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  1. #1
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    Question De-rating conductor

    Fireplace flue was run up a chase and elbowed over before running up through the second floor. There are several conductors in close proximity of the flue. At least 3 are bunched together and pretty close to the flue. I wrote it up that the AHJ should take another look but do you think they should be moved or just De-rated or nothing?

    Many Thanks

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  2. #2
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    Default Re: De-rating conductor

    I hope that flue is for gas logs only, looks too small for a wood buring prefab metal fireplace.

    Derating is not an option here. The cables need to be moved at least one inch from the pipe. Will they melt if left as is? Probably not unless the gas logs were run for many hours.


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    Default Re: De-rating conductor

    The cables are over 1" from the gas flue from the fireplace. Why wouldn't de-rating come into account. If the conductors heat up from the flue above there rating should it not be de-rated. If de-rating needs applied for bundled wires because of the heat I would think this flue would be like bundling and the three conductors are slightly bundled to add to the fact?
    Just curious if anyone thinks this way besides my little pea brain

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  4. #4
    Tim Netzley's Avatar
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    Default Re: De-rating conductor

    I am a Master Electrician. Derating would not come into account because the NM sheathing and the THHN insulation over the wiring inside the sheathing are neither rated for the type of heat that would likely be produced here. However, if I'm seeing this right, I would not think that more than a 2X4 or even a 1X4 to separate the wiring from the pipe would do. Easy fix since this is more than likely a double walled duct rated for the application. Only you can tell by being there to see it. I hope that helps.


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    Default Re: De-rating conductor

    Quote Originally Posted by Tim Netzley View Post
    I am a Master Electrician. Derating would not come into account because the NM sheathing and the THHN insulation over the wiring inside the sheathing are neither rated for the type of heat that would likely be produced here.
    Ahh ... Master Electrician ... derating WOULD come into account ... derating may or may not lead to derating below the 15 and 20 amp those are likely protected at.

    Do those same circuits run up into the attic too? If so, with ambient derating (which ALWAYS takes place and IS WHY the conductor insulation is 90 degree C) the derating taken for lack of maintaining spacing MAY show the need for an actual reduction in the overcurrent protection.

    However, if I'm seeing this right, I would not think that more than a 2X4 or even a 1X4 to separate the wiring from the pipe would do. Easy fix since this is more than likely a double walled duct rated for the application. Only you can tell by being there to see it. I hope that helps.
    However, here comes a question I do not believe has been addressed anywhere: Let us presume that the conductor are moved to be the required 1" from the vent - we will assume that as a "given", now, what temperature rise does that vent have on that space where the conductors are? Doe it rise the ambient derating above the attic ambient derating temperature? My guess and answer would be "Probably not, especially if you are going with an attic ambient derating of 132-140 degrees F as I doubt the ambient in that area would exceed that temperature, and that attic temperature range requires an ambient derating factor of 0.71.

    With the 90 degree C insulation rating of 30 amps for the #12 AWG NM-B cable, that gives us a derated ampacity of 21.3 amps - which is precisely why 90 degree C conductor insulation is used in NM-B ... to allow for that attic temperature ambient derating.

    Now, though, we are only starting at 21.3 amps when derating for lack of maintaining spacing.

    I see 3 2-conductor NM-B cables in a couple of bundles/lack of maintaining spacing groups, that makes 6 current carrying conductors. The derating factor for 4-6 current carrying conductors is 0.80, thus 21.3 amps is derated to 17.4 amps.

    The above means that up to 6 current carrying conductors in #12 AWG NM-B can be derated for attic ambient of 132-140 degrees F and for lack of maintaining spacing is derated to 17.4 amps.

    Now, IF those branch circuits are for specific uses, such as lighting, smoke detectors, etc., and not for multioutlet branch circuits (to multiple outlets, i.e., multiple receptacles), then 17.4 amps, which is greater than 15 amps, is thus allowed to be on the next higher standard overcurrent protective device rating is 20 amps.

    And IF those branch circuits are for multiple outlet branch circuits (i.e., are for the receptacle outlets in the various rooms), then those derated circuits would need to be protected at not exceeding their derated rating, i.e., not exceeding 17.4 amps, and the next LOWER standard overcurrent device rating of 15 amps.

