# Perpendicular to air flow.......



## Roger123

300.22(B) does not allow NM cable in a plenum used for environmental air. It must be sleeved.


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## Nosparxsse

Roger123 said:


> 300.22(B) does not allow NM cable in a plenum used for environmental air. It must be sleeved.



READ FURTHER SIR>>>>>>


300.22
Exception:This section shall not apply to the joist or stud spaces of dwelling units where............:thumbsup:


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## Roger123

Are you quoting 300.22(C)?


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## Nosparxsse

Roger123 said:


> Are you quoting 300.22(C)?



yes. it says this section. (i hate this stupid book...)


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## Roger123

I do not believe that section applies to your OP.


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## Nosparxsse

so you r saying............exception applies to "C" only not 300.22 in its entirety??:blink:


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## Roger123

Yes, the exception in 300.22(C) applies to that section only, 300.22(C). What it is meaning that "Other space used for environmental air" does not apply to joist or stud spaces of dwelling units. Read the FPN, it gives an example of what "other space used for environmental air."


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## Roger123

The reason for not allowing NM in a plemuns is in case the insulations melts or burns, it emit harmful fumes. Why they want it sleeved.


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## Nosparxsse

Roger123 said:


> Yes, the exception in 300.22(C) applies to that section only, 300.22(C). What it is meaning that "Other space used for environmental air" does not apply to joist or stud spaces of dwelling units. Read the FPN, it gives an example of what "other space used for environmental air."




So, the previous inspector interpreted it a different way I guess............ Because there are hundreds of homes done this way in our area................


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## Roger123

Well, I hope it works out for you one way or the another, good luck!


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## gilbequick

Yeah if there's a fire in that bay there's nothing stopping it. It's got plenty of fresh fuel to keep it going. That just doesn't seem safe any way you look at it. I'd run it somewhere else if at all possible, and if not just sleeve it in some pvc.


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## randomkiller

gilbequick said:


> Yeah if there's a fire in that bay there's nothing stopping it. It's got plenty of fresh fuel to keep it going. That just doesn't seem safe any way you look at it. I'd run it somewhere else if at all possible, and if not just sleeve it in some pvc.


 
You can't sleeve it in PVC, that is one point of the problem, it has to be in a non combustable sleeve.


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## raider1

I diagree with you Roger, A stud space in a dwelling unit that is used as for return air is not a plenum, but is "Other spaces used for enviromental air". So as long as the NM cable is running perpendicular to the long dimension of such space you can pass through the cold air return.

Chris


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## Bkessler

Raider1 is right I have done this 100's of times. Just fire stop the holes. YOu can put a plastic box in there to if you just bring the wires in right above or below the box from an adjacent space and find a little piece of sheet metal 3 1/2" wide by about 16" long and just wrap it over the box and wires. I usually cram a little insulation in there as well around the box. I have never been red tagged for this and it saves time cause you just wire as normal just bring your wires in the space next to the box.


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## Nosparxsse

Still debating this................. Gonna have a long dicusision with Mr. Inspector. (AHJ)........I will keep y'all posted......:thumbsup:


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## oldnslow

2005 HANDBOOK TIME.........

"The exemption to 300.22c permits cable to pass through joist or stud spaces of a dwelling unit, as illustrated in Exhibit 300.21. The joist space is covered with sheet metal and used as a cold air return for a forced warm air central heating system. Equipment such as junction boxes or device enclosures is not permitted in this location."

To place a plastic box in a return air stud space I make a u out of 3 pieces of 2x4 slightly wider than the box. This nailed in place around the box removes it from the plenum space.

oldnslow


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## Roger123

raider1 said:


> I diagree with you Roger, A stud space in a dwelling unit that is used as for return air is not a plenum, but is "Other spaces used for enviromental air". So as long as the NM cable is running perpendicular to the long dimension of such space you can pass through the cold air return.
> 
> Chris


Chris,

Maybe you may want to rethink your position. Even the NECH states the following with reference to 300.22: the rules in parts (B) & (C) exclude from use in *all air-handling space* any wiring that is not metal-jacketed or metal-enclosed, to minimize the creation of toxic fumes due to burning plastic under fire conditions."

