Is there a violation if you used a cable with another conductor or two in a raceway system?
(example a 12-3 w/g Romex and an additional THHN for the 4th ungrounded conductor in a 3/4" raceway).
It didn't sound right when I heard it but I am not sure what you would cite.

That's interesting...
I must say none of the rocket scientists here thought that up....yet!
Time to ponder what (if anything) to cite.

FYI: another reason to add common sense to the NEC?

can you install NM cable in a complete raceway system? Or only in a piece of raceway just for physical protection?

I can't cite any rule that says you can't have NM cable in a raceway system. Since all circuit conductors come through the same connector there are no inductive heating problems. I know this is ugly but I am stumped to come up with a violation.

It's not a violation.

However, due to economics you'd not expect to see it.

It's generally impractical.

I’m wondering if 300.3[B] and 300.3[B],1 might apply if the conductors are all part of the same circuit, since both also state the same "cable or cord" as well.
Something else maybe, is that 334.15[B] is for exposed work, so not sure if this would preclude the NM from being run in a conduit that is concealed or partially concealed.

I suspect the RX was there first and the THHN was added.

KJay, this was all exposed in a garage/shop. A 240 2 pole was converted to 120/240 3 pole from what I could assume.
I see RX in pipe quite a bit, just because that is what resi guys have on the truck or what homeowners buy at the HD. I bet 99% of it is fed into the pipe as they build the system just because of how hard it is to pull RX in pipe.
I think part of it is you can buy RX cheaper than THHN if you don't want 500 feet.

I was not AHJ, just asked if it was legal as "gee whiz" info.

I guess technically you might be able to say that EMT fittings are not designed or listed for use with NM cables, since I see where 300.15 says that fittings and connectors shall be used only with the specific wiring method for which they are designed and listed.

IMO, I don’t think the NEC allowing NM to be sleeved for protection was intended to allow unlimited use like that, but I’m also not sure exactly where to find a specific rule prohibiting it.

Kjay:
The fittings you reference above are EMT, and used on the EMT, not the NM as I understand Gregs description. 300.15 would be a bad cite.

I tend to say there is nothing to directly cite, unless at the begining of the circuit, there is no 'from-to' connector.

True. It was just something to mull over. My thought was that NM is a separate wiring method with its own installation requirements and listed connectors, etc.

Kjay:
I've given this thread thought, read the responses, & gave more thought.

I can't pin an article that I could cite.

Talking with a few inspectors & ECs at a CEU class I did Tuesday, the inspectors had no ideas, and the consensus from the ECs was split. The split was 50% said 'stupidity', the other group said 'it's not something they do'. Now, that they may be aware it's not citable, I'm waiting to see IF anyone tries it.

I have asked this question from a local inspector and he hasn't been able to cite a section.

Niko:
I strongly doubt that any NEC Article could be cited. As long as fill capacity is not exceeded, there is no article to cite.

He tried, 310.15, 310.4 and 300.5 but none apply. i just wanted to see if he had anything to say. I will bring it up on my next IAEI meeting.

Greg,

Is the EMT outside? Then you can cite, no RX is allowed in a wet location.

If the EMT is inside, you can ask the EC for a UL listing for approved use of the RX inside of EMT.

Will you have to derate the conductors because of a cable installed inside of EMT.

I would use an EMT/PVC to protect a piece of cable when running through a floor or along a wall, etc. However my rule of thumb was any length of pipe 10' or less could be used for physical protection, but not over 10'. Then we would just run pipe.

Harold:

To continue this debate, I reply to your comments (IMHO)

Yes, if it is outside then it's a wet location, but the OP did not go there.

Going the UL route may be extreme, but it's a thought.

Derating, as the OP statement is not an issue I think. Greg did not mention any info leaning that way.

Your 10' rule of thumb would also be a tough thing to cite, as I'm not aware of any dimensions within the NEC for physical protection.

Inside
I don't think you can get any code traction on increased heat, derating is only based on the number of current carrying conductors. It doesn't matter if it is a bundle of wire, zip tied together, a cable, 1/2" PVC or 4" RMC)
I also don't find a prohibition of cables in raceways.
In fact note 9 to table 1 in chapter 9 implies you can put cables in raceways and gives you the way to compute fill.