    Simply put, every Master Electrician should know this.

    I am only pointing this out as the Master Electrician specifically pointed out to us that he was a "Master Electrician".

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    Default Re: De-rating conductor

    Jerry I sure hope I am close to being as smart as you when I grow up. I was so fixated on the picture you see and the clients distractions I never checked where those conductors terminate too.

    As always I'm in awh

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    Default Re: De-rating conductor

    Quote Originally Posted by Mike Schulz View Post
    Jerry I sure hope I am close to being as smart as you when I grow up. I was so fixated on the picture you see and the clients distractions I never checked where those conductors terminate too.

    As always I'm in awh


    Mike, you might be in "awh" but I'm in ahhhhhhhhhaha! LMAO


  8. #8
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    Default Re: De-rating conductor

    So, in the end of all of the details Jerry, we find that in all likelihood, the 20A OCPD maximum allowed in residential applications will thus be a sufficient built-in derating. Therefore, derating any further will almost certainly not be needed. I'm glad we agree. I wasn't trying to give a class.


  9. #9
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    Default Re: De-rating conductor

    By the way, I was merely pointing out the fact that I'm a Master Electrician in an attempt to help. I didn't think explaining who you are here was a crime, Jerry, Construction/ Litigation Consultant, Mr. Ask the Code Man. Please forgive my sin.


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    Default Re: De-rating conductor

    Bruce it was that Southern draw thingy is why i wrote it that way

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    Default Re: De-rating conductor

    Quote Originally Posted by Tim Netzley View Post
    So, in the end of all of the details Jerry, we find that in all likelihood, the 20A OCPD maximum allowed in residential applications will thus be a sufficient built-in derating. Therefore, derating any further will almost certainly not be needed. I'm glad we agree. I wasn't trying to give a class.
    Tim,

    "Therefore, derating any further will almost certainly not be needed."

    I thought the end result was clear, but apparently not.

    " I'm glad we agree."

    We do NOT agree, that is, unless you agree that the NM-B cables supplying multiple outlet branch circuits IS NOT allowed to be taken to the next higher standard rating, but MUST be taken to the next lower standard rating.

    Quote Originally Posted by Tim Netzley View Post
    By the way, I was merely pointing out the fact that I'm a Master Electrician in an attempt to help. I didn't think explaining who you are here was a crime, Jerry, Construction/ Litigation Consultant, Mr. Ask the Code Man. Please forgive my sin.
    Explaining who you are is not a crime, and in fact is helpful.

    But stating (not explaining) "I am a Master Electrician." in a stand alone sentence can be taken as, was taken as, "Therefore I KNOW what non-master electricians do not know".

    And your posted ended up incorrect.

    It is like an engineer standing up and saying "I am an engineer."

    The next words out of their mouth now need to be based on solid engineering as that is what it will be taken as, and, more likely than not, that was their intent - to make themselves sound more knowledgeable.

    Just pointing that out.

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  12. #12
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    Default Re: De-rating conductor

    Thank you for clarifying, Jerry. Now back to code, from this picture alone, without any assumptions past it, I see no need for derating lower than the 20A max allowed for 12AWG in residential applications. If, however, upon further investigation, as you point out the possibility, we find further cause for consideration, I would be inclined to agree with you. But, wouldn't you say that by the picture alone, there is nothing more that can be known nor therefore warranted?


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    Default Re: De-rating conductor

    Sorry for not getting more information. After visualizing and pondering it for awhile those conductors closest to the flue I believe are running to the kitchen but not verified yet. My client is going to check for me :-)

    When you see stuff like this you just think to yourself wtf. Why the electrician couldn't move those close ones just a Little further away.

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    Default Re: De-rating conductor

    In all honesty we can not tell if there is a need to derate the conductors shown in the picture.
    There is not enough information provided to make such a judgment,and by doing so we would be guilty of playing the "WHAT IF" game.

    Do these NM cables pass through the same opening in wood framing That is to be fire stopped,caulked, sealed with foam,or insulation ?
    Do these NM Cables come in contact with with thermal insulation?

