Page 2 of 2 FirstFirst 12
Results 66 to 129 of 129

Thread: Bunching Romex

  1. #66
    Lou Romano's Avatar
    Lou Romano Guest

    Default Re: Bunching Romex

    ***Poof***

    Last edited by Lou Romano; 03-09-2012 at 03:55 PM. Reason: Because it was a rant and this is not the place for such things!
    Inspection Referral

  2. #67
    Join Date
    Oct 2011
    Location
    Minneapolis, MN
    Posts
    780

    Default Re: Bunching Romex

    I feel I owe Mr. Watson an apology. In post #63 I only saw what he'd written in #62 after writing most of mine, and because of that did not try at the time to thoroughly understand him but instead latched onto an aspect he hadn't included but that I'm sure he knew about already.

    I found particularly interesting the discussion of the energy of a fault being transformed into electromotive force, something I hadn't considered. Also interesting was the effect of wire length on impedance. After reading his post a few more times I'm better able to absorb it; it's good to begin to understand the ratings of the system as a whole and what affects them (still need to look up a few terms, but I'm almost there!)

    Thank you kindly, Mr. Watson!

    You'll see...considering where I started out, I've learned a lot already in the short time I've been around here; give me a little time and I will become more comfortable with the terminology and better able to appreciate, grasp and discuss the details.

    Do not think of knocking out another person's brains because he differs in opinion from you. It would be as rational to knock yourself on the head because you differ from yourself ten years ago.
    - James Burgh, 1754.

  3. #68
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    601

    Default Re: Bunching Romex

    Part of being an electrician, and electrical inspector, is knowing and understanding that there are exceptions to a lot of things. So, after beating to death what constitutes bundled cable, spacing, and a sink or two, I'll go ahead and stir this into the mix.

    What this says is that if you have a cable that is rated at its' full ampacity (this means that there are portions of the circuit that would be capable of being used at their rated current if not for a portion of the cable being subject to derating) and conditions change so that the ampacity is now reduced on part of the cable, the "change" is ignored for ten feet or less. I'll leave it to your imagination as to how I think this applies to, say, wire in an attic, cables in close proximity whether they touch or not, multiple cables in a conduit exiting the top of a panel that leave the conduit in a non structural ceiling where they aren't bundled, and a few other situations.


    2011 NEC
    310.15 Ampacities for Conductors Rated 0–2000 Volts
    (A) General.

    (2) Selection of Ampacity. Where more than one ampacity
    applies for a given circuit length, the lowest value shall be
    used.
    Exception: Where two different ampacities apply to adjacent
    portions of a circuit, the higher ampacity shall be permitted to
    be used beyond the point of transition, a distance equal to 3.0
    m (10 ft) or 10 percent of the circuit length figured at the
    higher ampacity, whichever is less.



  4. #69
    Join Date
    Oct 2011
    Location
    Minneapolis, MN
    Posts
    780

    Default Re: Bunching Romex

    I'm going to see if I understand this with an example, and you guys can correct me. You have a 60' circuit, mostly with an ampacity rating of 25. Between a switch and a light is a stretch of cable derated to 12.5 because of bundling in the attic, but if that stretch from the switch to the bulb is only 5', it's okay. Is that what's meant by adjacent portions of the circuit? Is it because on short stretches there's little impedance?

    Sheesh, I think if I get a hard copy of the NEC it better be the illustrated one! (Even if code is determined by lawyers and lobbyists, it's definitely written by electricians! )

    Do not think of knocking out another person's brains because he differs in opinion from you. It would be as rational to knock yourself on the head because you differ from yourself ten years ago.
    - James Burgh, 1754.

  5. #70
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Kristi,

    Before one can even consider applying that 10% rule (or 10 feet, whichever is LESS, and usually 10% would be less), one must first make a presumption that whoever screwed up the installation ONLY screwed up the installation in that one area.

    The more reasonable presumption would be that when someone screws up an area, they likely screw up a lot more than one sees.

    Let's take you example of a 60 foot circuit and there is 5 feet which visually requires derating ... unless you can see the entire circuit and its installation, it would not be reasonable to presume that the installer ONLY screwed up that 5 feet you can see, but that they screwed up other areas too.

    To apply that exception to "the lowest value shall be used" one MUST be able to see and document that, indeed, only one some area was screwed up - that ALL other areas were installed correctly. I present the idea that it would be next to impossible, in almost all installations, to document that all other areas were correctly and properly installed and that the exception could be applied.

    Now, Bill, I suppose he has x-ray vision and can see what others cannot see, and therefore Bill may be able to apply exception to all of his installations and inspections.

    Me, I am a mere mortal, I do not have x-ray vision and therefore cannot see through walls, past ceilings, etc., the only way I can see inside the walls is at electrical rough (before the insulation and drywall goes on) and that is when I see all the screwups the installers have made, and I can clearly see that there might be 10% WHICH IS ACTUALLY CORRECT.

    That is, until after they make the corrections I point out, in which case I may have missed, at most, that overall 10%, and that exception nicely covers what I may have missed. And I am okay with that.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  6. #71
    Join Date
    Oct 2011
    Location
    Minneapolis, MN
    Posts
    780

    Default Re: Bunching Romex

    Oh, yes, of course - I wasn't talking about the real world. I just wanted to make sure I understood what the code was saying.

    unless you can see the entire circuit and its installation, it would not be reasonable to presume that the installer ONLY screwed up that 5 feet you can see, but that they screwed up other areas too.

    Ah, but the way the code is stated, it applies to adjacent areas, so you've increased your odds a bit. As I understand it, the stretch that can be excepted must be less than 10% (or 10') regardless of other derated, nonadjacent stretches. So on a 100' circuit you could have 20' of 25 amp, an outlet, 5' of normally-derated-but-excepted, an outlet, another 20' of 25 amp, a switch, 7' of bundled-in-the-attic, a light, then more 25 amp cable and you'd be fine.

    But what do I know?!? Believe me, I'm not trying to argue with anyone, just trying to understand. I don't even know why, I certainly won't use it in my present job. I'm interested in the reasoning behind the rules - and exceptions.

    Do not think of knocking out another person's brains because he differs in opinion from you. It would be as rational to knock yourself on the head because you differ from yourself ten years ago.
    - James Burgh, 1754.

  7. #72
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    601

    Default Re: Bunching Romex

    Super electrician I'm not, and I don't make a habit of wiring using all the "outs" for various rules in the NEC, even the ones I rant on and on about here.

    What I do, however, is take folks to task for what I think is reading too much into what's written, or maybe not reading enough of what is written.

    I, for one, accept that the NEC folks put articles like this in the book because they expect them to be used. Others appear to view them as a impediment to a strict and unwavering view of how things need to be done. Of course, I don't automatically assume the entire job is done wrong, either, and that reasonably competent people are doing the work. I also don't take the view that using these articles on occasion is doing "screwed up work" - it's entirely legal, and it would appear the situation has cropped up more than once or it wouldn't be in the NEC. Of course, I also take the view that the "circuit" is all the cable protected by a circuit breaker, not just the cable from a switch to a light fixture, and that most circuits in a residence probably run close to 100 feet or more of cable. And, if we assume that there are a number of places where this circuit has branches running into a hot attic to a lighting outlet, the rule can be applied multiple times.

    Last edited by Bill Kriegh; 11-20-2011 at 11:21 PM.

  8. #73
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    601

    Default Re: Bunching Romex

    Quote Originally Posted by Kristi Silber View Post
    Oh, yes, of course - I wasn't talking about the real world. I just wanted to make sure I understood what the code was saying.



    Ah, but the way the code is stated, it applies to adjacent areas, so you've increased your odds a bit. As I understand it, the stretch that can be excepted must be less than 10% (or 10') regardless of other derated, nonadjacent stretches. So on a 100' circuit you could have 20' of 25 amp, an outlet, 5' of normally-derated-but-excepted, an outlet, another 20' of 25 amp, a switch, 7' of bundled-in-the-attic, a light, then more 25 amp cable and you'd be fine.

    But what do I know?!? Believe me, I'm not trying to argue with anyone, just trying to understand. I don't even know why, I certainly won't use it in my present job. I'm interested in the reasoning behind the rules - and exceptions.
    By jove! I think you're getting the hang of this - - and it's going to drive Jerry nuts.


  9. #74
    Join Date
    Oct 2011
    Location
    Minneapolis, MN
    Posts
    780

    Default Re: Bunching Romex

    I also take the view that the "circuit" is all the cable protected by a circuit breaker, not just the cable from a switch to a light fixture
    I do too. The "portions" of the circuit are switch-to-fixture or whatever.

    What this says is that if you have a cable that is rated at its' full ampacity (this means that there are portions of the circuit that would be capable of being used at their rated current if not for a portion of the cable being subject to derating) and conditions change so that the ampacity is now reduced on part of the cable, the "change" is ignored for ten feet or less.
    I may be misinterpreting, but it sounds like you are saying, for example, that if you have a stretch of 20' cable on a 100' circuit and 5' of it are bundled in the attic, that stretch of cable does not have to be derated. Is that what you mean?

    What I'm most interested in is the reason for the exception.