Note 2 makes it clear note 9 is not talking about short sections of conduit used for physical protection.

BTW, They changed the derating tables in 2011.

It used to be based on the number of 'current-carrying conductors' in a raceway. They deleted the phrase 'current-carrying', so conductor sizing will soon be getting a bit trickier.

John,


I guess my 10' rule is just a rule of thumb that can't be quoted from the NEC. As Greg said, the code does allow a "Short piece" of conduit for protection to be allowed. Just how short is short? It would up to the AHJ as to make that call.

Harold:
I know what you mean, and the intent of what you mean. Unfortunatley, I know of an instance of the Board of Appeals not being to appreciative of not having a code article to cite.

Standard trade practices, and workmanlike manner aside, some people have an axe to grind, and they waste their time going to the mat, or the ends of the earth.

The above comments are my opinions, and are not intended for any individuals, either ECs or AHJs.

John,

As you might remember, I sit on the Board of Appeals. So oI would never accept an argument from anyone without a code section to back it up.
As for myself, if someone challenged me on that little 10' rule, I would listen to his side of the argument, and most likely let him do it.

358.22 specifically allows cable to be installed within EMT.

Personally, as an electrical inspector, I would cite 300.3(B) as the code section to disallow this installation. I would argue all the conductors of the circuit were not installed in the same cable assembly; either all THHN [single conductors] are in the same raceway, or all conductors are in the same cable assembly. That is the code section I woulde cite in the correction notice I would write.

You can argue all you want, I wouldn't permit this installation and my boss would back me up.

Dana:
Yes, 358.22 allows cable installed in EMT.

A violation citing 300.3(b) would be taken before the Board of Appeals here, and based on the verbage within said Article, the cited violation will not stand, and the BOA would rule against the AHJ (inspector and/or sub-code official) , and in favor of the EC or homeowner. I'm sure Harold will second this comment.

That all said, as I mentioned in a previous post, this is not a install that I see. (EMT or any type of raceway system with NMC). I also have not yet came upon anyone doing what Greg described within the OP.

I have see it before couple time in Wisconsin and really it was a hard item to back up due the NEC did not excatally describe as you say in first place and I did review the NEC { 2005 and 2008 NEC verison } and I just can not excatally nail it however jump over to Electrique Codé France { Basically a French verison of NEC but used in France } and came up a sweet spot where I found and it say with T&E { twin and earth the same as your NM cable } with extra conductor in raceway is not allowed the only time it will allowed if all indivual conductors.

Merci.
Marc

342.22, 344.22, 348.22, 350.22, 352.22, 356.22, 358.22, 360.22, and 362.22 permit cables to be installed in raceways where the cable articles permit it.
For EMT:
358.22 Number of Conductors. The number of conductors
shall not exceed that permitted by the percentage fill
specified in Table 1, Chapter 9.

Cables shall be permitted to be installed where such use
is not prohibited by the respective cable articles.

The number of cables shall not exceed the allowable percentage fill specified in Table 1, Chapter 9.

For NMB cable: 334.15(B) states:
(B) Protection from Physical Damage. Cable shall be
protected from physical damage where necessary by rigid
metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC conduit, Type RTRC marked
with the suffix -XW, or other approved means. Where passing
through a floor, the cable shall be enclosed in rigid
metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC conduit, Type RTRC marked
with the suffix -XW, or other approved means extending at
least 150 mm (6 in.) above the floor.

Conclusion: NMB cables can be installed in raceways.

Would the cable assembly (RX/BX)inside of a piece of EMT be considered bundling?

You would certainly have to apply derating appropriate to the total number of conductors.

Why would anyone want to put a metal cable inside EMT? I guess it takes all kinds.

"Physical protection"?

Wanted to throw my 2 cents in there. It's OK to sleeve the Romex, but when you reach the panel or box you must use a romex connector. So much for the Romex in the pipe all the way.
The idea of running a third circuit as THHN does not meet the code either.
SJT