    Just because the NM Cables are running up a wall cavity together does not require them to be classified as bundled and require derating.
    Read the 2008 NEC article 334.80, paragraph 2and 3 carefully. ( paragraph 1 explains how to derate)
    If you are running up the inside walls, with no insulation, and the cables do not come through a opening in the framing that is to caulked/firestopped there is no derating required by the NEC


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    Default Re: De-rating conductor

    They are passing through a ceiling through I joist. Fire stopped where needed through top plates. No insulation in the ceiling area except where they will be coming through the garage (Panel Location)

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  16. #16
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    Default Re: De-rating conductor

    Aptly put, Ken.


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    Default Re: De-rating conductor

    Quote Originally Posted by ken horak View Post
    In all honesty we can not tell if there is a need to derate the conductors shown in the picture.
    Actually, we can tell, and it is easy to tell that just be looking at that photo, provided ...
    There is not enough information provided to make such a judgment,and by doing so we would be guilty of playing the "WHAT IF" game.
    ... provided they are run like that for more than 24" - that is the only "WHAT IF" in that photo, that and the temperature of the attic, thus the prefacing with the attic temperature used.

    Just because the NM Cables are running up a wall cavity together does not require them to be classified as bundled and require derating.
    You are correct that they do not need derating "Just because the NM Cables are running up a wall cavity together", it is HOW they are run in that wall cavity together which makes them in need of derating.


    Read the 2008 NEC article 334.80, paragraph 2and 3 carefully. ( paragraph 1 explains how to derate)
    If you are running up the inside walls, with no insulation, and the cables do not come through a opening in the framing that is to caulked/firestopped there is no derating required by the NEC
    Here is that section, and, yes, YOU do need to read it carefully. The two paragraphs you directed us to ARE IN ADDITION TO the first paragraph, not instead of it.

    - 334.80 Ampacity. (bold and underlining are mine)
    - - 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 60C (140F) conductor temperature rating. The 90C (194F) rating shall be permitted to be used for ampacity derating purposes, provided the final derated ampacity does not exceed that for a 60C (140F) rated conductor. The ampacity of Types NM, NMC, and NMS cable installed in cable tray shall be determined in accordance with 392.11. (Jerry's note: Ken, in case you missed that part, it says SHALL BE DETERMINED IN ACCORDANCE WITH 310.15. The following two paragraphs ARE IN ADDITION TO what is stated in 310.15.)
    - - 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. (Jerry's note: This paragraph is IN ADDITION TO the requirements of 310.15.)
    - - 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's note: This paragraph is IN ADDITION TO the requirements of 310.15.)

    Now, go back and apply 310.15 ... AND THEN you will see enough in that photo to understand that derating is needed as I described ... AND THEN ... apply the above two paragraphs you pointed out.

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    Default Re: De-rating conductor

    If they pass through the fire stopped holes in groups of 3 or more the yes derating is in order. The same goes if run in the insulation.
    This issue has become a majorly confused issue.


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    Default Re: De-rating conductor

    Quote Originally Posted by ken horak View Post
    If they pass through the fire stopped holes in groups of 3 or more the yes derating is in order. The same goes if run in the insulation.
    Yes, and IN ADDITION TO that, they must ALSO be derated in accordance with 310.15.

    The reason those were added is that, regardless HOW LONG the distance is where the conductors pass through the fire stopped holes, EVEN WHEN less than 24", they are now required to be derated. Previously that was not code applicable for lengths 24" and under, but inspections, testing, and physical evidence have revealed that it is necessary *regardless* how short the length of that is that it needs to be derated.

    This issue has become a majorly confused issue.
    As evidenced by your post and that of Tim.

    Just because the new sections were added does not mean that the previous and still existing section is no longer applicable, that being 310.15.

    It is still applicable.

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  20. #20
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    Default Re: De-rating conductor

    We here in Montana have not yet adopted the 2008 edition of the NEC and are still working out of the 2005. I would only suggest we all know what our State and/ or local requirements are before advising clients. The '05 doesn't have a stipulation re: how many cables can run through bored holes. The '08 'fixes' this. In my professional opinion, untied cables run adjacent to each other through an open space should not be considered bundled by intent. If they are held together by ties, then the 24" rule Jerry referred to shall be introduced. Judgment must be exercised here, however, as to tightness and a space that may be affected, as is this one, by other components such as a stove flu.