    Do not think of knocking out another person's brains because he differs in opinion from you. It would be as rational to knock yourself on the head because you differ from yourself ten years ago.
    - James Burgh, 1754.

  10. #75
    Darrel Hood's Avatar
    Darrel Hood Guest

    Default Re: Bunching Romex

    Jerry,
    Using your logic described in post #70, if one observes problematic bundling in one location, one should assume the same problem exists on all circuits installed by the same electrician. I am unsure by what logic you draw a line. I believe an HI can only identify a problem he sees.


  11. #76
    Roger Frazee's Avatar
    Roger Frazee Guest

    Default Re: Bunching Romex

    2011 NEC
    310.15 Ampacities for Conductors Rated 0–2000 Volts
    (A) General.

    (2) Selection of Ampacity. Where more than one ampacity
    applies for a given circuit length, the lowest value shall be
    used.
    Exception: Where two different ampacities apply to adjacent
    portions of a circuit, the higher ampacity shall be permitted to
    be used beyond the point of transition, a distance equal to 3.0
    m (10 ft) or 10 percent of the circuit length figured at the
    higher ampacity, whichever is less.
    [/quote]



    This is a part of NEC code that I agree leaves you with a lot of imagination to work with ....

    I've never used that code section in residential but my read of the exception is it targets single circuits that only have TWO ampacity considerations. I would also think that you couldn't consider any circuit serving general purpose receptacles. A likely place to use it would be a HVAC circuit to a roof top unit where you would have an adjustment for the new rooftop exposure multiples/rules. So the portion of the circuit on the roof top would have less ampacity than the portion of the circuit not on the rooftop.You could not consider IMO several (more than two) sections of changing ampacity.

    I also do not think this exception gives permission to ignore bundling for NM or derating more than 3 ccc's in conduit not on a rooftop, I think it is speaking to single circuits to a known load.

    I think this way becuase if you consider several circuits in conduit or bundled NM what are the odds that all the circuits are the same length to where you would be allowed to ignore bundling or derating for all of them.

    But I confess I need to review this more as it is a section of code that I am not overly familiar.


  12. #77
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Kristi Silber View Post
    Ah, but the way the code is stated, it applies to adjacent areas, so you've increased your odds a bit.
    Not really as there is another adjacent area just beyond the adjacent area you may be able to see, but not be able to see the next adjacent area.

    As I understand it, the stretch that can be excepted must be less than 10% (or 10') regardless of other derated, nonadjacent stretches. So on a 100' circuit you could have 20' of 25 amp, an outlet, 5' of normally-derated-but-excepted, an outlet, another 20' of 25 amp, a switch, 7' of bundled-in-the-attic, a light, then more 25 amp cable and you'd be fine.
    Except that it does not say that.

    The code is silent on whether or not the 10% (or 10', whichever is smaller) is the maximum for the entire circuit and the code is presuming that the installation was correctly done but that there was some condition which caused this one area to be done this way, and as such is excepted.

    Otherwise one could have, worst case, a 100' circuit with 10' not derated, 10' derated to 10.5 amps, 10' not derated, 10' derated to 10.5 amps, 10' not derated, 10' derated to 10.5 amps, 10' not derated, 10' derated to 10.5 amps, 10' not derated, 10' derated to 10.5 amps,

    I doubt the code is written to allow 50% of the circuit to be derated but excepted out.

    Now I have to read what Bill and Roger wrote as I replied before reading those posts.

    Last edited by Jerry Peck; 11-21-2011 at 04:20 PM. Reason: "Fred"??? where to heck did I get "Fred" from, I meant "Roger"
    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  13. #78
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Roger Frazee View Post
    2011 NEC
    310.15 Ampacities for Conductors Rated 0–2000 Volts
    (A) General.

    (2) Selection of Ampacity. Where more than one ampacity
    applies for a given circuit length, the lowest value shall be
    used.
    Exception: Where two different ampacities apply to adjacent
    portions of a circuit, the higher ampacity shall be permitted to
    be used beyond the point of transition, a distance equal to 3.0
    m (10 ft) or 10 percent of the circuit length figured at the
    higher ampacity, whichever is less.


    This is a part of NEC code that I agree leaves you with a lot of imagination to work with ....

    I've never used that code section in residential but my read of the exception is it targets single circuits that only have TWO ampacity considerations. I would also think that you couldn't consider any circuit serving general purpose receptacles. A likely place to use it would be a HVAC circuit to a roof top unit where you would have an adjustment for the new rooftop exposure multiples/rules. So the portion of the circuit on the roof top would have less ampacity than the portion of the circuit not on the rooftop.You could not consider IMO several (more than two) sections of changing ampacity.

    I also do not think this exception gives permission to ignore bundling for NM or derating more than 3 ccc's in conduit not on a rooftop, I think it is speaking to single circuits to a known load.

    I think this way becuase if you consider several circuits in conduit or bundled NM what are the odds that all the circuits are the same length to where you would be allowed to ignore bundling or derating for all of them.

    But I confess I need to review this more as it is a section of code that I am not overly familiar.[/quote]

    I agree with Roger, I believe this section was written for limited reasons and limited use, and Roger gave some good examples.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  14. #79
    Join Date
    Jul 2008
    Location
    Snowbird (this means I'm retired and migrate between locations), FL/MI
    Posts
    4,086

    Default Re: Bunching Romex

    Quote Originally Posted by Kristi Silber View Post
    ...
    What I'm most interested in is the reason for the exception.
    ...The engineer has tools availble for limiting available fault current, the most common being wire length. The impedance of a wire run means that the longer the run, the lower the availble fault current at the end of the wire...

    There is also heat sink to consider...

    Last edited by H.G. Watson, Sr.; 11-21-2011 at 08:46 PM. Reason: Perhaps Fred Rogers to "Roger"? Its a beautiful day in the Neighborhood... :)

  15. #80
    Join Date
    Oct 2011
    Location
    Minneapolis, MN
    Posts
    780

    Default Re: Bunching Romex

    Quote Originally Posted by H.G. Watson, Sr. View Post
    ...The engineer has tools availble for limiting available fault current, the most common being wire length. The impedance of a wire run means that the longer the run, the lower the availble fault current at the end of the wire...

    There is also heat sink to consider...
    Aha, I guessed right! See, I'm learnin'!

    "Is it because on short stretches there's little impedance?" (post 69)

    Do not think of knocking out another person's brains because he differs in opinion from you. It would be as rational to knock yourself on the head because you differ from yourself ten years ago.
    - James Burgh, 1754.

  16. #81
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    601

    Default Re: Bunching Romex

    Impedance is usually not an issue in residential wiring. Where it does become an issue is the service wires before the main disconnect/over current protection. There are thousands, sometimes tens of thousands of AMPs available and a fault can cause a spectacular show. For examples, enter "arcing" in the You Tube search engine. A few of these (sorry, don't keep a list) Power line arching and line failure - YouTube show the electrical cables "jumping" around and indicate some of the reasons Watson gave for the wire nuts on the service being problematic in the event of a fault.

    Having said that, high resistance connections in residential wiring are a common cause of burned devices and wiring, and a main reason connections are required to be in an enclosure.

    A bit of looking around on various electrical forums will also yield pictures of rigid metal conduit where the sides are blown out when there was an internal fault.


  17. #82
    Roger Frazee's Avatar
    Roger Frazee Guest

    Default Re: Bunching Romex

    Thanks to this forum I finally have to throw my 2008 in the trash from over use and abuse.... the binding has come apart so badly that I can no longer keep the pages in order.

    Going to have to spring for a new one or get the electronic version. I am also going to Sams club and refresh my popcorn supply, though lately I've been reading most threads while swallowing chocolate m&m peanuts.

    Getting back to the subject at hand. It really bugs me that the cmp cannot take just a second to correct the language on bundling or stacking nm cables. The real truth of the matter is bundling is becoming more of a concern and I'm reading in ECM that a new study is going to target this as the "possible" fire cause for several reported but unsolved home fires. I do not think it is debatable that bundling of NM is under the magnifying glass now and I would suspect that section of code will be clarified in the next code cycle or two.

    I also am reasonably certain that the NEC when speaking of bundling of NM means to be tied together in some form or fashion. Lets say I bore a hole through a floor joist and run 5 12/2's thru it then thru the next joist and the next and so on. Obviously while going thru the holes they are going to touch, the only opportunity I have to maintain spacing is between joists. If I pull them tight then most likely they are all going to touch at some point between joists (may one won't but what are the odd's) .. there really is no certainty as to what spacing might result. I've never had this tagged as bundling or not maintaining spacing. Now I have had a few inspectors frown if I start tying those cables together with wire ties between the joists. It looks neat but IMO this is where you get into trouble with the NEC's use of the term bundling. That is a specific term used in the english language and it means to tie together or wrap up... like in a 'bundle'. Stacking is another term used in the NEC and just as undefined as bundling.

    You simply cannot maintain spacing when spanning joists and I don't think you can stack .. you can however bundle to where there is virtually no spacing between cables.

    So In my opinion unless you use some method of tying or wrapping those nm cables for a length of 24 inches they are not bundled.

