310.15(B)(2) add Exception 6.

[hurk27]

This might follow Charlie's statement on the reason's we might wan't to make a proposal.
From another thread by Charlie: A lot of proposals are generated by individuals who are trying to get relief from a particular inspector or group of inspectors. So very true. But sometimes there are some unnecessary codes that conflict with other building codes that can make an installation more complicated than it needs to be.
And this one it has been a thorn sometimes with allot of inspectors and contractors. as we have seen post here already.


1.) NEC Section/Paragraph: 310.15(B)(2) add Exception 6.


2.) Proposal Recommends: [new text]
(Exception No. 6: derating factors shall not apply to cables ran in bored holes, or cut notches in floor joist or interior walls in residential dwellings where it meets

(a) Where these cables are run in bored holes in a wall, Floor, or ceiling space,where the ambient temperature will not exceed 40 deg. C. in normal use.
(b) Where these cables are run in any floor, wall or ceiling space with a high ambient temperature, The derating require in 310.15(B)(2) shall be followed.

4.) Substantiation: Where there is cables ran in bored holes in joist with spacing between each joist, the maximum load on these cables, will most likely never be used. the temperature of these cables would never run beyond the safely rated temperature of the cable. As the code is now it requires multiple holes to be bored in floor joist to accommodate the circuit runs and most building regulations limit the amount of these holes that can be safely bored into floor joist.

[charlie]

I like the concept and have made some suggested changes. We are ready for more comments and tweaking. :D

1.) NEC Section/Paragraph: 310.15(B)(2) add Exception 6.

2.) Proposal Recommends: [new text]

Exception No. 6: derating factors shall not apply to cables ran in bored holes, or cut notches in joists or interior walls in dwellings under the following conditions:

(1) Where these cables are run in bored holes in a wall, floor, or ceiling space, and where the ambient temperature will not exceed 30°C in normal use.

(2) Not more than 10 current carrying conductors are included in the bundle and are not larger that No. 12 Cu. or No. 10 Al.

4.) Substantiation: Where there are cables run in bored holes in joists with spacing between each joist, the maximum load on these cables, will most likely never be used because of the load profiles in dwelling units. The temperature rise of these cables is minimal under these conditions. By limiting this exception to 15 and 20 ampere circuits, the range, dryer, electric furnace, etc. are excluded and the likelihood of more than one or two heavily loaded circuits are eliminated.

The code now requires multiple holes to be bored in floor joists to accommodate the runs and building regulations limit the amount of these holes that can be safely bored into floor joist. This places an undue burden on the electrician to find exit routing from panelboards. This proposal will provide some relief from the stringent requirements.

[websparky]

Wayne,

I'm not sure I would agree with the need for a change. Here is why:

NM is 60C
NM 12AWG = 30A @ 90C * 70% = 21A


9 current carrying = 70% Derating
That means you can install
9 - 12/2 NM bundled = 21A
or
4 - 12/3 NM bundled =21A

If you are installing more than this in one hole or bunched together in the "stackers" you are not installing them properly in the first place!

I get to see more than 1400 residential installs per year. On occasion I find too many NM's "bundled" or "stacked". Usually it is the result of a new installer and an unusually difficult lay-out. The electricians up here are pretty good at planning a job and pretty creative with their lay-outs. So far only 2 red tags for overloading the "stackers". Not bad!

[roger]

Hello Dave, actually 9 12/2 NM cables would be 18 current carrying conductors.

Editted for spelling (carring verses carrying :( )

Roger

[ November 25, 2004, 01:39 PM: Message edited by: roger ]

[hurk27]

Charlie I was just thinking: If the service is a 100 amp or even a 200 amp it would be very hard to have enough current on these current carrying conductors with out over loading the service and tripping the main wouldn't it? 10 20 amp circuits would trip a 100 amp and would be very close to tripping a 200 if there were any other loads. so if this is true then why should there be any limit as the service main would keep these circuits limited wouldn't it?

Edited because I just relized that were talking about 120 volt circuits and the service could have 10 20 amp circuits on each leg and it would still be only 100 amps. Oh Dah! :o

[ November 27, 2004, 01:09 AM: Message edited by: hurk27 ]

[websparky]

Hello Roger,

Humm.......I didn't think we had to count 'em?

(4) Neutral Conductor.
(a) A neutral conductor that carries only the unbalanced current from other conductors of the same circuit shall not be required to be counted when applying the provisions of 310.15(B)(2)(a).