    **Memorial Day - To all of those who did and do, and to those who've sacrifices for other to, I tip my hat and raise my glass. With love and pride, this one's for you.**


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    Default Re: De-rating conductor

    Quote Originally Posted by Tim Netzley View Post
    In my professional opinion, untied cables run adjacent to each other

    Tim,

    There are two things which are addressed by the code: bundling (tied cables) and lack of maintaining spacing (untied cables) which are run closely together with each other.

    That photo show, from left to right:
    - *3* untied cables creating lack of maintaining spacing
    - *2* untied cables creating lack of maintaining spacing
    - *1* untied cables wondering back and forth
    - *2* untied cables creating lack of maintaining spacing
    - *3* untied cables creating lack of maintaining spacing

    Even the *2* untied cables creating lack of maintaining spacing creates the condition where there are 4 current carrying conductors in 2 multiconductor cables which spacing has not been maintained and therefore even those two bundles (for lack of a better word to use to describe the distinctly separate lack of maintaining spacing runs) of 2 lack of maintaining spacing cables requires derating.

    And, after first derating for ambient (when they go through an attic or other hot area), and when they feed branch circuits with more than one receptacle on the branch circuit, then they will need to be derated, and quite possibly, as I've shown, derated down to the next breaker size.

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    Default Re: De-rating conductor

    .....

    Last edited by ken horak; 03-30-2012 at 05:20 PM.

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    Default Re: De-rating conductor

    Post the article that clearly states that one must derate for a branch circuit that has more then one receptacle.


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    Default Re: De-rating conductor

    Quote Originally Posted by ken horak View Post
    The original Post said NOTHING about an attic. You brought that into the conversation.
    Matter of fact it states that the flue goes up a chase then elbowed over before going up through the second floor.
    How do we know that the cables go into an attic? WE DON"T. YOU ASSUMED
    Ken,

    You need to go back and read my post again, and, oh heck, I'll just quote it here for you so you can see THE CONDITIONS I STATED I was working with.

    Quote Originally Posted by Jerry Peck View Post
    Do those same circuits run up into the attic too? If so, with ambient derating (which ALWAYS takes place and IS WHY the conductor insulation is 90 degree C) the derating taken for lack of maintaining spacing MAY show the need for an actual reduction in the overcurrent protection.
    Now, given those given conditions, and it was up to Mike to state those conditions did or did not apply, THOSE CONDITIONS were was I stated "If so", then the derating as I stated would apply.

    If those conductors, NONE of them, go into the attic, then there is no attic derating.

    That is an obvious conclusion to reading my post about the attic ambient temperature derating statement.

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    Default Re: De-rating conductor

    Quote Originally Posted by ken horak View Post
    Post the article that clearly states that one must derate for a branch circuit that has more then one receptacle.

    - 240.4 Protection of Conductors.
    - - Conductors, other than flexible cords, flexible cables, and fixture wires, shall be protected against overcurrent in accordance with their ampacities specified in 310.15, unless otherwise permitted or required in 240.4(A) through (G).
    - - - (A) Power Loss Hazard. Conductor overload protection shall not be required where the interruption of the circuit would create a hazard, such as in a material-handling magnet circuit or fire pump circuit. Short-circuit protection shall be provided.
    - - - - FPN: See NFPA 20-2007, Standard for the Installation of Stationary Pumps for Fire Protection.
    - - - (B) Devices Rated 800 Amperes or Less. The next higher standard overcurrent device rating (above the ampacity of the conductors being protected) shall be permitted to be used, provided all of the following conditions are met:
    - - - - (1) The conductors being protected are not part of a multioutlet branch circuit supplying receptacles for cord-and-plug-connected portable loads.
    - - - - (2) The ampacity of the conductors does not correspond with the standard ampere rating of a fuse or a circuit breaker without overload trip adjustments above its rating (but that shall be permitted to have other trip or rating adjustments).
    - - - - (3) The next higher standard rating selected does not exceed 800 amperes.