    Now as for not being able to enforce the definition "bundled" in any other article outside of 520 is hard for me to swallow. I'll bet my lucky star that the cmp meant bundled in article 310 to be the same term as in 520. When the term is used in 520's language it is used in the same context as 310 and clearly is meant to imply the concern on reducing a conductors ampacity ... if bundled.

    So it's my opinion that at this point in time the NEC has not been clear on the intent of the bundling concept and as a result bundling can be anything from several cables very close together (sometimes touching) for 24 inches or to be tied together and touching the continuous 24 inches.

    Now if they had said ' bunched ' things would be crystal clear to this old wireman .....


  18. #83
    Join Date
    Feb 2011
    Location
    Upstate N.Y.
    Posts
    116

    Default Re: Bunching Romex

    Okay, had a little time to review the posts regarding the ad nausea commentary regarding “bundling.”

    I normally am not blessed with the ancillary time necessary to provide such a detailed commentary so after a long holiday weekend, this is what I have come up with.

    First let’s begin with the fact that the term “bundling” does not exist in the NEC.

    Let’s assume that the entire dissertation stems from 310.15(B)(2)(a) which states: “ Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are installed without maintaining spacing for a continuous length longer that 600mm (24”) and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a).”

    All references are from the 2008 NEC which is the currently accepted reference in New York state.

    NM cables are rated for residential branch circuits per 334.8 which refers one to 310.15 where Table 310.16 reflects the 60◦C (140◦F) conductor temperature rating.

    It goes on further to state language very similar to 310.15(B)(2)(a), “Where more than two NM cables containing two or more current carrying conductors are installed without maintaining spacing between the cables, through the same opening in wood framing that is to be fire- or draft stopped using thermal insulation, caulk or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).” Exception shall not apply. The last paragraph that immediately follows states: “Where more than two NM cables containing two or more current carrying conductors are installed in contact with thermal insulation without maintaining spacing between cables, the allowable ampacity of each conductor shall be adjusted in accordance with310.15(B)(2)(a).

    So…..would everyone agree that unless it meets the bolded, italic phrases in the above code references, THERE IS NO ADJUSTMENT FACTOR TO BE APPLIED. Get it? No fire- or draft stopped using thermal insulation, caulk or sealing foam means NO ADJUSTMENT FACTOR. No same opening in wood framing……NO ADJUSTMENT FACTOR!

    The explanation provided in the handbook which is not enforceable as code language does indeed mention “bundling or stacking.” It also states “can” result in overheating.

    There is no definition of “maintaining spacing.”

    If it is so important, then why not define it?

    Therefore, in conclusion, NM cables running parallel, adjacent or any other term describing that which others are referring to as “bundling” are NOT subject to derating unless they travel through the same opening in wood framing AND are fire- or draft stopped using thermal insulation, caulk or sealing foam.

    Additionally, if one were to utilize the calculations posted by others in this forum, which were indeed mathematically correct, except for the interchanging of Fahrenheit and Celsius scales, electrical contractors would be wiring with #6 NM cable to meet the adjustment factors shown.

    (I’ve never encountered “a t ypical 125◦C degree attic.”)

    90◦C is 194◦F

    Most attics I've encountered do not exceed 194F.


    That’s the temperature that would be used during derating of NM cable

    I’ve never seen anyone derate that way.

    I’ve never seen a fire resulting from “bundling” as was originally described by the OP.


    And in my jurisdiction, I AM THE AHJ and I read the code through to the end.


    I don’t stop when I get an answer that supports my point of view.


    I don’t pontificate about information obtained through casual conversation with engineers at manufacturing entities.

    Code councils are apprised of many talented and learned professionals that author such.

    I surmise that if this topic was so important, the ambiguity associated with the term “maintaining spacing” would be identified.


    How does one “maintain spacing” of cable through a hole?


    Is there a product available to facilitate such?

    Anyone who still NEEDS to argue the point, put in a code suggestion for the next council to define “spacing.”

    To all, I apologize for the protracted nature of this post.


    I hope everyone enjoys a safe and Happy Holiday.


  19. #84
    Join Date
    Feb 2008
    Location
    Caledon, Ontario
    Posts
    5,005

    Default Re: Bunching Romex

    Richard,

    Thank you. It makes perfect sense to me.

    Further the research paper indicated succinctly that the problem of bundling does occur where wires are run through holes and foam, caulk are provided there is a increase in temps of the wire.


  20. #85
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Richard D. Fornataro View Post
    There is no definition of “maintaining spacing.”

    If it is so important, then why not define it?
    I started to put in a code change for a definition to define it, but realized that the deadline for code change proposals for the 2014 NEC had just passed (on November 4), so I will put a proposal in for the 2017 NEC.

    And in my jurisdiction, I AM THE AHJ and I read the code through to the end.
    Same in my jurisdiction. And derating has been enforced in South Florida where I used to be by those jurisdictions.

    Derating is in the NEC for a reason, just like AFCIs are in the code for a reason. You may disagree with both of these, some do, but they are both in the code.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  21. #86
    Join Date
    Feb 2011
    Location
    Upstate N.Y.
    Posts
    116

    Default Re: Bunching Romex

    Quote Originally Posted by Jerry Peck View Post
    I started to put in a code change for a definition to define it, but realized that the deadline for code change proposals for the 2014 NEC had just passed (on November 4), so I will put a proposal in for the 2017 NEC.



    Same in my jurisdiction. And derating has been enforced in South Florida where I used to be by those jurisdictions.

    Derating is in the NEC for a reason, just like AFCIs are in the code for a reason. You may disagree with both of these, some do, but they are both in the code.
    Jerry,

    I commend your effort to make defining "spacing" part of the Code. I hope to see it in the next cycle.

    I sincerely hope that you got the part about NOT derating unless the applicable conditions were met for such.

    Oddly enough, I fought that fight on a new hotel where NM was used as allowed and got over-ruled on the derating aspect where the installation involved several NM cables passing through wooden framing members with intumescing fire caulk installed in every hole.

    The trite excuse used as a defense from the other side was that such was an "engineered solution" thereby nullifying my opinion.

    I did want to convey the point however that maintaining spacing and derating is only applicable when in contact with insulation, caulk, etc.

    The customary practice of bundling cables through basement joists, etc. is not a problem and should not be pointed out by HI's.

    Of course, that's probably more prevalent here in the North where we routinely encounter basements in residential construction.


  22. #87
    Join Date
    Jul 2008
    Location
    Snowbird (this means I'm retired and migrate between locations), FL/MI
    Posts
    4,086

    Default Re: Bunching Romex


    2009 IRC

    SECTION E3705 CONDUCTOR SIZING AND OVERCURRENT PROTECTION

    E3705.1 General. Ampacities for conductors shall be determined based in accordance with Table E3705.1 and Sections E3705.2and E3705.3.




    E3705.3 Adjustment factor for conductor proximity. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are stacked or bundled for distances greater than 24 inches (610 mm) without maintaining spacing and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table E3705.3.

    Exceptions:

    1. Adjustment factors shall not apply to conductors in nipples having a length not exceeding 24 inches (610 mm).
    2. Adjustment factors shall not apply to underground conductors entering or leaving an outdoor trench if those conductors have physical protection in the form of rigid metal conduit, intermediate metal conduit, or rigid nonmetallic conduit having a length not exceeding 10 feet (3048 mm) and the number of conductors does not exceed four.

    3. Adjustment factors shall not apply to type AC cable or to type MC cable without an overall outer jacket meeting all of the following conditions:
    3.1. Each cable has not more than three current-carrying conductors.

    3.2. The conductors are 12 AWG copper.

    3.3. Not more than 20 current-carrying conductors are bundled, stacked or supported on bridle rings. A 60 percent adjustment factor shall be applied where the current-carrying conductors in such cables exceed 20 and the cables are stacked or bundled for distances greater than 24 inches (610 mm) without maintaining spacing
    Type NM cable is not used at 90 degrees C but at 60 degrees C. The uncorrected, unadjusted ambient temperature for use of same is 30 degrees C ( 86 degrees F).

    Show me an unconditioned attic that never exceeds 86 degrees F .

    E3904.3 Securing and supporting. Raceways, cable assemblies, boxes, cabinets and fittings shall be securely fastened in place.


    E3904.3.1 Prohibited means of support. Cable wiring methods shall not be used as a means of support for other cables, raceways and nonelectrical equipment.
    The CMPs and the NEC has already addressed. The concept of thermal conductivity was ascribed earlier.

    Quote Originally Posted by 2011 NEC

    Article 310
    Conductors for General Wiring

    310.2 Definitions.

    Thermal Resistivity. As used in this Code, the heat transfer capability through a substance by conduction. It is the reciprocal of thermal conductivity and is designated Rho and expressed in units degrees-C-cm/W.

    310.15 Ampacities for Conductors Rated 0-2000 Volts

    (A) General.
    (3) Temperature Limitation of Conductors. No conductor shall be used in such a manner that its operating temperature exceeds that designated for the type of insulated conductor involved. In no case shall conductors be associated together in such a way, with respect to type of circuit, the wiring method employed, or the number of conductors, that the limiting temperature of any conductor is exceeded.
    Informational Note No. 1: The temperature rating of a conductor (see Table 310.104(A) and Table 310.104(C) is the maximumtemperature, at any location along its length, that the conductor can withstand over a prolonged time period without serious degradation. The allowable ampacity tables, the ampacity tables of Article 310 and the ampacity tables of Informative Annex B, the ambient temperature correction factors in 310.15(B)(2), and the notes to the tables provide guidance for coordinating conductor sizes, types, allowable ampacities, ampacities, ambient temperatures, and number of associated conductors. The principal determinants of operating temperature are as follows:
    (1) Ambient temperature -- ambient temperature may vary along the conductor length as well as from time to time.