Also, 300.22(C) FPN gives an example of "Other space used for environmental air," basically hung ceilings.

300.22(C) Exception applies to this sub-section (C) which is *not* "Other space used for environmental air. I believe the intent of the code here is to state that "joist or stud spaces of dwelling unit" *are not* "Other space." So therefore "joist or stud spaces are "ducts or plenums."


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## JohnJ0906

Roger123 said:


> Chris,
> 
> Maybe you may want to rethink your position. Even the NECH states the following with reference to 300.22: the rules in parts (B) & (C) exclude from use in *all air-handling space* any wiring that is not metal-jacketed or metal-enclosed, to minimize the creation of toxic fumes due to burning plastic under fire conditions."


Roger, does not apply. See the exception to 300.22(C).



> Also, 300.22(C) FPN gives an example of "Other space used for environmental air," basically hung ceilings.


That's only one example, not the only space that qualifies.



> 300.22(C) Exception applies to this sub-section (C) which is *not* "Other space used for environmental air. I believe the intent of the code here is to state that "joist or stud spaces of dwelling unit" *are not* "Other space." So therefore "joist or stud spaces are "ducts or plenums."


READ the other parts. Space between studs doesn't fit into them at all.

Although I admit this is not as clear as it could be, the exception (IMO) removes the additional requirements of 300.22(C)(1) and (2)


nosparxsse, if this has been allowed, go directly over his head. Right now. Sounds like he is trying to "mark his territory".


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## randomkiller

JohnJ0906 said:


> Roger, does not apply. See the exception to 300.22(C).
> 
> 
> 
> That's only one example, not the only space that qualifies.
> 
> 
> 
> READ the other parts. Space between studs doesn't fit into them at all.
> 
> Although I admit this is not as clear as it could be, the exception (IMO) removes the additional requirements of 300.22(C)(1) and (2)
> 
> 
> nosparxsse, if this has been allowed, go directly over his head. Right now. Sounds like he is trying to "mark his territory".


When a joist space is enclosed with sheetmetal or sheetrock it is the same as it was a duct with the specific job of conveying air from one space to another, unlike a dropped ceiling space that is not acutually sealed like a duct. I have been over this numerous times with EI in various locations, dwelling units and officies, they always say the same things.


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## JohnJ0906

The NECHB commentary (yes I know not enforceable) specifically allows this.

Done it for years, and never been even commented on by an inspector.


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## randomkiller

JohnJ0906 said:


> The NECHB commentary (yes I know not enforceable) specifically allows this.
> 
> Done it for years, and never been even commented on by an inspector.


Then you've just lucked out. I see things other guys from my company have done that I know are code viloations and the EI's just seem to miss most of them. They seem to get hung up on certain things in some jobs and miss other blatent items.


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## JohnJ0906

randomkiller said:


> Then you've just lucked out. I see things other guys from my company have done that I know are code viloations and the EI's just seem to miss most of them. They seem to get hung up on certain things in some jobs and miss other blatent items.


This is not a code violation. Your EIs are wrong.


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## oldnslow

The code exception states *in dwelling units. *The clarification and added picture in the handbook clearly allow the running of cable perpendicular through the space.


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## Roger123

JohnJ0906 said:


> The NECHB commentary (yes I know not enforceable) specifically allows this.


John,
1. Unless we are reading from two different NECH, the one I'm reading out of disagrees with the above quote. Once again, quote: "the rules in parts (B) and (C) [330.22] exclude from use in *all air-handling spaces* any wiring that *is not metal-jacketed or metal-enclosed*, to minimize the creation of toxic fumes due to burning plastic under fire condition." NM Cable has plastic insulation. Source:NECH, 25Th edition, Brian J. McPartland & Joseph F. McPartland, page 555, last paragraph.

2. I really don't think that anyone can make an argument that in the OP this is not an *air-handling space*.

3. Now, for the most important part and regardless of what the Code demands, why would anyone *knowingly* want to create a *real possibility* of circulating toxic fumes? Shouldn't we be focused on this and not what the Code demands?


