labeled, they might as well be pink elephants outside their sheathing. As for the original question, was it EVER labeled inside NM cable....no clue. Although, I have purchased MC recently and it was marked THHN. Be careful with bph, he is rarely incorrect. Trust me

 

[JohnJ0906]

See 310.11 Marking (I had to look it up myself)

 

[RampyElectric]

so does that mean 310.11A4 is saying that NM cable CANNOT have individual conductors labeled?

 

[JohnJ0906]

As I read and understand it, it means the conductors inside the romex cannot be used by themselves because they are not indiviually marked. If they were individually marked, then, IMO, they could be used without the jacket.

 

[stickboy1375]

Thats the way I read it also...