    (2) Heat generated internally in the conductor as the result of load current flow, including fundamental and harmonic currents.

    (3) The rate at which generated heat dissipates into the ambient medium. Thermal insulation that covers or surrounds conductors affects the rate of heat dissipation.

    (4) Adjacent load-carrying conductors -- adjacent conductors have the dual effect of raising the ambient temperature and impeding heat dissipation.
    Informational Note No. 2: Refer to 110.14(C) for the temperature limitation of terminations.
    (B) Tables. Ampacities for conductors rated 0 to 2000 volts shall be as specified in the Allowable Ampacity Table 310.15(B)(16) through Table 310.15(B)(19), and Ampacity Table 310.15(B)(20) and Table 310.15(B)(21) as modified by 310.15(B)(1) through (B)(7).


    The temperature correction and adjustment factors shall be permitted to be applied to the ampacity for the temperature rating of the conductor, if the corrected and adjusted ampacity does not exceed the ampacity for the temperature rating of the termination in accordance with the provisiions of 110.14(C).
    (3) Adjustment Factors.
    (a) More than Three Current-Carrying Conductors in a Raceway or Cable. Where the number of current-carring conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are installed without maintaining spacing for a continuous length longer than 600 mm (24 in.) and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(3)(a). Each current-carrying conductor of a paralled set of conductors shall be counted as a current-carrying conductor.
    The communications cable in parallel and zip tied with other systems and cables is bundled. "bundled" is used in both the electrical chapters of the IRC and in the NEC.

    The NM installed through the floor support members is not bundled. There are a host of issues and concerns regarding the OP.

    The subsequent photos and questions raised by others are addressed above and by other posts previously by myself and others.

    Pinching NM under a staple or cable tie, impinging, restricting, compressing the individual conductor(s) insulation , has been a known "issue" for decades and the cause of fires. Similarly known has been the ability of PVC jackets to TRAP heat, nylon and similar, etc.


  23. #88
    Join Date
    Jul 2008
    Location
    Snowbird (this means I'm retired and migrate between locations), FL/MI
    Posts
    4,086

    Default Re: Bunching Romex

    Quote Originally Posted by Richard D. Fornataro View Post
    ...



    I did want to convey the point however that maintaining spacing and derating is only applicable when in contact with insulation, caulk, etc.

    ...
    Untrue.


  24. #89
    Join Date
    Jul 2008
    Location
    Snowbird (this means I'm retired and migrate between locations), FL/MI
    Posts
    4,086

    Default Re: Bunching Romex

    Quote Originally Posted by Richard D. Fornataro View Post
    ...
    ...(I’ve never encountered “a t ypical 125◦C degree attic.”)

    90◦C is 194◦F

    Most attics I've encountered do not exceed 194F.


    That’s the temperature that would be used during derating of NM cable

    I’ve never seen anyone derate that way.

    I’ve never seen a fire resulting from “bundling” as was originally described by the OP.


    And in my jurisdiction, I AM THE AHJ and I read the code through to the end.


    ...

    ambient temperature correction factors apply at/kickin above 86F (30C).

    NM Cable itself limited to use at 60C ampacity.

    Openings in wood blocked/stopped in caulk or foam are NOT the only instances in which adjustments must be considered. Heat from adjacent NM cables (or other cables with a coating impeding heat transfer to free air) in contact for more than 24 continuous inches and not within a raceway are considered.


  25. #90
    Join Date
    Feb 2011
    Location
    Upstate N.Y.
    Posts
    116

    Default Re: Bunching Romex

    Quote Originally Posted by H.G. Watson, Sr. View Post
    Untrue.
    For the love of God.....read 310.15(B)(2)(a) all the way to the end.

    Don't quote code and cut it off where it suits your argument.

    “Where more than two NM cables containing two or more current carrying conductors are installed without maintaining spacing between the cables, through the same opening in wood framing that is to be fire- or draft stopped using thermal insulation, caulk or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).” Exception shall not apply. The last paragraph that immediately follows states: “Where more than two NM cables containing two or more current carrying conductors are installed in contact with thermal insulation without maintaining spacing between cables, the allowable ampacity of each conductor shall be adjusted in accordance with310.15(B)(2)(a).

    Does IRC 2009 differ from NEC 2008?

    What are you not getting out of the above quoted?

    New York State Residential Code does not contain reference to E3705.3 Adjustment factor for conductor proximity.

    It does however state at the beginning of the Part VIII - Electrical Chapter that "This Electrical Part is a compilation of provisions extracted from the 2008 edition of the NEC."

    If NEC and IRC differ....we have no disagreement, however: I am compelled to enforce the requirements of 2008 NEC and have stated such above .

    That which is bolded or enlarged is so that you might actually peruse such.

    You can't possibly argue with a direct quote from the accepted reference manual enforced by the state within which I endeavor.

    As to the temperature rating of NM cable.

    NM cable around here is imprinted with a 90 degree C (194 degree F) temperature rating.

    Despite your protracted display of superfluous electrical code, once again you're quoting from the wrong book.

    NEC 2008

    334.80 Ampacity

    "The ampacity of types NM, NMC and NMS cable shall be determined in accordance with 310.15. The amapacity shall be in accordance with the 60 degree C (140 degree F) conductor temperature rating. The 90 degree C (194 degree F) rating shall be permitted to be used for ampacity derating purposes, provided the final derated capacity does not exceed that for a 60 degree C (140 degree F) rated conductor. The ampacity for types NM, NMC and NMS cable installed in cable tray shall be determined in accordance with 392.11.

    That means that what I previously submitted was correct as written.

    I can perceive that you are obviously an intelligent individual, however; in my short time perusing this forum, I have observed that you prefer to argue for the mere sake of arguing.

    And....when you are wrong, peoples estimation of your contributions become degraded.

    Other than that, I'm sure that you are genuinely concerned with the topics displayed in this forum.

    Your propensity for pontificating in less than correct perceptions of code is deleterious to inexperienced individuals seeking expertise on a given topic.

    Let's try to baffle observers of this forum with brilliance......not BS.

    Last edited by Richard D. Fornataro; 11-30-2011 at 01:38 PM.

  26. #91
    Beverly Cofield's Avatar
    Beverly Cofield Guest

    Default Re: Bunching Romex

    The bundling of cables should be avoided due to the possibility of the cables overheating in this situation. The NEC 310.15(3)(B)(3) addresses this as to installed without maintaining spacing for 2’ or more, derating factors should be used. The number of conductors passing through one hole is not addressed. ROMEX® is a registered trademark of Southwire Company. You will find more information about ROMEX® brand cable at [FONT='Calibri','sans-serif']www.southwire.com/residential/romex.htm[/FONT]

    This communication is for general informational purposes only and is not intended to constitute advice. As all the facts and circumstances in any given situation may not be apparent, this communication is not intended to be, and should not be, relied upon by the reader in making decisions with respect to the issues discussed herein, and the reader assumes the risk if he or she chooses to do so. The reader is encouraged to consult an expert before making any decisions or taking any action concerning the matters in this communication. All warranties, express or implied, including warranties regarding accuracy, adequacy, completeness, legality, reliability, safety or usefulness of any information, ARE DISCLAIMED. Southwire Company is not liable for any damages however caused and on any theory of liability arising in any way out of the information provided or the reader's use of it.

    ROMEX® Cable Fan


  27. #92
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Beverly Cofield View Post
    The bundling of cables should be avoided due to the possibility of the cables overheating in this situation. The NEC 310.15(3)(B)(3) addresses this as to installed without maintaining spacing for 2’ or more, derating factors should be used. The number of conductors passing through one hole is not addressed. ROMEX® is a registered trademark of Southwire Company. You will find more information about ROMEX® brand cable at [FONT='Calibri','sans-serif']Romex ® - Southwire: The Official Home of Romex ® Wire[/font]

    This communication is for general informational purposes only and is not intended to constitute advice. As all the facts and circumstances in any given situation may not be apparent, this communication is not intended to be, and should not be, relied upon by the reader in making decisions with respect to the issues discussed herein, and the reader assumes the risk if he or she chooses to do so. The reader is encouraged to consult an expert before making any decisions or taking any action concerning the matters in this communication. All warranties, express or implied, including warranties regarding accuracy, adequacy, completeness, legality, reliability, safety or usefulness of any information, ARE DISCLAIMED. Southwire Company is not liable for any damages however caused and on any theory of liability arising in any way out of the information provided or the reader's use of it.

    ROMEX® Cable Fan
    Do you work for Southwire?


  28. #93
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Beverly Cofield View Post
    The number of conductors passing through one hole is not addressed.
    Actually it is addressed (under certain conditions) and is not allowed, not without derating.