[hurk27]

Dave that would be true for the 12/3's but the 12/2's the neutral would have just as much current on them as the hot. Look at your original post. :D

[charlie]

Gentlemen, the reason that I believe this proposal has merit is the way residential circuits are loaded. If I bundled all the 15 and 20 ampere circuits in my home together, I would have a large bundle and not use but three or four circuits at a time. I get up and will use the bathroom circuit and kitchen circuit (gotta have coffee), I'll have a few lights on and then the garage door opener. The water heater circuit is #10 so it would not be included.

Now go through each part of your day in the same manner. The heavy load will be at dinner (trust me). The SA circuits will be used along with the kitchen and eating area lights. Lets do the laundry (can't count the 30A dryer circuit or the 30A WH circuit) and run the dishwasher. We are hitting 2 SA, 1 DW, 1 washer, and misc. lights. Where is the overloaded bundle?

I wonder if this needs to be included in the substantiation? :D

[websparky]

Wayne,

OK.. even if we count them that way, I still am not sure a change is needed.

If as you and Charlie are in agreement about the need, please also consider the effects of the cables when run in wall cavities or ceiling joist spaces that contain insulation. Their normal heat dissipation ability is considerably reduced.

Maybe something like this should be added:
394.12 Uses Not Permitted.(5) Hollow spaces of walls, ceilings, and attics where such spaces are insulated by loose, rolled, or foamed-in-place insulating material that envelops the conductors.

[ November 27, 2004, 12:18 PM: Message edited by: websparky ]

[hurk27]

Dave that was covered in the exception already look at the first requirement it has to meet

(1)Where these cables are run in bored holes in a wall, floor, or ceiling space, and where the ambient temperature will not exceed 30°C in normal use.

I'm not an engineer and thought 40oC would be sufficient but Charlie who would know dropped it to 30oC

Ok Charlie how did you make that degree mark? It's not on my keyboard :(

[physis]

Wayne, I just saved it to a notepad file and now I can copy it from there. °

180°

I think I'll start collecting characters like this. :cool:

[hurk27]

You know Sam I didn't even noticed that when I copied it from the other post that it also copied the degree character too. 30°C Cool Thank's :cool:

[charlie]

I'll give you a list of some that I like to use. Hold down the ALT key while you type in the whole number on you key pad.

0169 © Copyright
0174 ® Registered
0176 ° Degree
0177 ± Plus or Minus
0178 ² Superscript 2
0179 ³ Superscript 3
0185 ¹ Superscript 1
0188 ¼ 1/4
0189 ½ 1/2
0190 ¾ 3/4
0216 Ø Phase mark

Use your notepad and you can see what other symbols can be made.

[iwire]

I can't make it work :(

[hurk27]

This is so cool Charlie I had no Idea.

ؾ©®æoo+_¼¼¸p&¤®¯D§¦¥¤£

[hurk27]

Bob hold down your Alt button then type the 074 then let go of the Alt button and it appears. also if your using you number key pad make sure numbers lock is on.

[iwire]

I will give it another try.

Nope nothing from the numbers at the top or from the keypad. :confused:

Maybe a setting has to be changed? :confused:

[hurk27]

What kind of computer is it not an Apple is it?
«““�žê{宯²©ˆ‰Š‹€�~‡|}†‡ˆ‰Š‹çåÒXhô-_GBëî¼O_ÜjJ+_x+++o++ÄA_§}œš

Mine is a PC and it works all to good. Now I have somthing else to check out. :D

[roger]

}o{0Ò0-@‡N0-{棺_²

Thats neat

Roger

[iwire]

Originally posted by hurk27:
What kind of computer is it not an Apple is it?No it is an IBM type....do we still describe it that way or do we simply say a Windows machine? :p

[iwire]

Originally posted by roger:
}o{0Ò0-@‡N0-{棺_²

Thats neat

Roger Show off! :D

[roger]

;)

Roger

[physis]

What am I gonna do with this stuff?

• ◘ ○ ♦ ♣ ♠ ☺ ☻ ♥

Edit: I get it, you have to use the characters number.

¢ £ ¥ ╜ ƒ á

These are characters 155 thru 160.