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  26. #26
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    Default Re: De-rating conductor

    As Mike said these are not entering the attic. Without any assumptions, and only givens from Mike's long lost query, we do not see that any derating below the 20A requirement is yet necessary.
    Article 240.4 does not address derating other than to reference 310.15 that does. I believe the reason for 240.4(B)(1) should be obvious. Without the exclusion the requirement for these circuits of 12AWG at 20A and 14AWG for 15A would be contradicted if no derating is in play.


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    Default Re: De-rating conductor

    Quote Originally Posted by Tim Netzley View Post
    Derating would not come into account because the NM sheathing and the THHN insulation over the wiring inside the sheathing are neither rated for the type of heat that would likely be produced here.
    Quote Originally Posted by Tim Netzley View Post
    As Mike said these are not entering the attic. Without any assumptions,
    That heat replaces the attic heat, thus ambient derating would still be required.

    Without knowing the heat in that area (which both you and I have referred to at various time in various ways) and without KNOWing whether OR NOT those also go into the attic, only suppositions can be made.

    We have both made and stated our suppositions, mine are allowing for worst case (EITHER the attic - which is unknown - OR the heat from that vent).

    You are stating outright that no derating is required.

    I am stating that, under the conditions stated in the supposition, derating is required.

    Mike will need to be the one to clear that up, but there is visible evidence regarding the NM-B cables and the vent being in a hotter than normal environment, possibly even equating to attic temperatures.

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    Default Re: De-rating conductor

    .....

    Last edited by ken horak; 03-30-2012 at 05:19 PM.

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    Default Re: De-rating conductor

    Quote Originally Posted by ken horak View Post
    Article 240.4 says absolutely zero about one having to derate for more then one receptacle on a circuit.
    This article allows one to utilize the next larger overcurrent device when one has a calculated load that does not correspond to a standard ampere rating, like a service for example. look at 500kcmil thhn table 310.16 , 75 degree column, copper, it's rated for 380 amperes. This article allows the electrician to use a 400 ampere breaker with this cable.

    Receptacles on the other hand-
    table 210.24 summarizes the requirements for overcurrent and conductor sizing for branch circuits with 2 or more outlets. This table overrides 240.4.

    Sorry 240.4 = nothing about derating for more then one receptacle on a circuit. It just states that one must follow 310.15. which does not state to derate for more then one receptacle on a circuit either.
    Ken,

    I don't know what you've been smoking, but I do know what you have not been reading ... the code.

    I will try to simplify it for you this time: (underlining, bold, red, etc., any and all highlighting ... is mine)
    - 240.4 Protection of Conductors. (Jerry's note to Ken: This section is about "Protection of Conductors." Not just the conductors you are referring to, but *all* *conductors*. Its requirements and allowances supersede those in 310.15. *If not for this section*, one *WOULD NOT* be allowed to install overcurrent protection on conductors with a rating which was higher than the rating of the conductors themselves. One would need to determine the rating of the conductors as stated in 310.15 and then select the next lower overcurrent rating which would protect the conductors to within their rating. Fortunately, there is this section, and it allows for the increasing in rating of the overcurrent protection device rating *AS ALLOWED WITHIN THE CONDITIONS STATED BELOW*.)
    - - Conductors, other than flexible cords, flexible cables, and fixture wires, shall be protected against overcurrent in accordance with their ampacities specified in 310.15, unless otherwise permitted or required in 240.4(A) through (G). (Jerry's note to Ken: Notice the reference to 310.15, then notice the "unless otherwise ... required" by this section, that means that this section supersedes the permitted or required allowances of 310.15)
    - - - (A) Power Loss Hazard. Conductor overload protection shall not be required where the interruption of the circuit would create a hazard, such as in a material-handling magnet circuit or fire pump circuit. Short-circuit protection shall be provided. (Jerry's note to Ken: Neither (A) nor its FPN are applicable to the discussion.)
    - - - - FPN: See NFPA 20-2007, Standard for the Installation of Stationary Pumps for Fire Protection.
    - - - (B) Devices Rated 800 Amperes or Less. The next higher standard overcurrent device rating (above the ampacity of the conductors being protected) shall be permitted to be used, provided all of the following conditions are met: (Jerry's note to Ken: This *allows* for the use of the next higher standard overcurrent rating above the ampacity of the derated conductors ... PROVIDED that *all* *of* *the following (1), (2), and (3) are met.)
    - - - - (1) The conductors being protected are not part of a multioutlet branch circuit supplying receptacles for cord-and-plug-connected portable loads. (Jerry's note to Ken: This is the precise section you are asking about, so read it and understand it carefully - (B) above says you are allowed to use the next higher standard ampacity overcurrent rating *as long as* *the branch circuit* *does not have* *multiple receptacle outlets on it* as those multiple receptacle outlets will be supplying unknown cord-and-plug-connected portable loads. In fact, what those receptacles are provided for - unknown cord-and-pug-connected portable loads. The code will allow the next higher standard rating for known loads, but not unknown loads. It really is quite simple, that simple.)
    - - - - (2) The ampacity of the conductors does not correspond with the standard ampere rating of a fuse or a circuit breaker without overload trip adjustments above its rating (but that shall be permitted to have other trip or rating adjustments). (Jerry's note to Ken: This is not applicable to the discussion.)
    - - - - (3) The next higher standard rating selected does not exceed 800 amperes. (Jerry's note to Ken: This is not applicable to the discussion.)