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## raider1

> The exception to 300.22(C) permits cable to pass through joist or stud spaces of a dwelling unit, as illustrated in Exhibit 300.21. The joist space is covered with sheet metal and used as a cold-air return for a forced warm-air central heating system. Equipment such as junction boxes or device enclosures is not permitted in this location.​




If you can't run NM cable through a joist or stud space perpedicular to the long dimension of that space why does the exception to 300.22(C) exist?

Please take a look at Exhibit 300.21 in the NECH. This specifically shows a cable passing through a stud space used as a cold air return in a dwelling unit according to the exception to 300.22(C).

Chris​


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## Roger123

raider1 said:


> If you can't run NM cable through a joist or stud space perpedicular to the long dimension of that space why does the exception to 300.22(C) exist?
> 
> Chris[/left]
> [/font]


Chirs,

I believe that the exception exist in 300.22(C) so that joists or studs of dwelling units do not get included in this section with "Other Spaces." So, the question arises where do joists or studs apply? 300.22 (A) & (B). There is no exceptions in either of these sub-section, (A) or (B). I don't think that an argument can be made that a joists or studs can fall under "Other Spaces." The FPN states a good example of what "Other Spaces" are, hung ceilings.

Also, is support of my position is 300.21.


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## Roger123

raider1 said:


> Please take a look at Exhibit 300.21 in the NECH. This specifically shows a cable passing through a stud space used as a cold air return in a dwelling unit according to the exception to 300.22(C).
> 
> Chris[/left]
> [/font]


Chris,
Sorry my 25Th. Edition does not show your Exhibit. It states no NM in any air-handling spaces to minimize the creation of toxic fumes due to burning plastic.


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## raider1

> I don't think that an argument can be made that a joists or studs can fall under "Other Spaces." The FPN states a good example of what "Other Spaces" are, hung ceilings.
> 
> Also, is support of my position is 300.21.


The fineprint note just shows one example of other spaces and is not limited to just ceiling spaces.

There is no reason to have the exception in 300.22(C) if joist spaces in dwelling units weren't classified as "Other spaces for enviromental air"

I will try to post an image of the section in the handbook that I referenced.

Chris


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## randomkiller

raider1 said:


> The fineprint note just shows one example of other spaces and is not limited to just ceiling spaces.
> 
> There is no reason to have the exception in 300.22(C) if joist spaces in dwelling units weren't classified as "Other spaces for enviromental air"
> 
> I will try to post an image of the section in the handbook that I referenced.
> 
> Chris


 
Once a joist space is enclosed to convey air it is now a return duct just as if it was made from sheetmetal in every other aspect of NFPA codes, so I don't think it would be considered "other space".


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## Roger123

Chris,
Is your position that joist or studs are not Ducts or Plenums used for environmental Air?


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## Roger123

Chris,

One more question. Setting everything aside, do you believe that exposed NM without a metallic jacket installed in any air handling space creates a possibility of circulating toxic fumes?


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## brian john

No study completed here just my opinion. If a fire has progressed to the point that plenum is now a chimney the fire has gone beyond any point where NM contamination is your minor or major worry.


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## randomkiller

brian john said:


> No study completed here just my opinion. If a fire has progressed to the point that plenum is now a chimney the fire has gone beyond any point where NM contamination is your minor or major worry.


Maybe the wires going through the bay space are overheating from a loose wire connection and the heat is making the jacket give off fumes into the moving air stream and delivering them throughout the living space via the airflow as the family is sleeping. Wouldn't be the first time.


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## JohnJ0906

I think this is one of the places that the changes to the NEC over the years has made something more unclear. IMO, this (unchanged) exception was placed in such a way as to be much clearer in past editions.


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## JohnJ0906

Nosparxsse, check with the head inspector. Find out if there has been a change in interpretation.


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## brian john

I would not run ANY wiring through a fresh air return in a house (I know I know drop ceiling and underfloor in commercial establishments) talking houses.

But that same overheated wire would cause a fire if not in a chase.......


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## randomkiller

brian john said:


> I would not run ANY wiring through a fresh air return in a house (I know I know drop ceiling and underfloor in commercial establishments) talking houses.
> 
> But that same overheated wire would cause a fire if not in a chase.......