[ November 28, 2004, 01:43 PM: Message edited by: physis ]

[physis]

On the "StartMenu" All programs/Accessories/System Tools/Character Map

Character Map is a program, check it out. :)

[hurk27]

ÛÜÑ_°äåæ‰AAAAAŽA8@rsvwxØ×ýúÒÒêçåãÖÕÔÒÓÌËÊÉÌbceFEIN O
éêèçæäãâáàíîðóóóóòñõ
õ*¡£¤¥¦§¨©ª«¬*®¯
BA@CDEFGHIJKLMNOP,*ÊÎÑÚÛÜÞß®©¤eVEN COOLER :D

[physis]

Wayne, you must be as easily amused as I am. :D

Edit: What's cool is I can do this now ω2πR² Except that's a poor excuse for Pi.

[ November 28, 2004, 03:59 PM: Message edited by: physis ]

[iwire]

أوروبا, برمجيات الحاسوب + انترنيت :
تصبح عالميا مع يونيكود
تسجّل الآن لحضور المؤتمر الدولي العاشر ليونيكود, الذي سيعقد في 10-12 آذار 1997 بمدينة ماينتس, ألمانيا. وسيجمع المؤتمر بين خبراء من كافة قطاعات الصناعة على الشبكة العالمية انترنيت ويونيكود, حيث ستتم, على الصعيدين الدولي والمحلي على حد سواء مناقشة سبل استخدام يونكود في النظم القائمة وفيما يخص التطبيقات الحاسوبية, الخطوط, تصميم النصوص والحوسبة متعددة اللغات.
عندما يريد العالم أن يتكلّم, فهو يتحدّث بلغة يونيكود.

[charlie]

If you are using my list, don't forget the leading 0. It looks like I have unleashed a monster here. :D

[charlie]

BOB!!! What did you do! :D :D

[physis]

Bob, are you calling me names?

[iwire]

Originally posted by physis:
Bob, are you calling me names? I hope not! :o

[iwire]

Originally posted by charlie:
Bob, did you get your's working? Yes, it turns out I need Number Lock © on and I must use the number keypad.

I wish it took me ½ the time to figure it out. ;)

[roger]

Originally posted by iwire:
Originally posted by physis:
Bob, are you calling me names? I hope not! :o I know what it says, but I'm not saying. :D


Just Kidding.

Roger

[physis]

Do you really think I have any idea what that says? :D Of course not, it's Roger I'm worried about. :D

[hurk27]

By Bob: Do you really think I have any idea what that says? If you did I would start worrying. ;)

[hurk27]

Ok Charlie (now that we got the new toys out of the way) what's the next step? Or should I be asking Bob A.?

[electricmanscott]

For some real fun type 55378008 on a calculator and read it upside down! :D

[charlie]

Bob Alexander is the moderator for this part of the forum but, in my opinion, you have what is required to put together a good proposal with the proper substantiation. If you don't feel comfortable yet, you may want to re-post your finished product for further critique. :D

[hurk27]

Thanks I'll print the form and fill it out then post the results.

Wouldn't it be nice to have a practice form here that we could fill out to know we were doing it correct? It wouldn't take much to change a PDF to a HTML form.

[charlie]

Actually, it would. PDF forms are not convertible to other forms such as Word or HTML without redoing the form. However, I have a form in Word already for last cycle but I am not so sure that we need the whole form. The most salient parts are what Bob is asking for, the rest is easy. :D

[iwire]

Originally posted by charlie:
I like the concept and have made some suggested changes. We are ready for more comments and tweaking. :D I also think this is a great idea, and would like to make few comments.

First is the following text what will be submitted?

1.) NEC Section/Paragraph: 310.15(B)(2) add Exception 6.

2.) Proposal Recommends: [new text]

Exception No. 6: derating factors shall not apply to cables ran in bored holes, or cut notches in joists or interior walls in dwellings under the following conditions:

(1) Where these cables are run in bored holes in a wall, floor, or ceiling space, and where the ambient temperature will not exceed 30°C in normal use.

(2) Not more than 10 current carrying conductors are included in the bundle and are not larger that No. 12 Cu. or No. 10 Al.

4.) Substantiation: Where there are cables run in bored holes in joists with spacing between each joist, the maximum load on these cables, will most likely never be used because of the load profiles in dwelling units. The temperature rise of these cables is minimal under these conditions. By limiting this exception to 15 and 20 ampere circuits, the range, dryer, electric furnace, etc. are excluded and the likelihood of more than one or two heavily loaded circuits are eliminated.

The code now requires multiple holes to be bored in floor joists to accommodate the runs and building regulations limit the amount of these holes that can be safely bored into floor joist. This places an undue burden on the electrician to find exit routing from panelboards. This proposal will provide some relief from the stringent requirements.Why did "and where the ambient temperature will not exceed 30°C in normal use." get added?

I ask because IMO this proposed exception is very similar to an exception near and dear to me and there is no mention of ambient temps in it.


310.15(B)(2)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:

(a)Each cable has not more than three current-carrying conductors.

(b)The conductors are 12 AWG copper.

(c)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.I feel the proposal could simply ask for the addition of NM and tweaking to this existing exception.

IMO 310.15(B)(2) is already a convoluted article, the addition of yet another exception will exasperate that.

Here is what I imagine, my changes in bold.

310.15(B)(2)Exception No. 5: Adjustment factors shall not apply to Type AC cable or to Type MC cable without an overall outer jacket or to Type NM or UF cable under the following conditions:

(a)Each cable has not more than three current-carrying conductors.

(b)The conductors are 12 AWG or 14 AWG copper.

(c)Not more than 20 current-carrying conductors are bundled, stacked, run in bored holes in a wall, floor, or ceiling space 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.

Substantiation: Where there are cables run in bored holes in joists, studs, etc snip, the maximum load on these cables, will most likely never be used because of the load profiles of 15 and 20 amp circuits snip. The temperature rise of these cables is minimal under these conditions. By limiting this exception to 15 and 20 ampere circuits, the range, dryer, electric furnace, etc. are excluded and the likelihood of more than one or two heavily loaded circuits are eliminated.

The code now requires multiple holes to be bored in floor joists to accommodate the runs and building regulations limit the amount of these holes that can be safely bored into floor joist. This places an undue burden on the electrician to find exit routing from panelboards. This proposal will provide some relief from the stringent requirements.I do wonder about my adding 14 AWG to the existing MC requirements?

This is not so easy. :D

What do you all think?

Wayne I hope you understand that I am not criticizing your efforts, I think you have a great idea.

Good luck to you with this.

Bob

[hurk27]

By Bob: Why did "and where the ambient temperature will not exceed 30°C in normal use." get added?
I did say 40°C but I did have some concern as did Dave did with bundling in outside walls or attic spaces where the cables could be subject to much higher temp's. And Charlie lowered it to 30°C which seem's a little low but he's the engineer.

I do have a question for Charlie is why the 10 conductor limit as the code already allows for 9 current carrying conductors and I was thinking more to what Bob has in the requirement for AC cables? 20 I don't see this need if we are to only gain one current carrying conductor do you?

[ December 01, 2004, 07:42 PM: Message edited by: hurk27 ]

[hurk27]

By Bob: Wayne I hope you understand that I am not criticizing your efforts, I think you have a great idea Never Bob. I'm here to learn too ;)

[don_resqcapt19]

Bob,
There may have to be some reference to the new part of 334.80 in the 2005 code.
Don

[hurk27]

Ok how's this with my additions to Bob's in bold:

310.15(B)(2)Exception No. 5: Adjustment factors shall not apply to Type AC cable or to Type MC cable without an overall outer jacket or to Type NM or UF cable installed in a dwelling under the following conditions:

(a)Each cable has not more than three current-carrying conductors.

(b)The conductors are 12 AWG or 14 AWG copper.

(c)Not more than 20 current-carrying conductors are bundled, stacked, run in bored holes in a wall, floor, or ceiling space 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.

This Exception shall not apply where more than two NM cables containing two or more current carrying conductors are bundled together and pass through wood framing that is to be fire- or draft stopped using thermal insulation or sealing foam, as required in 334.80

Substantiation: Where there are cables run in bored holes in joists, studs, etc snip, the maximum load on these cables, will most likely never be used because of the load profiles of 15 and 20 amp circuits snip. The temperature rise of these cables is minimal under these conditions. By limiting this exception to 15 and 20 ampere circuits, the range, dryer, electric furnace, etc. are excluded and the likelihood of more than one or two heavily loaded circuits are eliminated.

The code now requires multiple holes to be bored in floor joists to accommodate the runs and building regulations limit the amount of these holes that can be safely bored into floor joist. This places an undue burden on the electrician to find exit routing from panelboards. This proposal will provide some relief from the stringent requirements.

[ December 04, 2004, 02:56 AM: Message edited by: hurk27 ]

[charlie]

Sorry, I have been tied up for a while so I will only address the last post. :)

310.15(B)(2)Exception No. 5: Adjustment factors shall not apply to Type AC cable or to Type MC cable without an overall outer jacket or to Type NM or UF cable installed in a dwelling under the following conditions:

It sounds like they all have to be installed in dwellings. I am not sure how to tweak that or if it really needs to be tweaked.

(b)The conductors are 12 AWG or 14 AWG copper.

Now you are changing the rules for Type MC cable with no substantiation for doing so.

(c)Not more than 20 current-carrying conductors are bundled, stacked, run in bored holes in a wall, floor, or ceiling space or supported on “bridle rings.”

Nothing is said about insulation in the walls, floor or ceiling space and this applies to MC cable. The paragraph you are adding would only apply to Type NM cables and not to Type UF or MC cables.

I really think you need to make a separate exception for Type NM and UF cables. :D

[physis]

This is a really big thread and I haven't read more than half of it. But I was thinking that this proposal could have an undesireable side effect.

You guys sometimes use an odd kind of logic in interpretting codes. Usually associated with exeptions. When something is specificly allowed by exeption it's taken as implied that outside of that exeption the opposite must be true.

Is there a danger that the nonexistant need for derating where it's not required will acctually be reenforced outside of the exeption?

[charlie]

Sam, there is always the danger of misinterpretation. However, each item a person is trying to get by with or the AHJ is trying to enforce must be backed up by the words of the Code, not by inference. You will always say that something is not in compliance with the Code, not that the Code infers that something is not in compliance. :D

[physis]

Well Charlie, It's interesting you put it that way because that also applies to proposed change.

:)

Edit: I mean the proposed exception is to eliminate a misinterpretaion caused by inference. Isn't it?

[ December 05, 2004, 06:44 PM: Message edited by: physis ]

[charlie]

Sam, proposals are also made to correct what AHJs are enforcing if you do not agree with them. Sometimes the panel will turn a proposal down on the grounds that it already says what you want it to do. In those cases, the panel will write a statement that serves as an official interpretation. In other cases, the panel may rewrite the rule to make it more clear. This is part of the reason that the Code is so big and is not getting any smaller. :D

[physis]

Good morning Charlie,

I'm just jumping up and down on it a little to see how it holds up. :)

[charlie]

My 2005 Edition is hardbound so it will hold up pretty good. ;)

[rbalex]

Originally posted by charlie:
I'll give you a list of some that I like to use. Hold down the ALT key while you type in the whole number on you key pad.

0169 © Copyright
0174 ® Registered
0176 ° Degree
0177 ± Plus or Minus
0178 ² Superscript 2
0179 ³ Superscript 3
0185 ¹ Superscript 1
0188 ¼ 1/4
0189 ½ 1/2
0190 ¾ 3/4
0216 Ø Phase mark

Use your notepad and you can see what other symbols can be made. This would be great FAQ stuff; if only we had some way to create "strikeout" text.

BTW: Wayne, are we at a point where you feel you have your "final" version? If yes, I'll close out this thread. If not, we can continue as long as you want. The goal is to help the submitter create a strong Proposal.

[hurk27]

Sorry for not getting back right away as I was under the weather. (Rain, cold, rain, cold yuk!)

I Wasn't sure if this is what I should submit. Or Bob's version as Charlie think's it would be better to keep NM/UF separate from the AC cable.

But I would like input as to why it is needed to keep the amount of conductors to only 10 as the code is now we are allowed 9 current caring conductors with the derating from table 310.16 using the allowed 90°C column now? Adding 1 conductor would not seem to gain enough leeway to require the change?

1.) NEC Section/Paragraph: 310.15(B)(2) add Exception 6.

2.) Proposal Recommends: [new text]

Exception No. 6: derating factors shall not apply to cables ran in bored holes, or cut notches in joists or interior walls in dwellings under the following conditions:

(1) Where these cables are run in bored holes in a wall, floor, or ceiling space, and where the ambient temperature will not exceed 30°C in normal use.

(2) Not more than 10 current carrying conductors are included in the bundle and are not larger that No. 12 Cu. or No. 10 Al.

4.) : Where there are cables run in bored holes in joists with spacing between each joist, the maximum load on these cables, will most likely never be used because of the load profiles in dwelling units. The temperature rise of these cables is minimal under these conditions. By limiting this exception to 15 and 20 ampere circuits, the range, dryer, electric furnace, etc. are excluded and the likelihood of more than one or two heavily loaded circuits are eliminated.

The code now requires multiple holes to be bored in floor joists to accommodate the runs and building regulations limit the amount of these holes that can be safely bored into floor joist. This places an undue burden on the electrician to find exit routing from panelboards. This proposal will provide some relief from the stringent requirements. Another substantiation that could be added:
Is that the fact that in commercial environments 15 and 20 amp. circuits are ran for specific planed loads, but in a residential environment 15 and 20 amp. circuits are ran for convenience and most likly will never be loaded to the max.

Ok any more thought's?

[ December 06, 2004, 08:32 PM: Message edited by: hurk27 ]

[charlie]

I can see the following:

(2) Conductors included in the bundle are not larger that No. 12 Cu. or No. 10 Al.

This could be argued that the dwelling unit load is so diverse and that those circuits are almost totally for convenience; therefore, the need for derating is not required as circuits will be used minimally and in small groups. The heaviest loaded circuits would likely be one or two small appliance branch circuits, a bathroom receptacle circuit, and a laundry circuit. Those circuits, mixed in with the other circuits, would not require derating.

[hurk27]

Ok one last time for final tweeking. :p

1.) NEC Section/Paragraph: 310.15(B)(2) add Exception 6.

2.) Proposal Recommends: [new text]

Exception No. 6: derating factors shall not apply to cables ran in bored holes, or cut notches in joists or interior walls in dwellings under the following conditions:

(1) Where these cables are run in bored holes in a wall, floor, or ceiling space, and where the ambient temperature will not exceed 30°C in normal use.

(2) Are not larger that No. 12 Cu. or No. 10 Al.

4.) : Where there are cables run in bored holes in joists with spacing between each joist, the maximum load on these cables, will most likely never be used because of the load profiles in dwelling units. The temperature rise of these cables is minimal under these conditions. By limiting this exception to 15 and 20 ampere circuits, the range, dryer, electric furnace, etc. are excluded and the likelihood of more than one or two heavily loaded circuits are eliminated.

The code now requires multiple holes to be bored in floor joists to accommodate the runs and building regulations limit the amount of these holes that can be safely bored into floor joist. This places an undue burden on the electrician to find exit routing from panelboards. This proposal will provide some relief from the stringent requirements.
And that the dwelling unit load is so diverse and that those circuits are almost totally for convenience; therefore, the need for derating is not required as circuits will be used minimally and in small groups. The heaviest loaded circuits would likely be one or two small appliance branch circuits, a bathroom receptacle circuit, and a laundry circuit. Those circuits, mixed in with the other circuits, would not require derating. Charlie is this what you envisioned?

[charlie]

Yes but after seeing it in total, I wasn't seeing the sun when I put the second statement together. It should read:

(1) Where these cables are run in bored holes in a wall, floor, or ceiling space, and where the ambient temperature will not exceed 30°C in normal use and;

(2) where these cables are not larger that No. 12 Cu. or No. 10 Al.

[hurk27]

Ok how's this:

1.) NEC Section/Paragraph: 310.15(B)(2) add Exception 6.

2.) Proposal Recommends: [new text]

Exception No. 6: derating factors shall not apply to cables run in bored holes, or cut notches in joists or interior walls in dwellings under the following conditions:

(1) Where these cables are run in bored holes in a wall, floor, or ceiling space, and where the ambient temperature will not exceed 30°C in normal use and.

(2) Where these cables Are not larger than No. 12 Cu. or No. 10 Al.

4.) : Where there are cables run in bored holes in joists with spacing between each joist, the maximum load on these cables, will most likely never be used because of the load profiles in dwelling units. The temperature rise of these cables is minimal under these conditions. By limiting this exception to 15 and 20 ampere circuits, the range, dryer, electric furnace, etc. are excluded and the likelihood of more than one or two heavily loaded circuits are eliminated.

The code now requires multiple holes to be bored in floor joists to accommodate the runs and building regulations limit the amount of these holes that can be safely bored into floor joist. This places an undue burden on the electrician to find exit routing from panelboards. This proposal will provide some relief from the stringent requirements.
And that the dwelling unit load is so diverse and that those circuits are almost totally for convenience; therefore, the need for derating is not required as circuits will be used minimally and in small groups. The heaviest loaded circuits would likely be one or two small appliance branch circuits, a bathroom receptacle circuit, and a laundry circuit. Those circuits, mixed in with the other circuits, would not require derating.

[charlie]

I feel like I am really belaboring the process. What do you think about this?

Exception No. 6: derating factors shall not apply to cables run in bored holes, or cut notches in joists or interior walls in dwellings under all of the following conditions:

(1) Where these cables are installed in wall, floor, or ceiling spaces that have no insulating material

(2) Where the ambient temperature will not exceed 30°C in normal use

(3) Where these cables are not larger than No. 12 Cu. or No. 10 Al.

Sorry Wayne, every time I look at this I see something else. :(

[George Stolz]

Thoughts from a small mind: I really like this. Many panels are installed in garage walls and this could provide protection for them, if the insulation hang-up was removed. My other thought was that the cables' individual articles already denote acceptable installation methods, so it might be duplicative. And I like to pick things apart and try them different ways grammatically, my apologies. It's probably OCD. Here is a different way of wording it... :)

1.) NEC Section/Paragraph: 310.15(B)(2) add Exception 6.

2.) Proposal Recommends: [new text]

Exception No. 6: derating factors shall not apply to cables installed in joists or interior walls in dwelling units under all of the following conditions:

(1) Where these cables are installed in wall, floor, or ceiling spaces where the ambient temperature will not exceed 30°C in normal use

(3) Where these cables are not larger than No. 12 Cu. or No. 10 Al

4.) : Where there are cables run in bored holes in joists with spacing between each joist, the maximum load on these cables will most likely never be used because of the load profiles in dwelling units. The temperature rise of these cables is minimal under these conditions. By limiting this exception to 15 and 20 ampere circuits, the range, dryer, electric furnace, etc. are excluded and the likelihood of more than one or two heavily loaded circuits are eliminated.

The code now requires multiple holes to be bored in floor joists to accommodate the runs. Building regulations limit the amount of these holes that can be safely bored into floor joists. This places an undue burden on the electrician to find exit routing from panelboards. This proposal will provide some relief from the stringent requirements.

In addition the dwelling unit load is so diverse that those circuits are almost totally for convenience; therefore, derating becomes redundant as circuits will be used minimally and in separate locations. The heaviest loaded circuits would likely be one or two small appliance branch circuits, a bathroom receptacle circuit, and a laundry circuit. This mix of moderately used and unused circuits would not require derating.

[hurk27]

I feel like I am really belaboring the process. What do you think about this?

Hey Charlie other than boring the other people here who cars? Besides that, we have a year. :o

(2) where these cables are not larger that No. 12 Cu. or No. 10 Al. I just changed it the post before yours. :o It must have been that "copy and paste thing" LOL :o
Should we try to incorporate it back in?

This Exception shall not apply where more than two NM cables containing two or more current carrying conductors are bundled together and pass through wood framing that is to be fire- or draft stopped using thermal insulation or sealing foam, as required in 334.80 Or would there be a better way of wording this?
Boy this isn't easy, But a lot of fun and a good learning experience. :D

Sorry Wayne, every time I look at this I see something else. Keep seeing, Keep seeing LOL

P.S. Thank's Charlie for all the help. :D
You too Bob. :D And all the rest.

[charlie]

I will have to give that some thought. I think it is important to deal with open (not insulated) spaces if we are going to bundle the whole world together (OK, just the 15 and 20 ampere world). :D

[mulllet]

IT only works if I use the number keys on the right side of the keyboard not the ones up top.
© ® ° Cool.

[physis]

Well, since this topic emerged on my monitor again.

Have you submitted a proposal yet Wayne?

[hurk27]

Not yet as I have been real busy lately But maybe Charlie has some new ideas to throw out here?
I just don't see the bundling issue that allot of inspectors do. and with a code change will stop some of the rules like that was posted in another thread saying that some areas only allow one cable to a hole. :roll:

[charlie]

Sam, I would wait until the first of September to do any submittals. This gives plenty of time to let them move around in your mind. Also, more general discussion will have been done in the forum that may influence your proposal. The deadline is not until November 4th @ 5:00 PM EST so September up to mid-October is a good time to send in the proposals. :D

[physis]

That's a good point Charlie. I presume you guys wont start on them until "Proposal Season" anyhow.

[heco]

Well I be durn........that is Awsummmm

[George Stolz]

Originally posted by hurk27:
[QB]the dwelling unit load is so diverse and that those circuits are almost totally for convenience; therefore, the need for derating is not required as circuits will be used minimally and in small groups. The heaviest loaded circuits would likely be one or two small appliance branch circuits, a bathroom receptacle circuit, and a laundry circuit. Those circuits, mixed in with the other circuits, would not require derating.Given this good point, would it make sense to create a different section for dwelling units, and have the existing section deal with "other than dwelling units"? Might add clarity.

Then this could be knocked down to:
This Exception shall not apply to NM cables bundled as described in 334.80

[slk]

I am betting that the code panel will disaprove this change due to the FPN to table 310.15(B)(2)(a). The FPN allows for load diversity to increase the derating capacity to 70% for up to 24 conductors (etc. per the table). Load diversity is present nowhere if not in a residence. I have used this table with approval (inspector not engineer) in my neck of the woods for residential applications, never tried for commercial...

[charlie]

SLK, read the substantiation on the first post in this thread. I really do think it has a fighting chance. :D

[physis]

Do you the CMP or Wayne Charlie?

[slk]

I am not an engineer, nor do I play one on TV, but it seems to me that the original proposal (first post) wants to eliminate derating factors entirely in the situations described due to load diversity. I am saying that these situations have already been looked into by the code panel and they have come up with the limitations that the load diversity table provides. For this reason I think the proposal may be doomed to failure.

Using the load diversity table that I mentioned, you can run 12 12/2 NMB cables in the same bundle for longer than 24 inches and still maintain a 20 amp breaker on the conductors. You could run 21 14/2 NMB cables in the same bundle for more than 24 inches and still maintain a 15 amp breaker on the conductors. Do these limitations need to be exceeded very often in the field?

I think I understand that we are trying to eliminate the interpretation by some inspectors of bored holes fitting into the definition of bundling, thereby requiring derating. I just see a possibility of the code panel rejecting this approach due to the load diversity table already being in the code (the load diversity issue has already been looked into with the previously mentioned limitations).

Please note that I am not intending to shut down anyone's good idea, just trying to contribute to the thread in a way that I haven't seen anyone mention yet. I also could be missing something; I was perfect once, and then I was born...

[physis]

If I remember right the impetus behind the proposal was inspectors calling cables ran through bored holes bundled.

[George Stolz]

Load diversity is pretty involved stuff. This proposal would provide a clearer means of relief from the problem, IMO.

[hurk27]

Time to get this rolling again, as I'll be leaving for Hot Springs Ak. next weekend for Western Section then off to Florida for a couple weeks:
Any more Idea's?




1.) NEC Section/Paragraph: 310.15(B)(2) add Exception 6.

2.) Proposal Recommends: [new text]

Exception No. 6: derating factors shall not apply to cables run in bored holes, or cut notches in joists or interior walls in dwellings under the following conditions:

(1) Where these cables are run in bored holes in a wall, floor, or ceiling space, and where the ambient temperature will not exceed 30°C in normal use and.

(2)Where the ambient temperature will not exceed 30°C in normal use

(3) Where these cables Are not larger than No. 12 Cu. or No. 10 Al.

(4) This Exception shall not apply where more than two NM cables containing two or more current carrying conductors are bundled together and pass through wood framing that is to be fire- or draft stopped using thermal insulation or sealing foam, as required in 334.80

4. Statement of Problem and Substantiation for Proposal.
Where there are cables run in bored holes in joists with spacing between each joist, the maximum load on these cables, will most likely never be used because of the load profiles in dwelling units. The temperature rise of these cables is minimal under these conditions. By limiting this exception to 15 and 20 ampere circuits, the range, dryer, electric furnace, etc. are excluded and the likelihood of more than one or two heavily loaded circuits are eliminated.

The code now requires multiple holes to be bored in floor joists to accommodate the runs and building regulations limit the amount of these holes that can be safely bored into floor joist. This places an undue burden on the electrician to find exit routing from panelboards. This proposal will provide some relief from the stringent requirements.
And that the dwelling unit load is so diverse and that those circuits are almost totally for convenience; therefore, the need for derating is not required as circuits will be used minimally and in small groups. The heaviest loaded circuits would likely be one or two small appliance branch circuits, a bathroom receptacle circuit, and a laundry circuit. Those circuits, mixed in with the other circuits, would not require derating.



[ September 17, 2005, 03:33 PM: Message edited by: hurk27 ]