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  30. #30
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    Default Re: De-rating conductor

    If the required clearence from flammables is met, I don't think derating is an issue. If the wires are within that restricted space, derating is the least of our issues.

    Assuming that the opening in the wood defines / complies with clearance requirements, it looks like - at most - one wire is just barely on the border.

    Otherwise, in practical terms, you have 90 degree wire that has already been derated to 75 degree wire, and then further reduced from 25 amps to 20 amps. If that wire got hot enough to warrant further derating, the insulation would show it after even one use of the fireplace.

    One of the quirks of derating 'by code' is that the code assumes a circuit is sized to the load it supplies - hence the defining of the ampacity of a circuit according to the size of the breaker. The problem is that other parts of the code require certain circuits, regardless of load supplied, and that 'convenience' circuits have, by definition, undefined loads.

    For example, the furnace is required to be on it's own circuit - though that circuit might be supplying nothing bt an igniter (less than an amp).

    For the wires in the picture ... well, where's the temperature measurements? Derate based upon what? How about forgoing all the math, and just pushing the wires another inch to the side?

    Last edited by John Steinke; 05-26-2009 at 09:13 PM. Reason: Corrected typo where "3" was used instead of "2"

  31. #31
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    Default Re: De-rating conductor

    Quote Originally Posted by John Steinke View Post
    Otherwise, in practical terms, you have 90 degree wire that has already been derated to 75 degree wire, and then further reduced from 35 amps to 30 amps.

    .Huh?

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  32. #32
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    Default Re: De-rating conductor

    True, true, Mr. Horack. Jerry, the contact info is in the book for those that actually wrote the code. Check it out. They are accessible people.


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    Default Re: De-rating conductor

    Quote Originally Posted by ken horak View Post
    Mr. Peck,
    Why must you fall back on your old habit of being insulting and rude?
    Ken,

    Not being rude, just wanting you to share whatever it was you were smoking if it was that good.

    Lets keep this on a professional level and not be insulting.
    Okay, then start reading the code. It really is as simple as I am describing it to be.

    Also Should I choose not to reply to your next post it's not because I'm wrong and hoping it will just go away rather then admit it ( as you accused me of). It is because I chose not to keep replying to someone who will not admit when he is wrong and just distorts the facts,and insists on having the the last post right or wrong!
    Actually, *I* have, and do, admit it when I am wrong, however, *you* on the other hand, have been shown to have been wrong several times and refused to admit it. That sure is "keeping it professional", isn't it?

    I have done my best to show you what the code says about derating and how the code addressed derating, but when one is predisposed as you (from current and previous posts) to not derate anything for any reason, you simply will not understand what the code is saying and why it says what it does and why it addresses what it does.

