Romex in conduit

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I was wondering if there is any restriction to installing romex wire in conduit?
The code states you can do it for physical protection. So is there any ruling against running it in conduit when there is no need for protection?

Thank you for your help
 
The short answer is that, if your conduit is run box-to-box, it's a conduit system and should be filled with individual conductors, not NM.
 
brother said:
no there is not
just dont over crowd, as it would create heat. :)
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I don't know if it would not matter if it was type NM cable or type Thhn as far as overheating goes. You can get alot more building wires in a conduit than type NM cable. I am not sure but it seems like you can only get 3-12/2 romex's in a 3/4" EMT conduit. The most you would have would be 6 current carrying conductors if this was so. It seems like also romex would have more insulation to help deter the heat compared to building wire. I have been told you rate type NM cable on the 60% temp scale of the amperage chart so the rating might be lower than regular type Thhn wire.
 
See all the 3xx.22 articles.

For example;

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.
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Roger
 
But if you do put NM in conduit don't forget about Chapter 9, Table 1, Note 9.
(9) A multiconductor cable of two or more conductors shall be treated as a single conductor for calculating percentage conduit fill area. For cables that have elliptical cross sections, the cross-sectional area calculation shall be based on using the major diameter of the ellipse as a circle diameter.
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Also if you are still using the 2002 code, the issue is not as clear. The wording in the .22 section of the raceway articles was different.
344.22 Number of Conductors.
The number of conductors or cables 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 permitted by the respective cable articles. The number of cables shall not exceed the allowable percentage fill specified in Table 1, Chapter 9.
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Don
 
I've got a question for the original poster. If you don't need it for protection, why would you do it in the first place?
steve
 
Were the question arose from

Were the question arose from

An inspector said that it was against the NEC to run romex in conduit. Article 334.15 (B) says it can be done. The inspector could not find were in the code it says you can not install romex in conduit. If the NEC says you can do it for physical protection then would'nt that mean that romex has to be UL listed to be run in conduit? this is what started the question at hand.
 
An NRTL (UL for one) wouldn't come to play here, it is simply as posted. Have the inspector read 358.22 (2005) and then tell him to read article 334 to see if he can find where it is prohibited.

Even in earlier cycles it is not prohibited, (we don't all agree here though) see Don's post.

Roger
 
Roger,
Where is the exception from the requirements of 334.30 when the NM is installed in a complete raceway system?
Don
 
Don, there is no need for an exception until the day there is a definite number given to the length of "sections of cable" and then we would have to know why a complete raceway system is not considered protection for the cable.

After that I could see a need for an exception.

Unless there is some specific wording prohibiting the cable from being installed in the article it is allowed.

400.8(6) would be a pretty good example of specifically prohibiting a cable from being installed in a raceway.

Roger
 
jxofaltrds said:
If you use conduit how are you securing it? 4 1/2'? At boxes? etc.
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When you fish a cable into any void how are you securing it?

Here is the exception that Don was asking for.

334.30(B) Unsupported Cables. Nonmetallic-sheathed cable shall be permitted to be unsupported where the cable:
(1) Is fished between access points, where concealed in finished buildings or finished panels for prefabricated buildings and supporting is impracticable
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Be sure to read this section correctly.

334.30(B) Unsupported Cables. Nonmetallic-sheathed cable shall be permitted to be unsupported where the cable:

(1) Is fished between access points, [STOP] where concealed in finished buildings [Stop] or finished panels for prefabricated buildings and supporting is impracticable
 
Bob, even though I agree with your reasoning it still is not necessary.

Looking at 334.30 before we get to the subsections.

334.30 Securing and Supporting
Nonmetallic-sheathed cable shall be supported and secured by staples, cable ties, straps, hangers, or similar fittings designed and installed so as not to damage the cable, at intervals not exceeding 1.4 m (4 1/ 2 ft) and within 300 mm (12 in.) of every outlet box, junction box, cabinet, or fitting. Flat cables shall not be stapled on edge.
Sections of cable protected from physical damage by raceway shall not be required to be secured within the raceway.
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Until we know what the maximum length of a "section of cable" installed in a raceway is, the last sentence above covers all NM installations in a raceway unless the raceway offers no protection from physical damage.

Roger
 
roger said:
Until we know what the maximum length of a "section of cable" installed in a raceway is, the last sentence above covers all NM installations in a raceway unless the raceway offers no protection from physical damage.
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I agree.


I was just being a bit of a wise guy. :D
 
Roger,
There is nothing in the section that you cited that says you don't need to secure the NM within 12" of the box. In my opinion a "section" is not at complete raceway system. I'm not saying that there is a set length of a "section" just that a section does not terminate at enclosures at both ends.
Don
 
Boy Don, you are really grasping for straws here aren't you. Do you have a vested interest in this being disallowed?

The word "section" is not pertaining to the raceway as it is worded, it is referring to the cable.

Sections of cable protected from physical damage by raceway shall not be required to be secured within the raceway.
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The definition of raceway is;

Raceway. An enclosed channel of metal or nonmetallic materials designed expressly for holding wires, cables, or busbars, with additional functions as permitted in this Code. Raceways include, but are not limited to, rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible conduit, flexible metallic tubing, flexible metal conduit, electrical nonmetallic tubing, electrical metallic tubing, underfloor raceways, cellular concrete floor raceways, cellular metal floor raceways, surface raceways, wireways, and busways.
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please explain where a raceway can be a "sleeve" or a "chase". What do you interpret "enclosed" to mean?

Unless you can quote something specific, there is nothing prohibiting the installation, read Bob's post.

If I see the section changed to the following wording in 2008 I will concede you are right.

334.30 Securing and Supporting
Nonmetallic-sheathed cable shall be supported and secured by staples, cable ties, straps, hangers, or similar fittings designed and installed so as not to damage the cable, at intervals not exceeding 1.4 m (4 1/ 2 ft) and within 300 mm (12 in.) of every outlet box, junction box, cabinet, or fitting. Flat cables shall not be stapled on edge.
Sections of cable protected from physical damage by raceway shall not be required to be secured within the raceway.
For application of this section it will be up to Don and his opinion as to whether the last sentence will apply. ;)

Roger
 
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