Well you really wouldn't run anything but plenum rated wiring in a drop ceiling used as a plenum in a commercial use either. All we do is commercial-industrial-municipal and I can't remember the last time we have used any NM-NMB on any job we have done. For that matter, other than a few one story medical officies I rarely see wood framing.


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## Roger123

JohnJ0906 said:


> I think this is one of the places that the changes to the NEC over the years has made something more unclear. IMO, this (unchanged) exception was placed in such a way as to be much clearer in past editions.


John,

Here's something we do agree on!


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## raider1

Roger123 said:


> Chris,
> Is your position that joist or studs are not Ducts or Plenums used for environmental Air?


My position is that joist spaces in studs in a *dwelling unit* are NOT ducts and plenums but in fact "Other spaces used for enviromental air".




> One more question. Setting everything aside, do you believe that exposed NM without a metallic jacket installed in any air handling space creates a possibility of circulating toxic fumes?


No more so then PEX water lines, ABS and PVC drain lines ect... These items are allowed to be installed in a joist space used as a cold air return in a dwelling unit.

Again here is what the NECH has to say about the exception to 300.22(C)



> The exception to 300.22(C) permits cable to pass through joist or stud spaces of a dwelling unit, as illustrated in Exhibit 300.21. The joist space is covered with sheet metal and used as a cold-air return for a forced warm-air central heating system. Equipment such as junction boxes or device enclosures is not permitted in this location.


I know that the handbook comentary is not enforceable as code but the explanation helps the user to understand that the code permits NM cable to be installed through joist or stud spaces of a dwelling unit where the space is covered with sheet metal and used as a cold air return.

Chris​


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## JohnJ0906

I was reading this section today at work, and in (B) I noticed the words "ducts or plenums specifically fabricated to transport environmental air"

I can't see any way that a stud space can fall under this.



randomkiller said:


> Once a joist space is enclosed to convey air it is now a return duct just as if it was made from sheetmetal in every other aspect of NFPA codes, so I don't think it would be considered "other space".


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## randomkiller

raider1 said:


> My position is that joist spaces in studs in a *dwelling unit* are NOT ducts and plenums but in fact "Other spaces used for enviromental air".
> 
> 
> 
> You can call them "chickens" if you like but if they are connected to an airhandler or furnace they are ducts, no matter what else happens in the world, ask any Fire or Electrical Inspector. The "other spaces" phrase I think you will find refers to areas that act as static air collection points, not directly tied into a return air system.


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## randomkiller

JohnJ0906 said:


> I was reading this section today at work, and in (B) I noticed the words "ducts or plenums specifically fabricated to transport environmental air"
> 
> I can't see any way that a stud space can fall under this.


If you have a grill on one end and a duct to the intake of a piece of heating equipment on the other end, the conveyance in between is a return duct. Return ducts can legally be constructed of fiberglass, metal, plastic, or sheetrock.


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## raider1

randomkiller said:


> raider1 said:
> 
> 
> 
> My position is that joist spaces in studs in a *dwelling unit* are NOT ducts and plenums but in fact "Other spaces used for enviromental air".
> 
> 
> 
> You can call them "chickens" if you like but if they are connected to an airhandler or furnace they are ducts, no matter what else happens in the world, ask any Fire or Electrical Inspector. The "other spaces" phrase I think you will find refers to areas that act as static air collection points, not directly tied into a return air system.
> 
> 
> 
> So the space above a drop ceiling is a duct? According to your definition it would be. I am an electrical inspector and I don't define the joist space in a dwelling unit used for return air as a "Duct or Plenum" I define them as "Other spaces used for enviromental air" and therefore they are subject to 300.22(C) and the exception to that section.
> 
> Did you read the NECH quote that I posted?
> 
> Chris
Click to expand...