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    Default Re: De-rating conductor

    Quote Originally Posted by Tim Netzley View Post
    Jerry, the contact info is in the book for those that actually wrote the code. Check it out. They are accessible people.
    Yep, I am aware of that and have talked to several people on different Code Making Panels at various times over the years.

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  35. #35
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    Default Re: De-rating conductor

    I could say the same in regards to the NEC. So, where does that leave us? The codeology principles espoused by myself and those of Mr. Horak are taught in electrical apprenticeship courses throughout the country. You obviously know a bunch of code. However, I don't think you will find too many licensed AHJs to agree with you. Good idea to be over-cautious? Yes. Requirement? No.


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    Default Re: De-rating conductor

    Quote Originally Posted by Tim Netzley View Post
    I don't think you will find too many licensed AHJs to agree with you.
    I know there is a lot of AHJ in Florida who do agree with me.

    Maybe Florida is just a head of the curve in enforcing the codes?

    I know some less populated areas of Florida are being dragged, kicking and screaming, into the present from the past. Maybe some less populated areas of the country are also behind the curve?

    I know in a recent (last year, I believe it was) survey to find out what edition of the NEC was adopted and being used by the various AHJs, and the oldest one I recall was one or two AHJ still using the 1984 NEC as their adopted NEC code they are enforcing - we are talking about a 25 year old code still being enforced.

    Yeah, I am sure that AHJ totally agrees with you and Ken. But I would not want to rest my laurels on AHJ using a 25 year old code as support and backup agreement for what I thought. In fact, I would distance myself from them if possible. But maybe that is just me.

    Florida has a statewide code and the local AHJ are required to enforce it.

    Good idea to be over-cautious? Yes. Requirement? No.
    Good idea - yes.

    Required - yes.

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  37. #37
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    Default Re: De-rating conductor

    Jerry, As far as I can see Florida is only a few months ahead of Montana in adoption of the 2008 edition of the NEC. Estimated date of full adoption for FL being 7/1/09? We in MT are in process as we have already decided to adopt it. Another similarity is in our procedure. The State here also mandates enforcement in local municipalities, unlike most States.
    Differences: We here understand how to have an intelligent debate without emotionalism getting in the way and coming through in snide and sophomoric rhetoric. My Philosophy professor taught me to walk away from such a person. I thus refuse to digress any further, but hope to continue to have healthy debate and discussion without the need to win, but learn from one another.
    You are an intelligent man, Jerry. Use your power for good. Keep it in your head. As for me, I'm done with you here.

    Tim


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    Default Re: De-rating conductor

    Quote Originally Posted by Tim Netzley View Post
    My Philosophy professor taught me to walk away from such a person.
    Obviously not, you kept coming back to put forth your side of the same stuff.

    Tim,

    We all learn from each other, but at times there will be someone who comes in and tries to convince all others that their way is the only way, and that is what you have tried to do.

    It is apparent that you do not like, or are not used to, resistance and opposing opinions to your ways. Sorry to have upset your apple cart with that needed and necessary resistance and opposing opinions. The simple fact that you were sounding like Ken should have been a clue to me, but at least you are not like John, and Ken is not either, John is from someplace else and only works with minimizing the code, at least based on his posts.

    Take care, and when you are ready we can debate this again. Or something else. Who knows, we may agree on the next thing, even Ken and I agree some times (John and I almost never , Whew!).

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    Default Re: De-rating conductor

    Quote Originally Posted by Jerry Peck View Post
    Obviously not, you kept coming back to put forth your side of the same stuff.

    Tim,

    We all learn from each other, but at times there will be someone who comes in and tries to convince all others that their way is the only way, and that is what you have tried to do.

    It is apparent that you do not like, or are not used to, resistance and opposing opinions to your ways. Sorry to have upset your apple cart with that needed and necessary resistance and opposing opinions.
    Isn't that the pot calling the kettle black?

    Jerry, how can we have a debate about bundling when the NEC does not define it? After all we can't call something a subpanel because it is undefined.


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    Default Re: De-rating conductor

    Quote Originally Posted by Jim Port View Post
    Jerry, how can we have a debate about bundling when the NEC does not define it? After all we can't call something a subpanel because it is undefined.
    Jim,

    The term "subpanel" is not in the code anywhere, defined or not.

    The term "bundling" was in the code, and, to top that off, you seem to have forgotten the other term I consistently use when the term "bundling" is used, and that term is in the code, it is "lack of maintaining spacing" (technically, the term used in the code is "WITHOUT maintaining spacing", I had changed it to "lack of maintaining spacing" to explain what was missing, i.e., "lack" of that spacing - however, I will need to try to make sure that I now say "without maintaining spacing - thank you for bringing that to my attention).

    Now, though, to clear you up on that and bring you up to date because, yet again, you did not go back and read the code before posting, I will post the 2005 NEC and 2008 NEC sections relating to that and you tell me which term has been removed. That should help clear up your question.

    From the 2005 NEC.
    (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 stacked or bundled longer than 600 mm (24 in.) without maintaining spacing 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.


    From the 2008 NEC.
    (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.

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    Default Re: De-rating conductor

    .....

    Last edited by ken horak; 03-30-2012 at 05:18 PM.

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    Default Re: De-rating conductor

    [quote=ken horak;86248]
    Quote Originally Posted by Jerry Peck View Post
    We all learn from each other, but at times there will be someone who comes in and tries to convince all others that their way is the only way, and that is what you have tried to do. /quote]

    Jerry look in the mirror and repeat your quote above. Your own quote fits you like glove

    Just an observation
    And I back mine up with the code and explain what it says, word by word, not what I want it to say by misdirecting others to someplace else which is not applicable.

    In those cases I try to convince all others that (Ken, make note of this difference in what you posted) "the code" says what it actually says and that is the way.

    Versus others who try to convince all others that (Ken, from what you posted that I said, notice the difference to the above) "their way" is the only way.

    Ken, did you spot the difference between what I was saying and what you were trying to say?



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    Default Re: De-rating conductor

    Thanks for the education Jerry and others. Client email me and said they are to the kitchen, and that is what I recalled when I was there. There is three conductors in that bunch at the flue. They run from the garage up the wall in the garage into the ceiling across the entire length of the home to the kitchen.
    P.S I really hate downsizing pictures for this sight. Where the heck did 198 KB come from anyway. Why can't we use the 320/200 or 480/640 or 600/800 or 1024/768 that most picture software comes with so we don't have to spend so much time getting the KB size right.

    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images
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  44. #44
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    Default Re: De-rating conductor

    Quote Originally Posted by Mike Schulz View Post
    Client email me and said they are to the kitchen, and that is what I recalled when I was there. There is three conductors in that bunch at the flue. They run from the garage up the wall in the garage into the ceiling across the entire length of the home to the kitchen.
    Okay, we take the attic ambient out of the picture and replace it with, as explained in posts above by Tim and myself, the ambient from the vent.

    The end result may (the ambient temperature being unknown, but we do know it will definitely be elevated above surrounding ambient and if the vent had not been there), and, does that get drywalled? If so, that makes that issue even worse as it traps the heat in there.

    P.S I really hate downsizing pictures for this sight. Where the heck did 198 KB come from anyway. Why can't we use the 320/200 or 480/640 or 600/800 or 1024/768 that most picture software comes with so we don't have to spend so much time getting the KB size right.
    Brian has some graphic compression software installed which will probably allow you to use at least 640x480, maybe even a higher resolution.

    Try to see what size file loads, too big and his compression software kicks it back as too big, otherwise it will be compressed down to whatever Brian has it set to.

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  45. #45
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    Default Re: De-rating conductor

    If you are concerned, Mike, is this space vented (such as an attached vented eve)? You could suggest a piece of sheetrock, if there is room, between the TJIs to isolate the space between the cabling and the flu (like is done for can lights in some cases).


  46. #46
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    Default Re: De-rating conductor

    You are looking at the ceiling in the living room which is the bottom of the second floor. It will have sheet rock and no insulation. There will be no venting of the cavity.
    I sent a link to this post and my client has read it. He is quite impressed with you guy's and myself for following up on issues like this. You guy's are the best.

    Thanks
    Mike

    I tried the 640 Jerry and it is to large. The 320 is way to small :-)
    That was my complaint, why not choose what most picture software uses.

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