    - 334.80 Ampacity.
    - - The ampacity of Types NM, NMC, and NMS cable shall be determined in accordance with 310.15. The ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The 90°C (194°F) rating shall be permitted to be used for ampacity derating purposes, provided the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor. The ampacity of Types NM, NMC, and NMS cable installed in cable tray shall be determined in accordance with 392.11.
    - - - Where more than two NM cables containing two or more current-carrying conductors are installed, without maintaining spacing between the cables, through the same opening in wood framing that is to be fire- or draft-stopped using thermal insulation, caulk, or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a) and the provisions of 310.15(A)(2), Exception, shall not apply.
    - - - Where more than two NM cables containing two or more current-carrying conductors are installed in contact with thermal insulation without maintaining spacing between cables, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  29. #94
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Jerry Peck View Post
    Actually it is addressed (under certain conditions) and is not allowed, not without derating.

    - 334.80 Ampacity.
    - - The ampacity of Types NM, NMC, and NMS cable shall be determined in accordance with 310.15. The ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The 90°C (194°F) rating shall be permitted to be used for ampacity derating purposes, provided the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor. The ampacity of Types NM, NMC, and NMS cable installed in cable tray shall be determined in accordance with 392.11.
    - - - Where more than two NM cables containing two or more current-carrying conductors are installed, without maintaining spacing between the cables, through the same opening in wood framing that is to be fire- or draft-stopped using thermal insulation, caulk, or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a) and the provisions of 310.15(A)(2), Exception, shall not apply.
    - - - Where more than two NM cables containing two or more current-carrying conductors are installed in contact with thermal insulation without maintaining spacing between cables, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).
    You wouldn't need to derate for only two cables even if you had 4 CCC's.


  30. #95
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Robert Meier View Post
    You wouldn't need to derate for only two cables even if you had 4 CCC's.
    Did you read the bold part?

    "Where more than two NM cables containing two or more current-carrying conductors"

    2 + 2 = 4

    And the 24" does not apply.

    If that described condition exists through a single top plate of 1-1/2" ... and there are "more than two NM cables containing two or more current-carrying conductors" ... you gotta derate them suckers.

    And don't forget, if those go into the attic, you gotta derate for ambient attic too (I usually recommend derating for ambient first, that let's you know how many current carrying conductors you can have without maintaining spacing - and 4 is too many for normal derating conditions, but here, for this specific conditions, 4 is okay).

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  31. #96
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Jerry Peck View Post
    Did you read the bold part?

    "Where more than two NM cables containing two or more current-carrying conductors"

    2 + 2 = 4

    And the 24" does not apply.

    If that described condition exists through a single top plate of 1-1/2" ... and there are "more than two NM cables containing two or more current-carrying conductors" ... you gotta derate them suckers.

    And don't forget, if those go into the attic, you gotta derate for ambient attic too (I usually recommend derating for ambient first, that let's you know how many current carrying conductors you can have without maintaining spacing - and 4 is too many for normal derating conditions, but here, for this specific conditions, 4 is okay).

    Yes it says more than 2 cables. Meaning two cables, even with 6 CCC's do not require derating when installed in a fire or draft stopped hole.


  32. #97
    Join Date
    Jul 2008
    Location
    Snowbird (this means I'm retired and migrate between locations), FL/MI
    Posts
    4,086

    Default Re: Bunching Romex

    Peck and Fortunato,

    You're NOT PAYING ATTENTION.

    2011 does not read the same as 2008.

    Retorting with selective quotes from a different edition of the NEC is frankly stupid.

    You both lament earlier in this topic thread/discussion about submitting changes for a future edition, yet both fail to recognize when participants reference (frankly in response to your 2008 lamentations) with 2011 code language.

    I identified what I quoted as 2011, (DUH! DIFFERENT TABLE NUMBERS~)

    Peck, responding to Beverly Cofield citing 2011 language with 2008 language was typical for you, oversight, lazy and stupid.

    The entire world is not frozen in time with your outdated 2008, many jurisdictions already use 2011; A Home Inspector should be aware of the CURRENT EDITIONS of the SAFETY CODES regarding BUILDING and PROPERTY MAINTENANCE CODES, etc. Not BACKWARDS IN TIME TO A LESSER 'used to be good enough' standard.


  33. #98
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Robert Meier View Post
    Yes it says more than 2 cables. Meaning two cables, even with 6 CCC's do not require derating when installed in a fire or draft stopped hole.
    Robert,

    You really do need to learn to read better.

    I will repost the code to see if you can read it, to help you in your reading I will break some sentences up for your understanding:
    - 334.80 Ampacity.
    - - The ampacity of Types NM, NMC, and NMS cable shall be determined in accordance with 310.15. The ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The 90°C (194°F) rating shall be permitted to be used for ampacity derating purposes, provided the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor. The ampacity of Types NM, NMC, and NMS cable installed in cable tray shall be determined in accordance with 392.11.
    - - - Where more than two NM cables
    containing two or more
    current-carrying conductors
    are installed,
    without maintaining spacing
    between the cables,
    through the same opening
    in wood framing
    that is to be fire- or draft-stopped using
    thermal insulation,
    caulk,
    or sealing foam,
    the allowable ampacity of each
    conductor
    shall
    be adjusted in accordance with Table 310.15(B)(2)(a) and
    the provisions of 310.15(A)(2), Exception, shall not apply.
    - - - Where more than two NM cables containing two or more current-carrying conductors are installed in contact with thermal insulation without maintaining spacing between cables, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).

    Okay, let us now count the number of conductors in
    more than two NM cables
    containing two or more
    current-carrying conductors


    more than 2 cables (count them: one ... two ... stop counting)
    2 conductors in each cable (could be 3, but the minimum works out well here for your reading improvement)

    Okay, 2 cables with 2 conductors in each is 4 conductors ... and that IS OKAY in this instance.

    Okay, now follow closely here ... MORE THAN 2 cables, means at least 3 cables, and with 2 conductors in each is 6 conductors ... and that IS NOT OKAY in this instance.

    Get it?

    4 conductors in 2 cables with 2 conductors in each cable IS OKAY and derating IS NOT required.
    6 conductors in 3 cables with 2 conductors in each cable IS NOT OKAY and derating IS required.

    Not sure what is so difficult to understand about that ... well, maybe I do understand what may be so difficult - you do not seem to be able to separate the DIFFERENT requirement for derating for more than 3 conductors for more than 24 inches from more than 2 cables with 2 conductors in each cable, foamed/sealed around for as little as 1-1/2".

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  34. #99
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by H.G. Watson, Sr. View Post
    You're NOT PAYING ATTENTION.

    2011 does not read the same as 2008.
    Watson,

    You are the one in your own time zone.

    Most jurisdictions are still using the 2008, so the 2008 is the most common reference. By the way, there is VERY LITTLE change in that code section (334.80)

    Just like most jurisdictions are still using the 2006 ICC codes, thus the most common reference is from the 2006 ICC codes.

    SOME jurisdictions keep up to the minute on code cycle adoptions, alas, it would be nice if all adopted up to the minute code revisions (it would be scary if they did, but nice) - but that is in your dreams ... I'm talking real world here, not in your fantasyland mind.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  35. #100
    Join Date
    Jul 2008
    Location
    Snowbird (this means I'm retired and migrate between locations), FL/MI
    Posts
    4,086

    Default Re: Bunching Romex

    Quote Originally Posted by Richard D. Fornataro View Post

    I did want to convey the point however that maintaining spacing and derating is only applicable when in contact with insulation, caulk, etc.
    R.F.:


    Again, UNTRUE! i.e. your use of the word "ONLY"

    Maintaining spacing and derating IS applicable when in contact continuously for more than 24 inches, was the example given.

    What about the entirety of 310 and 334 can't you retain?



    Peck:

    BAH, HUMBUG. You're tiny corner might be stuck in 2006 IRC and 2008 NEC, the WORLD ACCORDING TO PECK!!??

    CODE ENFORCEMENT IS NOT WHAT THIS SITE IS ABOUT, NEITHER IS "HOME INSPECTION"!!!

    Over the years on this site ("inspectionnews.net") and the now archived ("inspectionnews.com") you've gone on and on about inspecting to the LATEST, SAFEST edition of whatever code as a REFERENCE for HOME INSPECTION relative to SAFETY issues and what to make reference to regarding a home inspection (not necessarily call "deficient").

    The model codes do NOT have a habit of (not intentionally, at least) of falling backwards on the issue of safety, and most certainly not the NEC, which unlike the I-codes are ANSI standard and not so easily politically or singular "interest group" skewed.

    If an HI is going to make a "call" regarding an observed less than safe situation, it matters NOT what code edition JERRY PECK is doing code enforcement with.

    The later editions of the National Electrical Code, NFPA 70 are modified also by the CHANGES in the STANDARDS that the equipment itself is made - and incorporate SAME (harmonize) regarding SAFETY issues and requirements.

    Peck both YOU and R.F. carried on about your efforts to enhance the code and submissions.

    The rest of the country isn't frozen in the 2008, and frankly some jurisdictions are using earlier versions. Few jurisdictions use any edition of the NEC withOUT ammendments.

    You TWO brought up 2011 and 2014.