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## Roger123

raider1 said:


> randomkiller said:
> 
> 
> 
> So the space above a drop ceiling is a duct? According to your definition it would be. I am an electrical inspector and I don't define the joist space in a dwelling unit used for return air as a "Duct or Plenum" I define them as "Other spaces used for environmental air" and therefore they are subject to 300.22(C) and the exception to that section.
> 
> Did you read the NECH quote that I posted?
> 
> Chris
> 
> 
> 
> Chris,
> 
> Just for the sake of discussion I will respond to your question, because I know how I will run NM when it comes to this situation.
> 
> First, Your NECH quote carries no weight with me, because I have one that reads opposite from the one your are reading. Please list the edition and authors. I have listed mine.
> 
> Second, the space above a drop ceiling is not a duct or plenum *as used in 300.22(B)* it is "Other space used for environmental air", 300.22(C). The FPN is very clear on this definition.
> 
> Third, My belief of "Specifically fabricated," is *also* a stud designed for air-handling purposes. Studs are commonly used for this purpose in dwellings.
> 
> Forth, I have never once seen plumbers use any stud that was designed for air-handling purposes like you posted using plastic piping. Just because I have never observed this doesn't mean anything so I will check with a master plumber tomorrow at work.
> 
> Fifth, I see you may have overlooked the question directed at you with reference to what practice you install in this situation. Was that deliberate or did I put you in a bad situation? Feel free not to answer, my position is I am here to learn only. Thanks for a good debate.
Click to expand...


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## randomkiller

raider1 said:


> randomkiller said:
> 
> 
> 
> So the space above a drop ceiling is a duct? According to your definition it would be. I am an electrical inspector and I don't define the joist space in a dwelling unit used for return air as a "Duct or Plenum" I define them as "Other spaces used for enviromental air" and therefore they are subject to 300.22(C) and the exception to that section.
> 
> Did you read the NECH quote that I posted?
> 
> Chris
> 
> 
> 
> I never said the space above a drop ceiling was a duct, I never mentioned that at all. That would be a plenum (a box used to contain HVAC air). To me a duct has a readable air velocity, I have never seen a sensible reading taken from a non sealed space above a ceiling but, you sure can get a reading from a 3.5'' x 14'' joist space with a velometer.
> 
> I don't do nor have I ever done residential work as a regular part of my job. But, if the space above a drop ceiling when in a commercial space is enclosed by insulation and or sheetrock and ceiling tiles and connected to an airhandling piece of equipment constitutes a plenum that requires me to use plenum jacketed wiring, then why would it not be a plenum in a residence where people dwell (sleep)?
> 
> So tell us in your own words inspector, what is a return duct? How is it constructed? Does it have to be metal? Prefabed? Tell us oh wise one.
> 
> Just because you maybe employed in a job/career doesn't mean you are any good at it.
Click to expand...


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## Roger123

randomkiller said:


> raider1 said:
> 
> 
> 
> I never said the space above a drop ceiling was a duct, I never mentioned that at all. That would be a plenum (a box used to contain HVAC air). To me a duct has a readable air velocity, I have never seen a sensible reading taken from a non sealed space above a ceiling but, you sure can get a reading from a 3.5'' x 14'' joist space with a velometer.
> 
> I don't do nor have I ever done residential work as a regular part of my job. But, if the space above a drop ceiling when in a commercial space is enclosed by insulation and or sheetrock and ceiling tiles and connected to an air handling piece of equipment constitutes a plenum that requires me to use plenum jacketed wiring, then why would it not be a plenum in a residence where people dwell (sleep)?
> 
> So tell us in your own words inspector, what is a return duct? How is it constructed? Does it have to be metal? Prefabbed? Tell us oh wise one.
> 
> Just because you maybe employed in a job/career doesn't mean you are any good at it.
> 
> 
> 
> Wow, now I know why your screen name ends with Killer!
> 
> I agree with you on this subject, but I have read many of Chris' posts and I find him very informative and intelligent and he has help, with others, to educated me in the understanding of the NEC. He is a good guy and has at many times disagreed with EI's.
> 
> Glad to read that you have much experience in commercial work. I have little experience in commercial work and it's good to know where I can find help. Thanks
Click to expand...


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## raider1

I will not respond to personal insults.

I have not made any personal attacks and don't intend to do so.



> I never said the space above a drop ceiling was a duct, I never mentioned that at all. That would be a plenum (a box used to contain HVAC air).


The space above a drop ceiling is "Other spaces used for enviromental air" and subject to 300.22(C) as referenced in the FPN in 300.22(C) not a "Plenum" as talked about in 300.22(B).



> First, Your NECH quote carries no weight with me, because I have one that reads opposite from the one your are reading. Please list the edition and authors. I have listed mine.


Roger,

I have quoted from the,*
National Electrical Code​*_​_​​​® Handbook
Tenth Edition​
*Mark W. Earley, P.E.​*Editor-in-Chief​*Jeffrey S. Sargent​*Senior Editor​*Joseph V. Sheehan, P.E.​*Editor​*John M. Caloggero​*Editor​With the complete text of the 2005 edition of the​​_National Electrical Code®_

I am not aware of a 25th edition of the National Electrical Code Handbook. I checked with a few other people that I know that have the 2005 handbook and they all have the Tenth Edition.




> Second, the space above a drop ceiling is not a duct or plenum *as used in 300.22(B)* it is "Other space used for environmental air", 300.22(C). The FPN is very clear on this definition.


​ 
I agree, I don't believe that I ever stated that the space above a suspended ceiling is a plenum or duct, I was just trying to make a point.




> Third, My belief of "Specifically fabricated," is *also* a stud designed for air-handling purposes. Studs are commonly used for this purpose in dwellings.


 
A stud space in a dwelling unit is IMO not specifically fabricated as a duct but instead is a space that is built that serves two purposes, First as a structural element in a floor or wall system, and the second funtion is that of "Other spaces used for enviromental air" as defined in 300.22(C).



> Forth, I have never once seen plumbers use any stud that was designed for air-handling purposes like you posted using plastic piping. Just because I have never observed this doesn't mean anything so I will check with a master plumber tomorrow at work.


It is very common for plumbers in my area to pass PEX or ABS pipes perpendicular through a stud space or floor joist space used for enviromental air. There is no code that I am aware of that prohibits plastic plumbing pipes from passing through a stud space used for enviromental air.



> Fifth, I see you may have overlooked the question directed at you with reference to what practice you install in this situation. Was that deliberate or did I put you in a bad situation? Feel free not to answer, my position is I am here to learn only. Thanks for a good debate.


I haven't intentionally avoided any question, were you asking if I would run NM cable perpendicular through a stud space used for enviromental air in a dwelling unit? The answer is yes, the exception to 300.22(C) specifically allows NM cable to be run perpedicular through joist or stud spaces of a dwelling unit used for return air.

Roger, I too feel this has been a good debate, and apperciate your keeping this professional.

​Chris


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## randomkiller

raider1 said:


> I will not respond to personal insults.
> 
> It's only an insult if you take it as one. That was in responce to "I am an electrical inspector", that pulls no weight in a debate here to me.
> 
> But you did avoid my question. What in your opinion makes a ceiling space in a dwelling unit a plenum. I read your answer to a joist space not being a duct and believe your wrong. Can you explain why it would be different in commercial than it is in residential? Your answer could save my company thousands a month on plenum rated wire.


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## Roger123

Chris,

I'm kind of drawing this discussion to a close here. We obviously have two different edition of NECH. Editions different and authors also, and also two different opinions! :001_huh: 

I asked our master plumber at work today with reference to plastic piping running to stud spaces. His real quick response was noway, not allowed. I also ask for a code section. He did not have his code book, but said he will provide one soon.

Guess we will just have to agree to disagree!


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## Roger123

Nosparxsse said:


> Ok, we have a new inspector in our area, and I am having a hissy.
> Situation:
> been doin this for 10 years...............and the exception is plainly read in the code in wiring methods.....now here goes.
> 
> Have a $400,000 home I am wiring. When inspector shows up he says that all the wires in the walls that are run horizontally through the studs cannot pass through a cold air return.  News to me!!!! He said they have to be in pipe, or be plenum rated...........(romex...14/2, and 12/3) plenum rated................:blink:
> our local codes do not state such nonsense, and this is ridiculous.
> 
> Anyone??


Nosparxsse,

Guess this subject was tossed around enough, any recent decision by the inspector?


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## raider1

> It's only an insult if you take it as one.


How is "Just because you maybe employed in a job/career doesn't mean you are any good at it." not meant to be taken as an insult?



> That was in responce to "I am an electrical inspector", that pulls no weight in a debate here to me.


The reason that I pointed out that I am an Electrical inspector is in response to this comment:



> You can call them "chickens" if you like but if they are connected to an airhandler or furnace they are ducts, no matter what else happens in the world, ask any Fire or Electrical Inspector.


My point was that as an electrical inspector the NEC does not define joist and stud spaces in dwelling units used as return air spaces as ducts or plenums per 300.22(B) but instead defines them as "Other spaces used for enviromental air" per 300.22(C).



> But you did avoid my question. What in your opinion makes a ceiling space in a dwelling unit a plenum. I read your answer to a joist space not being a duct and believe your wrong.


In my opinion the exception to 300.22(C) specifically deals with joists and stud spaces in dwelling units used as return air spaces. These spaces are "Other spaces used for enviromental air". If the NEC didn't define these spaces as "Other spaces used for enviromental air" then there would be no reason for the exception. I believe that the NEC as determined that nonmetallic cables within dwelling units that pass perpendicular through stud spaces used to convey return air don't pose a significant hazard and therefore they included the exception to 300.22(C).



> We obviously have two different edition of NECH. Editions different and authors also, and also two different opinions! :001_huh:


My NECH is published by NFPA as the 2005 National Electrcial Code Handbook. 



> Guess we will just have to agree to disagree!


Yes, we will have to agree to disagree. 

Chris


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## Roger123

raider1 said:


> Yes, we will have to agree to disagree.
> 
> Chris


Cool, now we finally agree!!:thumbsup:


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## Nosparxsse

*no recent news from our inspector......but*

just for grins............. 300.22 exception

I want to know where in the code book it tells if the exception applies to the entire article 300.22 or just part C.(it says "this section" at the end of section 300.22) I am trying to learn here.... I learn new things every day. I am gonna stand my ground on this one.


Like someone else said before.....we will have to agree to disagree on this one.:thumbup:


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## Mountain Electrician

The exception to 300.22(C) permits cable to pass through joist or stud spaces of a dwelling unit, as illustrated in Exhibit 300.19. The joist space is covered with sheet metal and used as a cold-air return for a forced warm-air central heating system. Equipment such as junction boxes or device enclosures is not permitted in this location. 







Exhibit 300.19 A cable passing through joist spaces of a dwelling unit, as permitted by 300.22(C), Exception.


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## Nosparxsse

Mountain Electrician said:


> The exception to 300.22(C) permits cable to pass through joist or stud spaces of a dwelling unit, as illustrated in Exhibit 300.19. ?????????
> 
> 
> 
> 
> So is this in the handbook???????
> 
> So does this mean I am right.:001_huh:
> 
> The exception must mean the whole section of 300.22 then.


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## Mountain Electrician

Nosparxsse said:


> Mountain Electrician said:
> 
> 
> 
> The exception to 300.22(C) permits cable to pass through joist or stud spaces of a dwelling unit, as illustrated in Exhibit 300.19. ?????????
> 
> 
> 
> 
> So is this in the handbook???????
> 
> So does this mean I am right.:001_huh:
> 
> The exception must mean the whole section of 300.22 then.
> 
> 
> 
> This is from the 2002 Handbook, and with no change to this exception in '05 you are right. A picture is worth a thousand words.
Click to expand...


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## raider1

Nosparxsse said:


> Mountain Electrician said:
> 
> 
> 
> The exception to 300.22(C) permits cable to pass through joist or stud spaces of a dwelling unit, as illustrated in Exhibit 300.19. ?????????
> 
> 
> 
> 
> So is this in the handbook???????
> 
> So does this mean I am right.:001_huh:
> 
> The exception must mean the whole section of 300.22 then.
> 
> 
> 
> The exception is just for 300.22(C), but as I have stated before the joist space in a dwelling unit used for return air is classified as Other spaces and is subject to300.22(C) and not 300.22(B).
> 
> 
> 
> 
> 
> This is from the 2002 Handbook, and with no change to this exception in '05 you are right. A picture is worth a thousand words.
> 
> Click to expand...
> 
> Thanks Mountain Electric, for posting that picture that is the one I wanted to post earlier but couldn't figure out how to post it. It is the same picture that is in the 2005 NEC Handbook.
> 
> Your right a picture is worth a thousand words.:thumbsup:
> 
> Chris
Click to expand...


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