Originally Posted By: Dan Weber This post was automatically imported from our archived forum.
(BLUF) Bottom Line Up Front, NM is not designed to be exposed.
Question 1, why and where would you use NM for a surface mounted application  Also where in the code does it say it is acceptable for NM to be surface mounted 
Question 2, why in the picture does it not show any supports for the NM  NM is supposed to be supported within 12" of a metalic box, 8" of a nonmetalic box and 4 1/2' there after.
If you were going to run wire in any of the types of conduit why would you run NM  It dosent make sence to me. Add a junction box to the conduit then run your NM
-- Dan Weber
SSG, US Army
Quality Assurance Inspector
Engineers Lead the Way!
Originally Posted By: jpeck This post was automatically imported from our archived forum.
Dan Weber wrote:
(BLUF) Bottom Line Up Front, NM is not designed to be exposed.
NM can be exposed outdoors if listed as 'sunlight resistant', however, it still needs to be protected from physical damage where susceptible to physical damage.
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
Not outside, and Type NM is not allowed to be used outdoors, and this sketch is showing a typical installation through an interior "Floor" Only Type UF-B that is sunlight resistant can be used outdoors.
Yes, support is required.
PS: Any installation using Type NM would violate the UL listing because it is required to be Type NM-B, at least since the 1984 NEC (around a year after the code was introduced.)
Originally Posted By: jpeck This post was automatically imported from our archived forum.
When we state NM cable, we are referring to non-metallic sheathed cable, not specifically NM or NM-B, but as the code referred to “non-metallic sheathed cable”.
Thus, any reference to specific requirements for NM, or probations for NM, should be considered with that in mind.
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
We? … For the benefit of ALL members this is the Law!!
334.6 Listed.
Type NM, Type NMC, and Type NMS cables shall be listed.
Quote:
334.112 Insulation.
The insulated power conductors shall be one of the types listed in Table 310.13 that is suitable for branch circuit wiring or one that is identified for use in these cables. Conductor insulation shall be rated at 90?C (194?F).
FPN: Types NM, NMC, and NMS cable identified by the markings NM-B, NMC-B, and NMS-B meet this requirement.
Originally Posted By: jpeck This post was automatically imported from our archived forum.
Yes, we. As in HIs and most, if not all, electricians, when referring to:
334.2 Definition.
Nonmetallic-Sheathed Cable. A factory assembly of two or more insulated conductors having an outer sheath of nonmetallic material.
Yes, "NM" means "Nonmetallic-Sheathed Cable" which includes the following.
334.6 Listed.
Type NM, Type NMC, and Type NMS cables shall be listed.
If you will notice, NM-B is not listed in 334.6. NM-B is a type of NM ("Nonmetallic-Sheathed Cable").
Now, when one of us ("we" of most electricians for that matter) state NM-B, "we" actually mean "NM-B".
NM-B is NM with conductors which have higher temperature rated insulation than the OLD, and just plain, NM, HOWEVER, NM-B IS STILL "NM", as shown in 334.6 (quoted above).
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
If you see a cable with "NM" only on it, and it was installed after the rule became effective in the 1984 NEC, it will have violated the requirements.
This is the issue, and that is the reason why I call this to the attention of this forum.
It would be easier if the Code did include the -B everywhere, but the (FPN) Fine Print Note is all that we have.
I don't think that what you are saying is wrong, I am only trying to educate the members here so they will be aware.
Perhaps we should see if the NEC committees would agree to add the -B in the Code, then that would help to avoid the questions.
How many times have you, or any member here found the older type of "NM" cables with 60 degree insulation installed as new cable, maybe for an addition, or new bathroom, etc.?
I have seen that happen because in some areas they don't cite code rules and were not aware of the changes.
Sometimes a review of the Electrical Permits at City Hall will reveal dates, that is if a permit was issued at all.
Originally Posted By: jpeck This post was automatically imported from our archived forum.
Joe,
We (HIs and most electricians) do not call it NM because they see NM on the cable, they just know it as NM, for non-metallic sheathed cable.
Yes, most HIs and electricians do call it RomexTM, however, I have been trying to get everyone to call it NM cable, because that is what it is. RomexTM is like FreonTM, a trademarked name. FreonTM should be referred to as "refrigerant", unless you specifically KNOW that it is FreonTM, and RomexTM should be referred to as NM cable, again, unless you KNOW it is RomexTM.
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
What did you call it? Is this you? Huh?
Quote:
This photo is of improper electric wiring in an attic.
The romex in the attic had been improperly spliced.
There was no junction box protecting the splice. The junction box, when installed, is supposed to be accessible from either the under side (via the ceiling) or close enough to the attic access to allow the junction to be accessed. However, as the practicality of accessible junctions in the attic is very limited, most junctions are made up throughout the attic where ever they happen to occur.
You will also note that there is a lack of support for the romex at or near the junction, when a junction box is installed, it should be solidly mounted to one of the trusses or to a securely mounted cross brace, and not left hanging from the romex.
Originally Posted By: Bob Badger This post was automatically imported from our archived forum.
Dan Weber wrote:
(BLUF) Bottom Line Up Front, NM is not designed to be exposed.
If you mean outside in wet locations you are correct.
If you mean inside in dry locations that is incorrect.
Type NM is clearly allowed to be run exposed by the NEC
Quote:
ARTICLE 334 Nonmetallic-Sheathed Cable: Types NM, NMC, and NMS
334.15 Exposed Work.
In exposed work, except as provided in 300.11(A), the cable shall be installed as specified in 334.15(A) through (C).
(A) To Follow Surface. The cable shall closely follow the surface of the building finish or of running boards.
(B) Protection from Physical Damage. The cable shall be protected from physical damage where necessary by conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit, pipe, guard strips, listed surface metal or nonmetallic raceway, or other means. Where passing through a floor, the cable shall be enclosed in rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit, listed surface metal or nonmetallic raceway, or other metal pipe extending at least 150 mm (6 in.) above the floor.
(C) In Unfinished Basements. Where the cable is run at angles with joists in unfinished basements, it shall be permissible to secure cables not smaller than two 6 AWG or three 8 AWG conductors directly to the lower edges of the joists. Smaller cables shall be run either through bored holes in joists or on running boards.
Originally Posted By: Mike Parks This post was automatically imported from our archived forum.
Joe
"PS: Look in the index of the 1996 and earlier NEC's and you will find "Romex" that directs you to the Article 336 Type NM Non-Metallic Sheathed Cable!"
Do you mean pp 70-1058? 
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Jerry P,
While technically you are correct, Romex is a brand, it is also slang for NM-B cable. While Romex does hold the copyright to the name Romex when used in conjuction for NM-B cable that does not stop the rest of the world from using the name for NM-B cable.
Take Coke for example...you don't see Coca Cola trying to sue those south americans for using the slang word "Coke" when referring to Cocaine, now do you!
Originally Posted By: jpeck This post was automatically imported from our archived forum.
jmyers wrote:
Jerry P,
While technically you are correct, Romex is a brand, it is also slang for NM-B cable.
Joe M.,
It is slang for ANY NM cable, isn't it?
If you see old NM cable (pre-NM-B) don't you still call it romex?
The same for those who refer to it as NM cable.
Pre-NM-B cable and NM-B cable is all NM cable, isn't it?
Romex is NM cable is pre-NM-B is NM-B is non-metallic sheathed cable is NM-C, etc.
That is what I was pointing out to Joe T. when he was trying to pick my reference to NM cable apart as something about 'that should have been NM-B since so-and-so-year.
Whether you call it romex, NM cable, "rope" (as the guys in Chicago call it), you are referring to it in all of its reincarnations, and what "it is" depends on when it was made. Old cloth covered NM cable is still romex to the person who uses the term "romex". They don't care whether it was made 50 years ago or yesterday, it is still "romex". Likewise to those who call it NM cable.