    Spend a few bucks since you're so inclined to cut and paste wildly. The IDEA that you' had been THINKING about making a submission for 2014 when you can't grasp 2011 (or read for that matter) is frankly, typical, obvious also neither of you keeps up on the White Books, Marking Guides, or changes to the UL Standards for electrical equipment.

    Someone recently posted to this thread today, a pause since Nov last year - you (in your usual manner) had to hit every thread active for the last four hours. You vomited 2008 up to someone who posted 2011 references from the manufacturer of "Romex".

    Last edited by H.G. Watson, Sr.; 03-09-2012 at 09:24 PM.

  36. #101
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Robert Meier View Post
    You wouldn't need to derate for only two cables even if you had 4 CCC's.
    Quote Originally Posted by Robert Meier View Post
    Yes it says more than 2 cables. Meaning two cables, even with 6 CCC's do not require derating when installed in a fire or draft stopped hole.
    Quote Originally Posted by Jerry Peck View Post
    Robert,

    You really do need to learn to read better.


    Okay, let us now count the number of conductors in
    more than two NM cables
    containing two or more
    current-carrying conductors


    more than 2 cables (count them: one ... two ... stop counting)
    2 conductors in each cable (could be 3, but the minimum works out well here for your reading improvement)

    Okay, 2 cables with 2 conductors in each is 4 conductors ... and that IS OKAY in this instance.

    Okay, now follow closely here ... MORE THAN 2 cables, means at least 3 cables, and with 2 conductors in each is 6 conductors ... and that IS NOT OKAY in this instance.

    Get it?

    4 conductors in 2 cables with 2 conductors in each cable IS OKAY and derating IS NOT required.
    6 conductors in 3 cables with 2 conductors in each cable IS NOT OKAY and derating IS required.
    Jerry, you're the one who needs to slow down and read what I wrote. I think that Watson and Fornataro have your panties all up in a bunch and you're not correctly reading my posts.

    I said TWO NM cables, regardless of how many CCC's are in those cables, do not require derating in a sealed hole. I wrote one sentence so I'm unsure why you're so confused. I said TWO cables.

    You can apologize now.


  37. #102
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    601

    Default Re: Bunching Romex

    Cables in fire stopped holes or in contact with thermal insulation---

    I'm pretty much interested in knowing why this gets to be such an issue. Two cables with 2 or more conductors can be, for example, a 14-2 and a 14-2, a 14-2 and a 14-3, a 14-3 and a 14-3, a 14-2 and a 14-2-2, a 14-3 and a 14-2-2, or a 14-2-2 and a 14-2-2. Some enterprising individual could make 14-2-2-2-2-2 and the same rules would apply, as now written.

    Now, with all 14-2s we have 2 circuits. With the other combinations we have either 3 or 4 circuits.

    Other than code wording that says I have to derate more than 2 cables with 2 or more conductors (without maintaining spacing - whatever that is), somebody want to explain the major fire hazard where it's OK to have 4 circuits in 2 multi-conductor cables in the same fire stopped hole not spaced but not to have 4 two wire cables in the same fire stopped hole not spaced? Or, why, somehow, heat dissipation is different between the two situations?

    Or do we assume the CMP is somehow ignorant of 14-3 and 14-2-2 cable and they "meant" for the article to mean 2 circuits (4 current carrying wires)?

    How many read 334.80 and come away thinking you can only run two cables through a fire stopped hole without derating? Not what it says. So the next issue is do we now start seeing an insert for drilled holes to be fire stopped that maintains "spacing". Does that "spacing" get to be 1/6", 1/8"? How about just inserting wood wedges into the hole between cables before caulking or foaming? How many NM-B cables in a 2 inch fire stopped hole with shims installed? Spacing is maintained.

    There's a lot of things in the NEC not to like. One of them is, and continues to be, that without clarification IN WRITING supplied with cable or defined in the NEC, "spacing" continues to mean "doesn't touch" That's just as solid a definition as the one that says that a load that is turned off no less often than every 2 hours 59 minutes and 59 seconds isn't a continuous load, even if after that second it is turned back on again for 2 hours 59 minutes and 59 seconds - but is written as "A load where the maximum current is expected to continue for 3 hours or more. Means the same thing. Practical? Meet code intent? Dunno. Does that 1 second make a real difference?

    Frankly, from my experience, we'd be better served if receptacles and switches were required to be the "back wire" type and beeped incessantly till properly torqued. I've seen many more fires started from improperly installed devices and splices - stuff that, incidentally, almost never gets inspected, than NM-B cables installed as shown in the OPs picture( none, so far) - which, by the way are NOT bundled and maintain "some" spacing over a 2 foot length.

    Occam's eraser: The philosophical principle that even the simplest solution is bound to have something wrong with it.

  38. #103
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Bill Kriegh View Post
    Cables in fire stopped holes or in contact with thermal insulation---

    I'm pretty much interested in knowing why this gets to be such an issue. Two cables with 2 or more conductors can be, for example, a 14-2 and a 14-2, a 14-2 and a 14-3, a 14-3 and a 14-3, a 14-2 and a 14-2-2, a 14-3 and a 14-2-2, or a 14-2-2 and a 14-2-2. Some enterprising individual could make 14-2-2-2-2-2 and the same rules would apply, as now written.

    Now, with all 14-2s we have 2 circuits. With the other combinations we have either 3 or 4 circuits.

    Other than code wording that says I have to derate more than 2 cables with 2 or more conductors (without maintaining spacing - whatever that is), somebody want to explain the major fire hazard where it's OK to have 4 circuits in 2 multi-conductor cables in the same fire stopped hole not spaced but not to have 4 two wire cables in the same fire stopped hole not spaced? Or, why, somehow, heat dissipation is different between the two situations?

    Or do we assume the CMP is somehow ignorant of 14-3 and 14-2-2 cable and they "meant" for the article to mean 2 circuits (4 current carrying wires)?
    In the worst case scenario of off the shelf NM cable, with 2-12/2/2 NM cables in the fire or draft stopped hole you would have 8 CCC's. If you did apply derating to this worst case scernario then you would have a derating factor of 70%. So 30 amps * 70% would give you 21 amps which is still good on a 20 amp OCPD. Whether or not the CMP was cognizant of this fact when they added this to the NEC I don't know.


  39. #104
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Robert Meier View Post
    Jerry, you're the one who needs to slow down and read what I wrote.

    I said TWO NM cables, regardless of how many CCC's are in those cables, do not require derating in a sealed hole.
    Yes sir ... ... that is what you said.

    You can apologize now.
    I do need to slow down and read better ... I do hereby extend my apology to you ... along with my typing hand so you can slap it.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  40. #105
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Robert Meier View Post
    So 30 amps * 70% would give you 21 amps which is still good on a 20 amp OCPD.
    Unless those same conductors ran into the typical ventilated attic, in which case those cables would also need to be derated for ambient temperature.

    start with your 21 amps and derate to 71% for a typical attic, that derated ampacity is now only 14.91 amps ... not good enough for even a 15 amp circuit.

    "Close" to good enough for a 15 amp circuit, but "close" only counts in horse shoes, hand grenades, and atom bombs. (Given in the order of 'how close' "close" needs to be.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  41. #106
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Jerry Peck View Post
    Yes sir ... ... that is what you said.



    I do need to slow down and read better ... I do hereby extend my apology to you ... along with my typing hand so you can slap it.
    No problem Jerry we're all here have a discussion and to share ideas.
    I was confused because almost all of your posts are right on target.


  42. #107
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Bill Kriegh View Post
    I'm pretty much interested in knowing why this gets to be such an issue.
    They were doing testing on this for some time, some of the testing was in the IAEI News a few years back.

    The testing revealed serious overheating at those locations.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  43. #108
    Join Date
    Mar 2009
    Location
    Colorado Front Range
    Posts
    601

    Default Re: Bunching Romex

    It's probably going to take more than a straight face during an explanation to convince me that 4 circuits in 2 14-2-2 cables don't have the same issues (or lack of them) that 4 14-2 cables have in the same fire stopped hole.

    Occam's eraser: The philosophical principle that even the simplest solution is bound to have something wrong with it.

  44. #109
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Bill Kriegh View Post
    It's probably going to take more than a straight face during an explanation to convince me that 4 circuits in 2 14-2-2 cables don't have the same issues (or lack of them) that 4 14-2 cables have in the same fire stopped hole.
    I would not even attempt to try to convince my 6 year-old granddaughter of the above.

    I believe ... yes, I believe ... the intent was in reference to 4 conductors as in 2- 12-2 or 14-2 NM cables. And not necessarily to 12-2-2 NM cables because 12-2-2 cables *already* require derating simply by being 12-2-2 and having 4 current carrying conductors within the same cable. If those cables are *already* required to be derated in 310.15(B)(2):
    - (2) Adjustment Factors.
    - - (a) More Than Three Current-Carrying Conductors in a Raceway or Cable. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are installed without maintaining spacing for a continuous length longer than 600 mm (24 in.) and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a). Each current-carrying conductor of a paralleled set of conductors shall be counted as a current-carrying conductor.
    - - - FPN No. 1: See Annex B, Table B.310.11, for adjustment factors for more than three current-carrying conductors in a raceway or cable with load diversity.
    - - - FPN No. 2: See 366.23(A) for adjustment factors for conductors in sheet metal auxiliary gutters and 376.22(B) for adjustment factors for conductors in metal wireways.
    - - - Exception No. 1: Where conductors of different systems, as provided in 300.3, are installed in a common raceway or cable, the derating factors shown in Table 310.15(B)(2)(a) shall apply only to the number of power and lighting conductors (Articles 210, 215, 220, and 230).
    - - - Exception No. 2: For conductors installed in cable trays, the provisions of 392.11 shall apply.
    - - - Exception No. 3: Derating factors shall not apply to conductors in nipples having a length not exceeding 600 mm (24 in.).
    - - - Exception No. 4: Derating factors shall not apply to underground conductors entering or leaving an outdoor trench if those conductors have physical protection in the form of rigid metal conduit, intermediate metal conduit, or rigid nonmetallic conduit having a length not exceeding 3.05 m (10 ft) and if the number of conductors does not exceed four.
    - - - Exception No. 5: Adjustment factors shall not apply to Type AC cable or to Type MC cable without an overall outer jacket under the following conditions:
    - - - - (1) Each cable has not more than three current-carrying conductors.
    - - - - (2) The conductors are 12 AWG copper.
    - - - - (3) Not more than 20 current-carrying conductors are bundled, stacked, or supported on “bridle rings.”
    - - - - - A 60 percent adjustment factor shall be applied where the current-carrying conductors in these cables that are stacked or bundled longer than 600 mm (24 in.) without maintaining spacing exceeds 20.

    Being as 12-2-2 is already derated ... why derate it again for the same reason (yes, it would still require derating for ambient if the cables went into the typical vented attic which gets quite hot, but not if they went into a sealed attic with spray foam insulation on the underside of the roof deck).

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  45. #110
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Jerry Peck View Post
    I would not even attempt to try to convince my 6 year-old granddaughter of the above.

    I believe ... yes, I believe ... the intent was in reference to 4 conductors as in 2- 12-2 or 14-2 NM cables. And not necessarily to 12-2-2 NM cables because 12-2-2 cables *already* require derating simply by being 12-2-2 and having 4 current carrying conductors within the same cable. If those cables are *already* required to be derated in 310.15(B)(2):

    Being as 12-2-2 is already derated ... why derate it again for the same reason (yes, it would still require derating for ambient if the cables went into the typical vented attic which gets quite hot, but not if they went into a sealed attic with spray foam insulation on the underside of the roof deck).
    Excellent point about the 4 wire cables already requiring derating for the 4 CCC's in the cable.

    So the only scenario left that muddies the waters is two 3-wire cables which could be 4, 5 or 6 CCC's and derating would not apply in the sealed hole.


  46. #111
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Quote Originally Posted by Robert Meier View Post
    Excellent point about the 4 wire cables already requiring derating for the 4 CCC's in the cable.

    So the only scenario left that muddies the waters is two 3-wire cables which could be 4, 5 or 6 CCC's and derating would not apply in the sealed hole.
    Robert,

    Same section applies to that the same way:
    - a) If the 3-wire is a MWBC, then there are only 2 current carrying conductors, which means it is no different than 2-wire NM with regard to derating.
    - b) If there are 3 current carrying conductors in that 3-wire cable, then where it the neutral for the other hot conductor ... unless it is a switch leg run to a combination switch switch receptacle outlet which is supplied with a hot-neutral-switch leg from a lighting outlet box which is supplied with a hot-neutral. The switch leg is carrying the same current as the hot until a load is placed on the receptacle outlet (this is one example of what could be wired with that 3-wire and have 3 current carrying conductors).

    Most likely, with 2 3-wire NM cables, you would have only two current carrying conductors in each cable, and only 4 current conductors in those two NM cables - this would be the most likely scenario.

    In b) above you could have 5 or 6 current carrying conductors if you wired two separate combination switches that way and ran both NM cables through the same hole in the top plate. This would be highly unlikely, I would suggest.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  47. #112
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Jerry Peck View Post
    Robert,

    Same section applies to that the same way:
    - a) If the 3-wire is a MWBC, then there are only 2 current carrying conductors, which means it is no different than 2-wire NM with regard to derating.
    - b) If there are 3 current carrying conductors in that 3-wire cable, then where it the neutral for the other hot conductor ... unless it is a switch leg run to a combination switch switch receptacle outlet which is supplied with a hot-neutral-switch leg from a lighting outlet box which is supplied with a hot-neutral. The switch leg is carrying the same current as the hot until a load is placed on the receptacle outlet (this is one example of what could be wired with that 3-wire and have 3 current carrying conductors).

    Most likely, with 2 3-wire NM cables, you would have only two current carrying conductors in each cable, and only 4 current conductors in those two NM cables - this would be the most likely scenario.

    In b) above you could have 5 or 6 current carrying conductors if you wired two separate combination switches that way and ran both NM cables through the same hole in the top plate. This would be highly unlikely, I would suggest.
    Yup, the switch leg scenario was exactly what I was thinking.


  48. #113
    Join Date
    Feb 2011
    Location
    Upstate N.Y.
    Posts
    116

    Default Re: Bunching Romex

    Per Peck and possibly Watson who just can't seem to spell a persons name correctly, we should be wiring all houses with #6 NM cable after all their deratings are applied for "bundling, temperature, etc."

    I'd be curious to hear from any electrical contractors whom have been subjected to what I consider this type of unreasonable demands as it regards "bundling derating and temperature derating."

    The pictures that started this thread, albeit a little sloppy, would not be subject to derating by any inspector in my area and again, if applied per the above scenarios, #6 NM cable would be required.

    Talk about driving up the cost of construction!


  49. #114
    Join Date
    Sep 2007
    Location
    Fredericksburg, VA
    Posts
    885

    Default Re: Bunching Romex

    For a change of pace - I almost fell over when I saw this installation. It's very rare in this area to see something done this well. The electrician actually plastic standoffs to maintain spacing between cables. It may look like the cables are together but there is around 1/4" between each. Okay, a little closer between standoffs due to cable sag.

    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images
    The above statements are expressed solely as my opinion and in all probability will conflict with someone else's.
    Stu, Fredericksburg VA

  50. #115
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,243

    Default Re: Bunching Romex

    Stuart,

    Make sure they fireblock those open gaps at the top of the wall in the first photo where the concealed spaces between the studs communicate with the space above.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  51. #116
    Erik Pendleton's Avatar
    Erik Pendleton Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Jerry Peck View Post
    9 two-conductor cables means 18 current carrying conductors, and 10-20 current carrying conductors is derated to 50%.

    12 NMB is derated from 30 amps and 14 NMB is derated from 20 amps, so, presuming no derating for ambient temperature (i.e., not in an attic for example), 12 NMB would have a 15 amp rating (not suitable for anything greater than a 15 amp breaker) and 14 NMB would have a 10 amp rating (not suitable for anything at all basically).

    Now, if *any portion* of the any one of those circuits goes through an attic, than that entire circuit also needs to be derated for ambient temperature, and if we presume a typical 125 degree attic, the derate rating is further derated to 76%, which would make 12 NMB derated to 11.6 amps (not suitable for anything at all basically), and 14 NMB derated to 7.6 amps (making it a wasted used of copper not suitable for anything).

    And, if the attic temperature is higher than 131 degree (and up to 140 degrees) the ambient derating factor is 0.71 instead of 0.76, and if the attic temperatures reach 141 degrees to 158 degrees, the derating factor is 0.58.

    What really kills bundling and lack of maintaining space is having to derate for ambient *and* more than 3 conductors, derating for more than 3 conductors is bad enough.
    This doesn't seem right. The bundling and ambient are not in the same area. If they were bundled in the attic, I would agree. If the derating instances are in separate areas, it makes sense to use the full ampacity to derate each instance, and go with the resulting lowest amapacity.

    Or is there a reference that says that all derating instances are cumulative? What if a wire went to the attic for 10 ft, returned to conditioned space for 10ft and then returned to the attic for 10ft? Would you derate it twice? Or if it were bundled for 3ft, unbundled for 50ft then rebundled for 3ft? Would you derate it twice?

    Doesn't seem logical.


  52. #117
    Join Date
    Oct 2008
    Location
    Tulsa, OK
    Posts
    544

    Default Re: Bunching Romex

    If the conductors are both bundled and run through a high ambient temperature, the NEC requires both adjustments be made for those conductors affected. If part of the conductors only are bundled or are only ran through a higher temperature, only that single adjustment needs to be made. Both conditions add heat to the conductor as does the current flow. Since we are protecting the insulation (which is temperature rated and the weak link, usually) all adjustments need to be applied that the conductor is exposed to. There is not one specific statement that states this and that is one reason why the NEC is NOT a training manual..The other things to consider are the temperature limitations of the terminations, splices, raceway, etc..


    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  53. #118
    Erik Pendleton's Avatar
    Erik Pendleton Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Roland Miller View Post
    If the conductors are both bundled and run through a high ambient temperature, the NEC requires both adjustments be made for those conductors affected. If part of the conductors only are bundled or are only ran through a higher temperature, only that single adjustment needs to be made. Both conditions add heat to the conductor as does the current flow. Since we are protecting the insulation (which is temperature rated and the weak link, usually) all adjustments need to be applied that the conductor is exposed to. There is not one specific statement that states this and that is one reason why the NEC is NOT a training manual..The other things to consider are the temperature limitations of the terminations, splices, raceway, etc..
    I just don't buy that. Bundling causes localized heating. If a bundle of wires heats, the effects of that heat won't be carried to a remote location and other local effects remote from the bundle won't affect the bundle either.

    Without some definitive guidance on this I would say that combining localized adjustments is wrong.


  54. #119
    Erik Pendleton's Avatar
    Erik Pendleton Guest

    Default Re: Bunching Romex

    In fact from the NEC:

    "Exception: Where two different ampacities apply to adjacent portions of a circuit, the higher ampacity shall be permitted to be used beyond the point of transition, a distance equal to 3.0 m (10 ft) or 10 percent of the circuit length figured at the higher ampacity, whichever is less."

    To me this says after 10 ft the limit is no longer cumulative. Agreed?



  55. #120
    Join Date
    Oct 2008
    Location
    Tulsa, OK
    Posts
    544

    Default Re: Bunching Romex

    Quote Originally Posted by Erik Pendleton View Post
    In fact from the NEC:

    "Exception: Where two different ampacities apply to adjacent portions of a circuit, the higher ampacity shall be permitted to be used beyond the point of transition, a distance equal to 3.0 m (10 ft) or 10 percent of the circuit length figured at the higher ampacity, whichever is less."

    To me this says after 10 ft the limit is no longer cumulative. Agreed?

    This exception applies when the termination temperature limitation is lower then the ampacity of the conductor. When this occurs, after 10 feet you can use the higher ampacity of the conductor. So NO I don't agree. This is why it is not a training manual..

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  56. #121
    Erik Pendleton's Avatar
    Erik Pendleton Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Roland Miller View Post
    This exception applies when the termination temperature limitation is lower then the ampacity of the conductor. When this occurs, after 10 feet you can use the higher ampacity of the conductor. So NO I don't agree. This is why it is not a training manual..
    "310.15 Ampacities for Conductors Rated 0–2000 Volts .15 Ampacities for Conductors Rated 0–2000 Volts.
    (A) General General.
    (1) Tables or Engineering Supervision. Ampacities for conductors shall be permitted to be determined by tables as provided in 310.15(B) or under engineering supervision, as provided in 310.15(C).
    FPN No. 1: Ampacities provided by this section do not take voltage drop into consideration. See 210.19(A), FPN No. 4, for branch circuits and 215.2(A), FPN No. 2, for feeders.
    FPN No. 2: For the allowable ampacities of Type MTW wire, see Table 13.5.1 in NFPA 79-2007, Electrical Standard for Industrial Machinery.
    (2) Selection of Ampacity. Where more than one calculated or tabulated ampacity could apply for a given circuit length, the lowest value shall be used.
    Exception: Where two different ampacities apply to adjacent portions of a circuit, the higher ampacity shall be permitted to be used beyond the point of transition, a distance equal to 3.0 m (10 ft) or 10 percent of the circuit length figured at the higher ampacity, whichever is less."

    I think you are wrong.



  57. #122
    Join Date
    Oct 2008
    Location
    Tulsa, OK
    Posts
    544

    Default Re: Bunching Romex

    Erik--post some examples and show us how it works. I think you will find your assumption won't hold up..

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  58. #123
    Erik Pendleton's Avatar
    Erik Pendleton Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Roland Miller View Post
    Erik--post some examples and show us how it works. I think you will find your assumption won't hold up..
    I think I already did........

    Bundled wires in basement for 3 feet. One of those wires then travels through the house, say 30 feet to attic with 130F ambient.

    My understanding is that these two adjustment issues should be considered individually as the bundle in the basement will not impact the temperature 30 ft away. Therefore derate based on one factor, the one that is most severe.

    If the bundle were in the attic, then you would have to derate for both factors.


  59. #124
    Join Date
    Oct 2008
    Location
    Tulsa, OK
    Posts
    544

    Default Re: Bunching Romex

    https://www.youtube.com/watch?v=7kU0VJhwtzs

    You are stretching the application of this article. Your example is deficient. Heat does transfer to other parts of the circuit (is not localized).

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  60. #125
    Erik Pendleton's Avatar
    Erik Pendleton Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Roland Miller View Post
    https://www.youtube.com/watch?v=7kU0VJhwtzs

    You are stretching the application of this article. Your example is deficient. Heat does transfer to other parts of the circuit (is not localized).
    Really? You propose that video as support for your opinion?

    That video doesn't address this issue at all so if that is the best you can come up with, then I am more certain you are wrong.


  61. #126
    Join Date
    Oct 2008
    Location
    Tulsa, OK
    Posts
    544

    Default Re: Bunching Romex

    Quote Originally Posted by Erik Pendleton View Post
    Really? You propose that video as support for your opinion?

    That video doesn't address this issue at all so if that is the best you can come up with, then I am more certain you are wrong.
    If the conductors are both bundled and run through a high ambient temperature, the NEC requires both adjustments be made for those conductors affected. If part of the conductors only are bundled or are only ran through a higher temperature, only that single adjustment needs to be made. Both conditions add heat to the conductor as does the current flow. Since we are protecting the insulation (which is temperature rated and the weak link, usually) all adjustments need to be applied that the conductor is exposed to. There is not one specific statement that states this and that is one reason why the NEC is NOT a training manual..The other things to consider are the temperature limitations of the terminations, splices, raceway, etc..

    I don't believe you even read what I posted because you decided I disagree with you. Since you don't have the ability to discern meaning from the written word or even a video that applies, why would I think you can read the NEC and get anything but more questions. Then argue about something you don't know much about.

    Try re-reading what I said. Maybe consult an english/grammar expert and then see how it applies to you question.

    My statement is code correct as written.


    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  62. #127
    Join Date
    Oct 2008
    Location
    Tulsa, OK
    Posts
    544

    Default Re: Bunching Romex

    (2) Selection of Ampacity. Where more than one ampacity
    applies for a given circuit length, the lowest value shall be
    used.(2014 NEC)

    This is all you need to know. The exception does not apply to your question.

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  63. #128
    Erik Pendleton's Avatar
    Erik Pendleton Guest

    Default Re: Bunching Romex

    Quote Originally Posted by Roland Miller View Post
    (2) Selection of Ampacity. Where more than one ampacity
    applies for a given circuit length, the lowest value shall be
    used.(2014 NEC)

    This is all you need to know. The exception does not apply to your question.
    I apologize - I read your comments as disagreeing with me (particularly where you said give an example and my logic wouldn't hold up).

    But now I see you seem to be agreeing with me:

    The lowest ampacity value is to be used. So if as in my example, 3 ampacities apply (ignoring termination constraints for this example): 1. bundle adjusted for the bundled portion, 2. unadjusted for unbundled portion in normal temperature (basically the living space of the house), and 3. ambient temp adjusted for the high ambient of the attic run.

    Per your NEC quote above, the lowest ampacity of the 3 should be applied to all of the circuit.

    This makes sense and is the position I was advocating.

    If the bundle were in the attic - then you would have to apply both factors to that portion of the circuit and apply that much lower ampacity to the entire circuit.

    This also makes sense and is also the position I was advocating.

    Again, I apologize if you were agreeing with the entire time. Forum communications are sometimes not as clear as we believe. Sometimes it is better to preface a statement with "Yes, you are correct" or "No, that is incorrect".

    Thanks


  64. #129
    Join Date
    Oct 2008
    Location
    Tulsa, OK
    Posts
    544

    Default Re: Bunching Romex

    Quote Originally Posted by Erik Pendleton View Post
    I apologize - I read your comments as disagreeing with me (particularly where you said give an example and my logic wouldn't hold up).

    But now I see you seem to be agreeing with me:

    The lowest ampacity value is to be used. So if as in my example, 3 ampacities apply (ignoring termination constraints for this example): 1. bundle adjusted for the bundled portion, 2. unadjusted for unbundled portion in normal temperature (basically the living space of the house), and 3. ambient temp adjusted for the high ambient of the attic run.

    Per your NEC quote above, the lowest ampacity of the 3 should be applied to all of the circuit.

    This makes sense and is the position I was advocating.

    If the bundle were in the attic - then you would have to apply both factors to that portion of the circuit and apply that much lower ampacity to the entire circuit.

    This also makes sense and is also the position I was advocating.

    Again, I apologize if you were agreeing with the entire time. Forum communications are sometimes not as clear as we believe. Sometimes it is better to preface a statement with "Yes, you are correct" or "No, that is incorrect".

    Thanks
    Apology accepted. I also apologize for my sometimes abrupt and abrasive postings. Yes--you have it the way I would apply the NEC. I didn't say Yes or No because I was not sure of your position since you asked me to post the code reference. Sometimes people sign up and ask the "loaded" questions to further pursue a disagreement outside the forum.

    OBTW--welcome to this forum. You will find some of us (me included) have strong opinions. Hopefully you will find things to add and have the staying power to keep posting..

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

Page 2 of 2 FirstFirst 12

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •