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Thread: Romex cable

  1. #1
    mathew stouffer's Avatar
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    Default Romex cable

    Do you right this up? There are more than four cables bundled together at the passage throught the joist and the rest of the installation is messy. I came through about ten minutes after the county inspector and is didn't bother him.

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    Default Re: Romex cable

    I would forget about the 4 through the joist ... it's THE REST of that mess which needs attention. There is no 'maintaining spacing' going on there, and that is addressed the same as "bundling", with the same derating factors applied.

    The county inspector may not have had a problem with it, but that very issue is addressed frequently in the IAEI (International Association of Electrical Inspectors) News trying to get all electrical inspectors attention on this issue.

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  3. #3
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    Default Re: Romex cable

    Thanks Jerry. What is the wording you most often use.


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    Default Re: Romex cable

    concerning pic #2
    E3305.3 Dedicated panelboard space. The space equal to the
    width and depth of the panelboard and extending from the floor
    to a height of 6 feet (1829 mm) above the panelboard, or to the
    structural ceiling, whichever is lower, shall be dedicated to the
    electrical installation. Piping, ducts, leak protection apparatus
    and other equipment foreign to the electrical installation shall
    not be installed in such dedicated space. The area above the dedi-
    cated space shall be permitted to contain foreign systems, pro-
    vided that protection is installed to avoid damage to the electrical
    equipment from condensation, leaks and breaks in such foreign
    systems (see Figure E3305.1).

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  5. #5
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    Default Re: Romex cable

    Victor,
    Good call, I totally missed that one


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    Default Re: Romex cable

    Quote Originally Posted by mathew stouffer View Post
    What is the wording you most often use.
    From the NEC. (underlining is mine)
    - 310.15 Ampacities for Conductors Rated 02000 Volts.
    - - (B) Tables. Ampacities for conductors rated 0 to 2000 volts shall be as specified in the Allowable Ampacity Table 310.16 through Table 310.19, and Ampacity Table 310.20 and Table 310.21 as modified by (B)(1) through (B)(6).
    - - - (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.
    (there are a bunch of exceptions, however none apply, so I did not list them)

    I always used the code language in my report, i.e, the code states: "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 ", thus, I would use "without maintaining spacing" and "for 24" or greater" - that covers the two main aspects of it.

    When the electrician comes back and says 'Those are not "bundled", "bundling" is when they are strapped together and those are not strapped together." - which is actually only his definition of bundling, but it is not applicable as you stated "without maintaining spacing" and ... by golly, that is in the code, word-for-word.

    Meaning he is standing in deep $hit because he just admitted he not only did not read what you reported on (obviously he did not read your report where you stated "without maintaining spacing"), but he also does not know the code, which you gladly direct him to, because it contains your exact wording ... word-for-word.

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  7. #7
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    Default Re: Romex cable

    Sloppy work, no doubt.

    Sewer pipe in dedicated panel space, too many cables in each clamp entering the panel, and needs to be secured within 12" of the panel.

    But I don't see an issue with maintaining the spacing. You can see air between most of those cables, they are not touching for more than 24". Also, you can have 4 #12 cables completely bundled and derated and it is still good for a 20 amp breaker.


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    Default Re: Romex cable

    Quote Originally Posted by Tim Voss View Post
    But I don't see an issue with maintaining the spacing. You can see air between most of those cables, they are not touching for more than 24". Also, you can have 4 #12 cables completely bundled and derated and it is still good for a 20 amp breaker.

    As best I can see in the photo, the left 'bunch' at the panel starts out as one 'bunch' of 11-12 cables, albeit for less than 24", probably about 12"+/-. Thus, we only need to go up another 12", and in this case there are 2 'bunches' of cables, the left having 4 2-conductor cables for 8 conductors and the right having 7-8 2-conductor cables for 14-16 conductors ... for well over 24".

    Now let's address "derating", what it is based on, and how it is supposed to be done.

    Let us presume 90 degree C rated insulation, which means that #12 NM-B has a theoretical ampacity of 30 amps before applying any derating. Remember, though, it must still be protected at 20 amps or less.

    30 amp rating before derating for ambient temperature (which is always the first derating applied).

    Let's presume that one or more of those goes up into the attic, which we will presume gets to 135 degrees F during the peak heat of the summer. Oh? You say it does not get that hot, it only gets to 125 degrees F? Okay, let us start there, 135 degrees just gets worse, so we will go with 'best case'.

    The 30 amp rating is derated to o.76 of the previous rating value, so 30 x 0.76 = 22.8 amps. Okie dokie, that still meets the rating for a 20 amp breaker.

    Now, though, the derated rated for ambient is 22.8 amps (and that is with an attic of only 125 degrees F).

    Now we apply the "lack of maintaining spacing" derating.

    The 'bunch' with 8 conductors gets derated as follows: 22.8 amp rating gets derated to 70% when there are 7-9 conductors together, or, 22.8 x 70% = 15.96 amps derated rating.

    The 'bunch' with 11-12 conductors gets derated as follows: 22.8 amp rating gets derated to 50% when there are 10-20 conductors together, or, 22.8 x 50% = 11.4 amps derated rating.

    And you want to put those on a 20 amp breaker?

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    Default Re: Romex cable

    Jerry;
    Some of those cables (blue) appear to be cat-5 networking cables. Does their proximity to the electrical conductors pose any concern ie: interference due to magnetic fields.
    Should they not be run separate from electrical conductors?

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    Default Re: Romex cable

    Victor,

    There is no requirement for it that I know of.

    However, yes, 'good workmanship' would include such - but 'good workmanship' is not present in those photos.

    As you pointed out in your previous post, that sewer line and those supply lines (that PEX) should not be run above the panel area. That is also an indicator of that lack of 'good workmanship'.

    Also, the ends of those TJI, aren't they supposed to be in hangers? What about at the bearing at that wall, squash blocks?

    Based on all those unused holes drilled through the top plate at that wall to the right, I suspect that the electrical panel was originally going to be installed there.

    Just wondering and thinking out loud here.

    By the way, I wonder what is on the other side of that wall, no insulation on the wall, and, what is above that area? No insulation on the underside of the 'floor' either. Wondering if this is 'in' the thermal envelope or if the thermal envelope is on the other side insulated wall?

    Last edited by Jerry Peck; 08-20-2008 at 05:23 PM.
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  11. #11
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    Default Re: Romex cable

    Looks like it's inside the thermal envelope, thus no temperature derating. The bunch on the right actually breaks into two groups of 3-4 cables. Also, within derating limits.

    I think sometimes we get too zealous about bundling, as a bunch of cables touching intermittently with space between them is not bundled and does not need derating.


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    Default Re: Romex cable

    Quote Originally Posted by Tim Voss View Post
    Looks like it's inside the thermal envelope, thus no temperature derating.
    Only if those circuits are "entirely" within the thermal envelope, any part of any circuit which goes into an attic space would require derating for ambient temperature of the attic (unless the attic was one of the newer sealed and insulated at the roof sheathing attics).

    The bunch on the right actually breaks into two groups of 3-4 cables. Also, within derating limits.
    That bunch on the right also has some which leave the bunch on the right and merge with the bunch on the left, for more than 24", and which would require derating.

    I think sometimes we get too zealous about bundling, as a bunch of cables touching intermittently with space between them is not bundled and does not need derating.
    I think sometimes we get too zealous in defending the status quo and poor workmanship, which is exactly why this issue comes up so often in the IAEI News. It ain't news, it is "old hat" stuff which has been around for a very long time. It's just that it has been ignored by people who think like you do, they think it is 'no big deal', but it is. That is why it is still (*still*) in the codes - it is not something new. Just the need to enforce it is something new.

    Those old fart electricians of days gone by either (or both) knew better and/or wanted their work to look nice and neat. The latter accomplished the former. When everything was in conduit it was all run with "spacing maintained", and even Knob and Tube was run with "spacing maintained", even most older NM cable installations were run with "spacing maintained".

    Now, though, it takes electrical contractors who care about their work, and electricians working for them who also care about their work - see the attached photos from recent municipal support inspections. *They done good.*, thus I had to take a photo of it and commend them on their work.

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    Default Re: Romex cable

    Matthew;
    Was this finished work? A phase inspection? Are the sparkys coming back to finish? Looks like it.
    Reason I ask is, it would make sense, if you caught them before they finished, for the sloppiness of the job.
    Maybe they'll neatin things up some.
    Which does not excuse the other obvious defects.

    If that is a finished product, then I say have at'em with every dam nit-pickin little thing you can find.
    Maybe then they'll fix the "Major stuff" (yeah right)

    "The AHJ said it was all good, and that's that"

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  14. #14
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    Default Re: Romex cable

    So what exactly does the NEC say is the minimum spacing that must be maintained?


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    Quote Originally Posted by Tim Voss View Post
    So what exactly does the NEC say is the minimum spacing that must be maintained?
    The best I've ever gotten out of anyone (and I've talked to many "experts" and "wire manufacturers" about this and the answer is - 110.3(B).

    See all those separate holes coming out the top of the panel enclosure for the NM cable clamps? See how far apart they are spaced?

    Yeah, "maintain that spacing and there should not be any problems", that what I've gotten from several sources.

    The wire manufacturers say 'Hmmmm ... no one has ever asked that before ... I guess as long as they are not touching anywhere and are separated at least by the thickness of the staples securing the NM cables in place.' Then, as a little more discussion, 'What would be better would be to maintain the spacing from where they come out of the boxes and panels, there should not be any problems with that, that is the spacing they maintain with conduit, so that will work, it has historically'.

    So, there is the answer: See the spacing between NM connectors? Maintain that spacing. All the way.

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  16. #16
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    Default Re: Romex cable

    Right, the NEC does not say what the minimum spacing is.

    The whole point of spacing is to dissipate heat, it doesn't have to look pretty. Tests have shown that if the cables are touching or bundled for 24" they will overheat, so the derating. If they are not touching, then air can circulate and cool the conductors.

    I don't see any cables in that picture that are in physical contact for 24" or more.


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    Quote Originally Posted by Tim Voss View Post
    Right, the NEC does not say what the minimum spacing is.
    As I said, the NEC DOES state what the minimum spacing is - in 110.3(B), which is specified by the manufacturers through the SPACING of their knock-outs for the NM cables.

    And, yes, the purpose is to (as you stated) "The whole point of spacing is to dissipate heat". As far as "it doesn't have to look pretty" - no one said it did have to look pretty.

    The cables need more than "If they are not touching" to allow for "air can circulate and cool the conductors".

    What is the spacing required for conduits? Which, by the way, are also mentioned in that same section - 310.15(B)(2)(b) More Than One Conduit, Tube, or Raceway. Spacing between conduits, tubing, or raceways shall be maintained.

    The same spacing as for NM cable - 'as provided for by the manufacturer' - which gets back to the same NEC CODE 110.3(B).

    It IS a REQUIREMENT, you apparently do not like it, nonetheless, though, *it is* a NEC code requirement - 310.15(B)(2)(a), (b), and (c).

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  18. #18
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    Default Re: Romex cable

    Interesting mess posted in the pics. I would not want to take any money inspecting that home. As said above... all the workmanship is far from A level including the I joists... location of water and romex and CAT and insulation and cut vapor barrier... Nothing in the pictures is done to high standards, nothing. Nothing is done to average standards... Will it all still work if left? Probably..

    I am learning quickly that maybe the inspection business is just not my cup of tea... I know I enjoy doing the work, being inspected and patted on the back for good work. We shall see.
    adkjac


  19. #19
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    Default Re: Romex cable

    Wow, your copy of the NEC must have more words than mine.

    310.15(B)(2)(a), (b), and (c) lots of words, but covers derating and says maintain spacing, but doesn't define what that spacing must be.

    110.3(B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

    Show me cable instructions or listing that defines what the minimum spacing must be. Show me panel instructions or listing that defines what the minimum spacing for cables or conduits entering the panel must be.

    Are you saying the conduits can't be offset to ever be closer than the knock-outs in a panel? I'd like to see that in writing from the manufacturer.

    It IS NOT a REQUIREMENT, you apparently do not like it, nonetheless, though, *it is not* specified in the NEC code requirement - 310.15(B)(2)(a), (b), and (c).


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    Quote Originally Posted by Tim Voss View Post
    Are you saying the conduits can't be offset to ever be closer than the knock-outs in a panel? I'd like to see that in writing from the manufacturer.
    From the 2008 NEC Handbook states: (which, I am sure, you will avow means nothing as to the intent of the code, even though it is produced for, by, and backed by, the NFPA - who just happen to also sponsor the production of, by and for, the NEC)

    - code-
    (b) More than One Conduit, Tube, or Raceway. Spacing between conduits, tubing, or raceways shall be maintained.

    - handbook commentary -
    Spacing is normally maintained between individual conduits in groups of conduit runs from junction box to junction box because of the need to separate the conduits where they enter the junction box, to allow room for locknuts and bushings. Field experience has indicated that this degree of spacing between runs had not caused any problems.

    Now, this is your assignment, call the NFPA and ask them if this means that they are using that spacing as the intended spacing referenced in the code in (b). If they tell you the same thing they told me years ago, the answer will be 'Yes, that has proven to have not caused any problems and thus is the spacing being referenced.', or similar wording to that affect. Meaning 'maintaining that spacing and it should be okie dokie, run the conduit runs together and you will need to start derating'.

    If, however, you are one of the ones who does not read 'supporting documentation' (i.e., the Handbook), then you will never understand it anyway.

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  21. #21
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    Default Re: Romex cable

    No need. I read the handbooks and the expert discussion. And while maintaining that spacing has "not caused any problems", maintaining a much closer spacing also has "not caused any problems". One of the reasons a minimum spacing is not "required" by the code. Only spacing.

    It would have been just as easy to say minimum spacing of 1/2" (or 1 inch or whatever), if that was the closest spacing found to not cause problems. But they didn't put that in the code, did they?


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    Quote Originally Posted by Tim Voss View Post
    And while maintaining that spacing has "not caused any problems", maintaining a much closer spacing also has "not caused any problems".
    That has not been tested, or proven, not even 'over time' as 'maintaining that spacing' has been tested (in the field) and proven (in the field).

    One of the reasons a minimum spacing is not "required" by the code.
    Minimum spacing is required, which is why it so states "maintain spacing". You put a conduit into a fitting into a knock-out or punched hole and install locknuts and bushing, then you "maintain that spacing" between it and the next closest conduit, even if placed as closely together so as to allow for the fitting, locknuts, etc. - that become the "minimum spacing" you are looking for, right there, and "that spacing" - that "minimum spacing" - is "to be maintained".

    Why not specify a given, specific spacing? The larger the conduit run, the larger the fitting, the larger the locknut, etc., the greater "the minimum spacing between them there will be". So, do you specify the wider spacing for smaller conduits? What a waste. Do you specify the smaller spacing for the larger conduits? Some idiot electrician would try to space them that closely, and the larger conduits will not fit that closely together.

    It would have been just as easy to say minimum spacing of 1/2" (or 1 inch or whatever), if that was the closest spacing found to not cause problems. But they didn't put that in the code, did they?
    See above explanation.

    Let's see, we take the largest conduit which will fit into a panel enclosure, say 2-1/2" (approximately 3" outside diameter), plus for the lock nut and grounding bushing - just in case it is needed (let's add 1/4" all the way around for that, or add 1/2" to the diameter, so now its outer diameter is 3-1/2"), you now add for some metal to remain around it and between the next hole, say 1/2" of metal, being as you've already added 1/4" all the way around for the lock nuts, etc., you only need to add another 1/4" all the way around, or another 1/2" to the diameter (which is now 4"). That allows 2-1/2" conduit to basically be installed so the lock nuts are touching, not a lot of "grounded metal" for them to ground to, and certainly not much metal left to try to hold those conduits in place.

    Be that as it may, we have now established that we need 4" diameter for each conduit. Period. (So you can have your easy way of looking at it.)

    Okay, that mean *ONE*, and ONLY *ONE*, conduit is allowed front to back (because the enclosure is not even 4" deep (yeah, that's a problem isn't it - so lets drop back to 2" conduit, that whacks off approximately 3/4" is diameter, yeah, that'll just about barely fit in the panel enclosure - so we've dropped back to 3-1/4" diameter for each conduit.

    Keeping it simple for you, mind you, don't want to complicate it.

    It would have been just as easy to say minimum spacing of 1/2" (or 1 inch or whatever), if that was the closest spacing found to not cause problems. But they didn't put that in the code, did they?
    Okay, in a 14" wide panel enclosure you are going to be able to install only 4 conduits across the top and 4 across the bottom, regardless if they are 1/2" conduits or not. To keep it simple, mind you. One size to fit all.

    Or, one could use their head and realize that various sizes of conduits would need to be spaced at various distances to allow each to be fully and properly installed, of course, though, that would take a whole new section to address all the potential size combinations which could be placed around each other.

    Yeah, that would really make it easy for you, wouldn't it?

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    Default Re: Romex cable

    So many problems would be eliminated if NM cable just wasn't used.

    Corey


  24. #24
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    Default Re: Romex cable

    I think you are grasping at straws there. Spacing could easily be defined as the space from the edge of one conduit to the next. Then it doesn't matter what size conduit you are using, just leave 1/4" gap from one to the next. But they didn't. Different panel manufacturers have different spacing of the knockouts in their panels.

    Show me in writing where it says the conduit spacing determined by the knockout locations in a panel must be maintained for those conduit runs.

    That is just silly.


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    Default Re: Romex cable

    Quote Originally Posted by Jerry Peck View Post
    As I said, the NEC DOES state what the minimum spacing is - in 110.3(B), which is specified by the manufacturers through the SPACING of their knock-outs for the NM cables.
    The manufacturer of a panel or other enclosure is not the manufacturer of the cable, so I would say that is a bit of a stretch, I don't disagree that bundling is bad, and some spacing is required, the spacing is the minimum amount they can have to be able to use a fitting adjacent to one another....

    If you really want to see a NM job see this link.
    ECN Electrical Forums: NM Run With An Iron.

    Last edited by Rollie Meyers; 08-23-2008 at 02:03 PM. Reason: Add link.

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    Default Re: Romex cable

    Quote Originally Posted by Rollie Meyers View Post
    The manufacturer of a panel or other enclosure is not the manufacturer of the cable, so I would say that is a bit of a stretch,

    Guess you missed that part in one of my posts above where I stated they (wire manufacturers) are some of the people I got my information from?

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    Default Re: Romex cable

    Quote Originally Posted by Jerry Peck View Post
    Guess you missed that part in one of my posts above where I stated they (wire manufacturers) are some of the people I got my information from?
    Verbal is not code, it's "gotta" be in writing..........


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    Quote Originally Posted by Rollie Meyers View Post
    Verbal is not code, it's "gotta" be in writing..........

    Rollie,

    It *IS* "in writing".

    What part of " *MAINTAIN* " do you and Tim not understand?

    You start of with a given spacing based on connector/fitting location relationship, then you " *MAINTAIN* " that spacing.

    I'm having a problem figuring out what part of "maintain" you and Tim *do not understand*.

    This is like trying to converse with a teenager who does not understand what "No." means nor do they understand that "No." is a complete sentence. Then, years later, "they understand".

    I sure hope we do not have to carry this on 'for years' until you and Tim "understand" what "maintain" means.

    Crimeny, how young are you and Tim?

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    Default Re: Romex cable

    Quote Originally Posted by Jerry Peck View Post
    Rollie,

    It *IS* "in writing".

    What part of " *MAINTAIN* " do you and Tim not understand?

    You start of with a given spacing based on connector/fitting location relationship, then you " *MAINTAIN* " that spacing.

    I'm having a problem figuring out what part of "maintain" you and Tim *do not understand*.

    This is like trying to converse with a teenager who does not understand what "No." means nor do they understand that "No." is a complete sentence. Then, years later, "they understand".

    I sure hope we do not have to carry this on 'for years' until you and Tim "understand" what "maintain" means.

    Crimeny, how young are you and Tim?
    Please state what you have in WRITING RE :requirements for spacing ,like specific manuf. instructions they have to be written as I said before.I am not from Missouri, but show me.


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    Default Re: Romex cable

    Quote Originally Posted by Rollie Meyers View Post
    Please state what you have in WRITING RE :requirements for spacing ,like specific manuf. instructions they have to be written as I said before.I am not from Missouri, but show me.
    Rollie,

    I *AM* trying to show you, but before I can show you ... YOU NEED TO OPEN YOUR EYES!

    From a previous post IN THIS THREAD:

    (Underlining, bold and red text are mine for highlighting purposes.)
    Quote Originally Posted by Jerry Peck View Post
    - 310.15 Ampacities for Conductors Rated 02000 Volts.
    - - (B) Tables. Ampacities for conductors rated 0 to 2000 volts shall be as specified in the Allowable Ampacity Table 310.16 through Table 310.19, and Ampacity Table 310.20 and Table 310.21 as modified by (B)(1) through (B)(6).
    - - - (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.
    Rollie,

    All you have to do it open your eyes and read then look at the original photo, which I've enlarged in case you have bad eyes.

    In the photo you will see NM cable clamps (which, by the way, should not have more than two NM cables in them, not the 5 or more as can be seen in the photo, and those two on the left have even more NM cables in the), you will notice that those two NM cable clamps have an initial distance separation between them.

    (Pause while Rollie looks and tries to wee what to heck I am talking about. Rollie, the two I marked with the red lines - those two. By the way, did you also notice the NM cable clamp to the left with the orange color NM cable in it, and the NM cable clamp to the right with the yellow NM cable in it?)

    Okay, you found those by now, I trust?

    First, though, let's pretend it was wired properly and that there are only two NM cables in each NM cable clamp, just trying to even up the playing field here.

    Okay, now, those two NM cable clamps which are marked with red lines ... do you see how far apart/close together those are?

    You have? Good.

    Now, let us go back and read the code, again, let's see, there it is: "multiconductor cables are installed without maintaining spacing" - see that? It is talking about the spacing between them, right there.

    Now that we have addressed the word "spacing" and identified it, let us go on to the other word of importance "maintaining" (see below).

    "multiconductor cables are installed without maintaining spacing" - and there that is too.

    BOTH are "in writing" and BOTH are "in writing in the NEC". How lucky could that be? One might even think it was INTENTIONAL!

    Okay, back to the photo ... Well, I will be danged! Look at that! "Spacing" was not "maintained"!

    Hmmmm, and what does the NEC state, "in writing", that you are supposed to do when that "spacing" is not "maintained"?

    Why, it says "the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a)."

    Holy molly! It was right there, and "in writing" too! Who woulda thunk that? Dang! Ya think it was INTENTIONAL?

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  31. #31
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    Default Re: Romex cable

    I agree with Rollie.

    The code says "maintain spacing". This does not mean you have to keep the spacing the same as where the cables exit the panel. That is ridiculous. According to your opinion, if I have one cable coming out of the left-most knockout and one coming out of the right-most knockout, those cables could never come closer than 14" from each other, or I wouldn't be maintaining the "spacing".


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    Default Re: Romex cable

    You keep evading answering the question about YOUR justification on what YOU say that the required spacing is the distance between KO's,and BTW, the picture is very good example of bundling ( We both agree that bundling is not kosher and my thought is, the whole mess in that pic
    should go to the scrapyard and start w/ a clean slate.) I am still waiting for a answer........


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    Default Re: Romex cable

    Quote Originally Posted by Tim Voss View Post
    I agree with Rollie.
    Yeah, I know that. Just trying to figure out why you can't read either.

    Quote Originally Posted by Rollie Meyers View Post
    You keep evading answering the question
    Rollie (and Tim),

    (sigh)

    Let me start another way and see if that light bulb in your head lights.

    You see a sign which states "Road Slippery When Wet" and "Maintain Safe Speed" ... how fast (or slow) do you drive?






    Why that fast (or slow)?

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    Default Re: Romex cable

    You still have not answered my question.(Yes,spacing the cables is required. ) All I ask is documentation on your statement the required spacing is the KO spacing on the enclosure is the spacing that is required to be maintained,all I have read is snide remarks, but no proof which leads me to the conclusion that you have none.


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    Default Re: Romex cable

    Quote Originally Posted by Rollie Meyers View Post
    You still have not answered my question
    I have answered it in about as many ways as I can think of trying to explain it.

    Do you know what "maintain" means?

    Please tell my what "maintain" means to you ... in your own words.

    Jerry Peck, Construction / Litigation Consultant
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  36. #36
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    Default Re: Romex cable

    There are plenty of different ways to look at that installation; what's difficult is to set aside and notion that "butt ugly" is a code violation. (Sure, the NEC does mention 'neat and workmanlike;' but the NFPA long ago conceded that such a provision was unenforceable).

    Whether the wall will be closed in is a major factor to consider. So is the distance involved.

    Packed with insulation, and closed in, under the 2008 code derating would need to be considered. Prior to the 2008 code, you needed to have at least two feet of "bundled" cable for derating to be required. How many cables pass through one hole has no bearing on the decision to derate.

    Let's not turn "maintaining spacing" into the modern equivalent of debating how many angels can dance on the head of a pin. There certainly was no attempt in this install to either space, or to make a nice bundle.

    Looking at that feeder, I doubt that they plan to close in this area. With the entire front exposed, I'd say there's ample opportunity for heat to dissipate. Close it in, and you better be planning to do so with steel plate; I can't see any way to maintain the 1-1/2" distance from the face. A screw into that feeder would be real hard on the tool warranty

    The one thing that can't be denied is the improper use of clamps at the panel. Simply put, I'm not aware of any clamps that are approved for use with more than two cables. This guy, it seems, didn't want to use a bunch of little clamps. (In similar panels, I've often had to use EVERY available KO).

    Another item worth mentioning is the manner of the wires passing through the I-joists. Contrary to common belief, there is no requirement to use the 'factory' KO's. There is absolutely nothing wrong with small holes anywhere in the web.


  37. #37
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    Default Re: Romex cable

    Quote Originally Posted by Jerry Peck View Post
    As best I can see in the photo, the left 'bunch' at the panel starts out as one 'bunch' of 11-12 cables, albeit for less than 24", probably about 12"+/-. Thus, we only need to go up another 12", and in this case there are 2 'bunches' of cables, the left having 4 2-conductor cables for 8 conductors and the right having 7-8 2-conductor cables for 14-16 conductors ... for well over 24".

    Now let's address "derating", what it is based on, and how it is supposed to be done.

    Let us presume 90 degree C rated insulation, which means that #12 NM-B has a theoretical ampacity of 30 amps before applying any derating. Remember, though, it must still be protected at 20 amps or less.

    30 amp rating before derating for ambient temperature (which is always the first derating applied).

    Let's presume that one or more of those goes up into the attic, which we will presume gets to 135 degrees F during the peak heat of the summer. Oh? You say it does not get that hot, it only gets to 125 degrees F? Okay, let us start there, 135 degrees just gets worse, so we will go with 'best case'.

    The 30 amp rating is derated to o.76 of the previous rating value, so 30 x 0.76 = 22.8 amps. Okie dokie, that still meets the rating for a 20 amp breaker.

    Now, though, the derated rated for ambient is 22.8 amps (and that is with an attic of only 125 degrees F).

    Now we apply the "lack of maintaining spacing" derating.

    The 'bunch' with 8 conductors gets derated as follows: 22.8 amp rating gets derated to 70% when there are 7-9 conductors together, or, 22.8 x 70% = 15.96 amps derated rating.

    The 'bunch' with 11-12 conductors gets derated as follows: 22.8 amp rating gets derated to 50% when there are 10-20 conductors together, or, 22.8 x 50% = 11.4 amps derated rating.

    And you want to put those on a 20 amp breaker?


    Correct me if I am wrong....

    But unless all those conditions happen in the same space, I am not sure you can add the deratings and get one LARGE derating. The bunch of 11-12 conductors, with a derating of 50% of 30A would give you 15A, OK still too little for a 20A Breaker.

    BUT

    The section of 7-9 conductors, unless it is also in the attic at the same tiime it is bundled up, would be 21A (30 X .7 = 21) If the 7-9 conductors fan out once they reach the attic space, the 'bundling' derating should no longer apply, and only the ambient temp derating of 76% which would give you 22.8A. if they didn't fan out, and we apply both factors 70%, and the 76% we end up with 15.96A

    But it still looks like a mess.....

    John


  38. #38
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    Default Re: Romex cable

    Jerry Peck asked:
    You see a sign which states "Road Slippery When Wet" and "Maintain Safe Speed" ... how fast (or slow) do you drive?
    Why that fast (or slow)?
    I would drive as fast as I could, while still being safe. This would mean constantly adjusting my speed to account for the road conditions, which can change as I encounter rough, wet or slippery patches. Why? Fast, because I want to get where I'm going in a reasonable amount of time. Not as fast as I want, because I want to be safe.

    So, Maintain Safe Speed means to adjust your speed as necessary.

    Thank you Jerry, you helped me realize a way to explain my position.

    The code does not say "Maintain Uniform Spacing", which is what you are saying. Maintain spacing means to keep the wires separated with "air" space that can vary as necessary, as long as the cables don't come in contact.


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    Default Re: Romex cable

    Quote Originally Posted by Tim Voss View Post
    I would drive as fast as I could, while still being safe. This would mean constantly adjusting my speed to account for the road conditions, which can change as I encounter rough, wet or slippery patches. Why? Fast, because I want to get where I'm going in a reasonable amount of time. Not as fast as I want, because I want to be safe.

    So, Maintain Safe Speed means to adjust your speed as necessary.

    Thank you Jerry, you helped me realize a way to explain my position.
    First, Tim, you are not "maintaining" a safe speed, you are "varying" your speed. "Varying" and "maintaining" do not have the same meaning - look them up.

    Okay, now you are in the spot you were trying to put me in ...

    Precisely ... HOW FAST/SLOW would you drive. You have to give a number, a hard and fast number. That's what you wanted from the code, now it is your turn to state it.

    Previously you stated: "It would have been just as easy to say minimum spacing of 1/2" (or 1 inch or whatever), if that was the closest spacing found to not cause problems. But they didn't put that in the code, did they?"

    Now you see why the NEC could not state a specific number, don't you?

    The code does not say "Maintain Uniform Spacing", which is what you are saying. Maintain spacing means to keep the wires separated with "air" space that can vary as necessary, as long as the cables don't come in contact.
    No, that is not "maintaining spacing", that is "varying spacing", by your own description.

    To "maintain" something, you have to start out at a given level, in this case, a given distance, and that given distance is the distance separation between the NM cable clamps ... and the NEC *REQUIRES* you to "maintain" that spacing, whatever that spacing happens to be - which (as in your driving example) will vary depending on conditions, and the "conditions" upon which this varies is "the original spacing where the NM cable clamps are located.

    Any *other* spacing and you are not "maintaining" anything, you are "varying it" - which is far from "maintaining" it.

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  40. #40
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    Default Re: Romex cable

    Jerry,

    Since you didn't answer my question, I will ask again:

    I have a cable coming out of the left KO and another cable coming out of the right KO and they are 14" apart. So are you saying that if I bring these cables closer than 14" together, then I have violated the "maintain spacing"?


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    Default Re: Romex cable

    If you were to have 2 cables installed in the same connector, as many are listed, what spacing would you be required to maintain?

    What about when those 2 wires are under the same staple?

    What cable spacing would be required to be kept in a rigid nipple into the top of a surface mounted enclosure? How would you maintain cable spacing in a nipple between 18" and 10' long?

    Why are you allowed closer spacing using larger cables when using concentric knockouts?

    To say that the minimum cable spacing required to be maintained is determined by the space required to allow a locknut to properly spin is a stretch. A parking lot space is designed for a typical vehicle. Can you park 2 motorcycles in one space? You are not maintaining the designed spacing.

    Last edited by Jim Port; 08-27-2008 at 08:30 AM. Reason: added concentric question

  42. #42
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    Default Re: Romex cable

    Quote Originally Posted by Tim Voss View Post
    Jerry,

    Since you didn't answer my question, I will ask again:

    I have a cable coming out of the left KO and another cable coming out of the right KO and they are 14" apart. So are you saying that if I bring these cables closer than 14" together, then I have violated the "maintain spacing"?

    Tim,

    You've never asked that question before, or, if you did, I missed it. If you did, would you kindly point me to which post it was in, thanks.

    To answer your question, though, no, not as you stated in your question, you would go back to what I've stated in my posts before.

    First, let's apply your question to what I've stated before, which, it seems, you have missed.

    Let's move the two NM cables together into two adjacent knock-outs ... yes, you maintain that spacing.

    You start off with a given spacing, two NM cables in adjacent knock-outs, and you *MAINTAIN* "that spacing".

    Second, let's go back to your question of two NM cables being installed in knock-outs at opposite sides of the enclosure, knock-outs which are 14" apart.

    You look at those two NM cables, then look at the knock-outs adjacent to each, and you would "maintain" that intended spacing between adjacent knock-outs - not between two distant NM cables.

    Someone said you can punch as many holes in the top/side/bottom as you want, just leaving small webs between the NM cable clamps - first, that would destroy the integrity of the enclosure, so, no, you cannot just willy-nilly take a punch and 'shotgun' the enclosure full of holes.

    Besides, you would need to space the NM cable clamps *at least far enough from each other to allow for lock nuts, bushings, etc.* ... but I have said that before too.

    There is no "magical number" to use to "maintain spacing" ... I've said that before too ... but you have to base it on what was intended ... and I've said that before too ... and what you can do (such as the punching holes with sufficient spacing to allow for all the goodies ... and, yes, I've said that before too.

    Can you put 2 NM cables together? Sure.

    Can you put 2 NM cables together and not have them touch? Sure.

    Can you put 4 NM cables under one staple? Sure.

    Notice, though, that I said "can you", not "may you". You "can do" many things you are "not allowed" to do, some of which you are simply "not allowed" to do, others of which you "can do, and are allowed to do" as long as you do "something else too" - in this case that "something else too" is derate the ampacity.

    Heck, the code allows for 100 NM cables bundled together, wrapped in a tight bundle with tape around them.

    Absolutely does allow for that.

    Of course, though, it also "requires" you to derate their ampacity ratings to 35% of the listed ampacity ratings (after ambient derating) if you chose to do that.

    Can you do that? Sure.

    Are you allowed to do that? Sure.

    You mean I can bundle every single one of the conductor runs in my house together and make it look nice and neat, running them all in the same location?

    You betcha - no problemo.

    Just make sure you follow through and do what is required if you chose to do that, that's all.

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    Default Re: Romex cable

    Hi guys, question, the clamps that secure the cables to the panel, where they enter the panel, are all rated for only a certain number of wires each, are they not? There's an awful lot of wire going through a couple of those clamps.


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    Default Re: Romex cable

    Jerry I have a question for you cause I can't find the answer here. I recently was reading posts about the plumbing and wiring of an garberator that had a dishwasher running into it. The fella was concerned about the plumbing. Each sink had its own trap and run to the drain which you guys enjoyed seeing. My question is this, there was some romex running to the garberator I believe and you stated it needed to be FMC. Would this not be considered a wet zone? Being under the sink and all? Thanks


  45. #45
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    Default Re: Romex cable

    Just thought I could add my experience to being inspected over the years. In my area electric inspections are paid for by the builder/electrician and are done through private inspection agencies. And in my county some towns have building inspectors for all the rest of the code and some towns let the county inspect.

    All that said... here is my 25 years of inspection history... I have had one electric box opened in all that time. The last home I just finished was a talking walk around counting number of installed devices to put on the inspection report which ended at an open main panel that the inspection approved sticker was put on. Now if you know the code, the open main was not allowed even and didn't even stop the chit chat for a second.

    Another side note... second home ever built by myself... called for final CO... inspector says hi hi hi... oh great... you're done... I will send out the CO and you should have it tomorrow! I asked if he was coming up as I wanted to be inspected and he said... I do nice work and he will see me on the next job kinda thing....

    Now... it may not go that nicely for hacks that get inspected... I just don't know.... One thing I do know is that any time I visit construction sites for fun and curiosity... or maybe to learn what others do to help me... I often find plumbing run flat or over pitched... electric is always stapled with multiple romex under staples, more than three conductors run in large joist holes... and joists drilled where not allowed.

    Thankfully the code most of the time is overkill. We did just have a new home burn to the ground because a piece of romex was squeezed over a cellar beam from shrinkage of the framing settling and pinching.

    adkjac

    As to you two going on for days over the spacing... interesting but getting a bit old don't yaa both think? Space wires is the way to go... and as to the job in the photo.. get the owner to improve all a tiny bit if he desires or walk away seems like what I might do not knowing all the facts.... seems like there may be many other ways to handle this too since I am not an inspector yet.


  46. #46
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    Default Re: Romex cable

    Quote Originally Posted by Jim Port View Post
    If you were to have 2 cables installed in the same connector, as many are listed, what spacing would you be required to maintain?

    What about when those 2 wires are under the same staple?
    Jim,

    If you do the derating on on those 2 NM cables, 2 conductors each, 4 conductors total, under derating in all but the very hottest of attics, the derated rating will still allow for the same size overcurrent protection to be used. Thus, with 2 12-2 w/g NM cables in one cable clamp, under one staple, the derating would make it acceptable for use on a 20 amp breaker.

    No harm, no foul.

    What cable spacing would be required to be kept in a rigid nipple into the top of a surface mounted enclosure? How would you maintain cable spacing in a nipple between 18" and 10' long?
    The correct answer to that is to answer what was *not* asked: How would you meet the requirement for securing the NM cables to the enclosure?

    However, to answer your question, why would you maintain spacing in a nipple less than 24" long? Derating does not kick in until the nipple is greater than 24" long.

    To say that the minimum cable spacing required to be maintained is determined by the space required to allow a locknut to properly spin is a stretch. A parking lot space is designed for a typical vehicle. Can you park 2 motorcycles in one space? You are not maintaining the designed spacing.
    How many vehicles are *legally* allowed in one parking space? One.

    Is a "motorcycle" a "vehicle"? Yes.

    Have you not seen "motorcycle sized" parking spaces marked "motorcycle parking only"? Wait, maybe not, but I live in Ormond Beach, which is right next to Daytona Beach, which has Bike Week and Biketoberfest, and which has motorcycle parking areas - so maybe this area is unique in having those motorcycle parking spaces? I seem to remember having seen them in South Florida also?

    How many angels can you fit on the head of a pin? Depends.

    How big is the head of the pin?

    How small are angels?

    How bossy are angles? Do they mind being crammed together? What if their motorcycles touch each other? Do they get ticked off?

    Does the question include cramming their wings together? Do angels mind that?

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Romex cable

    Quote Originally Posted by Brian Robertson View Post
    Hi guys, question, the clamps that secure the cables to the panel, where they enter the panel, are all rated for only a certain number of wires each, are they not? There's an awful lot of wire going through a couple of those clamps.
    Typically those NM cable clamps are rated for two flat-type (2 conductor plus ground) NM cables, or, 1 round (3 conductor plus ground) NM cable.

    Same applies to staples.

    Quote Originally Posted by Brian Robertson View Post
    Jerry I have a question for you cause I can't find the answer here. I recently was reading posts about the plumbing and wiring of an garberator that had a dishwasher running into it. The fella was concerned about the plumbing. Each sink had its own trap and run to the drain which you guys enjoyed seeing. My question is this, there was some romex running to the garberator I believe and you stated it needed to be FMC. Would this not be considered a wet zone? Being under the sink and all? Thanks
    "garberator"? New term for me.

    You mean (technically) "food waster grinder", commonly known as garbage disposer, etc.

    No, the under-sink area is not considered a wet location as no water should be getting into that area. If you have water getting into that area, you have a leak, and that leak needs to be repaired. That would be considered "normally dry" as that is the intent ... keeping that area "dry".

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    Default Re: Romex cable

    Quote Originally Posted by adkjac View Post
    Thankfully the code most of the time is overkill.

    You really have me confused with that comment.

    "code" is "minimum"

    There is no "overkill" to "code", it is the absolute minimum you are legally allowed to build to.

    I've said this before, but ... "code" is not something you get up in the morning and say "I think I will try to build to code today", no, "code" is not something your "strive for", "code" is the lowest level "you are legally allowed to start at" - you can do as much better as you want to. That is where "value" comes in ... by "doing more/better than is required".

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  49. #49
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    Default Re: Romex cable

    Quote Originally Posted by Jerry Peck View Post
    You really have me confused with that comment.

    "code" is "minimum"

    There is no "overkill" to "code", it is the absolute minimum you are legally allowed to build to.

    I've said this before, but ... "code" is not something you get up in the morning and say "I think I will try to build to code today", no, "code" is not something your "strive for", "code" is the lowest level "you are legally allowed to start at" - you can do as much better as you want to. That is where "value" comes in ... by "doing more/better than is required".
    Until they think they are doing better than code and really mess things up and unsafe. I have seen that plenty of times. You always get "but we did it better than code"


  50. #50
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    Default Re: Romex cable

    Jerry,

    I had posed that question in #31.

    Here is the major dissagreement:

    ...and you would "maintain" that intended spacing between adjacent knock-outs - not between two distant NM cables.
    The code does NOT say that the distance between adjacent knock-outs is the intended spacing that is to be maintained. The panel manufacturers do not say that in their instructions. You believe that the handbook says this, and I agree that the practice is recommended, but it is NOT CODE.

    There are numerous discussions about this code issue in electrical forums and the one thing that experts are in agreement about is that the code does not specify what it is. It is up to the AHJ to determine how much space is necessary.


  51. #51
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    Default Re: Romex cable

    Jerry... I am not here to argue. Codes rely on engineering and engineering certainly if you went to college for it involves designing in safety factors that equate to a percentage above minimum. I build aircraft and homes... have built 11 planes and many homes. I have worked on 100 year old camps with perfect roofs in snow country that have 2x4 rafters.

    So.. I will agree to disagree about codes being overkill most of the time.

    I agree that codes are legally the minimum.

    I also know that many of us in the trades proudly build to better than the codes.

    I also know that as to saving energy, the codes do not aid inspectors in understanding at all how to build stick frames with less wood in headers and jack stud areas. I use way less wood in my frames to create homes that are more energy efficient. For example we use 2nd floor rim joists to support loads of first floor windows so a non structural header can be insulated to higher R.

    Green building and the ramp up to net zero energy use homes is here and is very much where I am now headed. Good luck to all of the inspectors here.... Green Building should generate lots more work for all as it is all about documentation and inspecting. LEED AP's who isn't one these days?

    adkjac

    Jerry... we need to share a cocktail... and get back on the volleyball court or back to work. Peace.


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    Default Re: Romex cable

    You have taken the question of maintaining required spacing into a debate on derating. The issue is not about what derating factor to use or if it even applies.

    The question was how is the required spacing maintained in various situations including sleeves between 18" and 10'.

    You turned this into how is the cable secured to the enclosure. Again, not the question asked. Here is a similar application that shows how this is accomplished.


    I guess a lot of people are also confused by terminology like air bags and jet skis. More precisely called supplemental restraint devices or personal watercraft. But somehow we manage.


  53. #53
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    James Duffin Guest

    Default Re: Romex cable

    The houses I inspect are built in the real world. I use my judgment to determine if something is unsafe. To nit-pick a job to death because you can is silly. I'm sure nobody will agree but that really does not matter does it!?


  54. #54
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    Default Re: Romex cable

    Quote Originally Posted by Jim Port View Post
    What cable spacing would be required to be kept in a rigid nipple into the top of a surface mounted enclosure? How would you maintain cable spacing in a nipple between 18" and 10' long?
    Quote Originally Posted by Jerry Peck View Post
    If you do the derating on on those 2 NM cables, 2 conductors each, 4 conductors total, under derating in all but the very hottest of attics, the derated rating will still allow for the same size overcurrent protection to be used. Thus, with 2 12-2 w/g NM cables in one cable clamp, under one staple, the derating would make it acceptable for use on a 20 amp breaker.

    No harm, no foul.

    The correct answer to that is to answer what was *not* asked: How would you meet the requirement for securing the NM cables to the enclosure?

    However, to answer your question, why would you maintain spacing in a nipple less than 24" long? Derating does not kick in until the nipple is greater than 24" long.
    Jim,

    I made *AN ASSUMPTION* that you were referring to more than two NM cables. If you were (my assumption) then derating would be required because you could not maintain spacing.

    Being as you *could not* maintain spacing, I set aside thinking you were referring to *just two* NM cables for the reasons I mentioned above in my post - derate 2 2-conductor NM cables (4 conductors total) and you still fall within using the same breaker size.

    Thus, I *ASSUMED* you meant *more than two* 2-conductor NM cables.

    *MY ERROR*

    *IF*, and only if, you use 2 2-conductor NM cables in that conduit, your question is moot - there is no way to "maintain spacing" and, as such, you would derate and, as I stated above, no harm, no foul.

    Now, regarding your answer to my other statement:

    Quote Originally Posted by Jim Port View Post
    You turned this into how is the cable secured to the enclosure. Again, not the question asked. Here is a similar application that shows how this is accomplished.
    This code is also applicable to that question/statement:

    From the 2008 NEC. (underlining is mine)
    - 312.5 Cabinets, Cutout Boxes, and Meter Socket Enclosures.
    - - (C) Cables. Where cable is used, each cable shall be secured to the cabinet, cutout box, or meter socket enclosure.
    - - - Exception: Cables with entirely nonmetallic sheaths shall be permitted to enter the top of a surface-mounted enclosure through one or more nonflexible raceways not less than 450 mm (18 in.) and not more than 3.0 m (10 ft) in length, provided all of the following conditions are met:
    - - - - (a) Each cable is fastened within 300 mm (12 in.), measured along the sheath, of the outer end of the raceway.
    - - - - (b) The raceway extends directly above the enclosure and does not penetrate a structural ceiling.
    - - - - (c) A fitting is provided on each end of the raceway to protect the cable(s) from abrasion and the fittings remain accessible after installation.
    - - - - (d) The raceway is sealed or plugged at the outer end using approved means so as to prevent access to the enclosure through the raceway.
    - - - - (e) The cable sheath is continuous through the raceway and extends into the enclosure beyond the fitting not less than 6 mm ( in.).
    - - - - (f) The raceway is fastened at its outer end and at other points in accordance with the applicable article.
    - - - - (g) Where installed as conduit or tubing, the allowable cable fill does not exceed that permitted for complete conduit or tubing systems by Table 1 of Chapter 9 of this Code and all applicable notes thereto.
    - - - - - FPN: See Table 1 in Chapter 9, including Note 9, for allowable cable fill in circular raceways. See 310.15(B)(2)(a) for required ampacity reductions for multiple cables installed in a common raceway.

    *IF* all the above exception requirements are met, then no NM cable clamp is required at the enclosure.

    *HOWEVER*, if more than one NM cable in installed in that conduit or raceway, then spacing CANNOT be maintained, and derating IS REQUIRED. One (the exception allowing the NM cables to be in the conduit) *does not* negate the other (the derating requirement).

    Put *more than two* 2-conductor NM cables in that conduit and the derating will cause a reduction in their allowable overcurrent protection.

    Hopefully I have covered all of which you have asked, and even more.

    I know I answered these:

    Q1) How can you maintain spacing in that conduit?

    A1) You can't, and derating applies.

    Q2) (this was more of a statement) You do not need to secure the NM cables *WITHIN* the conduit.

    A2) Agreed, there is *NO WAY* to secure the NM cable "WITHIN" the conduit. Just like there is *NO WAY* to maintain spacing within the conduit. That does not negate the requirement for derating, though. Plus, all those conditions for that exception must be met - *all of them*.

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

  55. #55
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    Default Re: Romex cable

    The minimum spacing distance is an issure that needs to be addressed by the NFPA. This is a question that is not addressed properly at any level; not in engineering schools or the National Electric Code. In my opinion the amount of spacing given by knockouts in a standard junction box should be the minimum distance allowed for a conductor not to be considered bundled.


  56. #56
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    Default Re: Romex cable

    Unreal I got an e-mail today about this post so whatever here goes, Jerry, the reason we need GFCI's within 6 feet of sinks etc. and I'm sure you have a different name for sink, or maybe I should call it "water receptacle capable of washing dishes etc." ? No, there's no way that would work, perhaps .... irregardless; if you explained it in the 7,000 word explanation you gave or not, who cares, is the reason certain areas are required to have GFCI"s because they are considered "wet" area"s or not? And I'm sure you will do your best to make me look foolish on this account so I will not be checking in here again, so save your comments for someone who cares cause I won't see them. Thanks


  57. #57
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    Default Re: Romex cable

    Quote Originally Posted by Jeremy Crowell View Post
    The minimum spacing distance is an issure that needs to be addressed by the NFPA. This is a question that is not addressed properly at any level; not in engineering schools or the National Electric Code. In my opinion the amount of spacing given by knockouts in a standard junction box should be the minimum distance allowed for a conductor not to be considered bundled.
    Any reason other than a personal opinion you have for this arbitrary spacing - like proof of conductor damage or framing material damage from heat buildup?

    Most NM box connectors allow two cables per opening. We gonna change this now?

    How many holes per side of what size box are we talking?

    Frankly, I don't see that most cables that aren't in intimate contact for extended distances have a problem and that the "not maintaining spacing" blurb seems to work just fine.

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

  58. #58
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    Default Re: Romex cable

    Quote Originally Posted by Bill Kriegh View Post
    Any reason other than a personal opinion you have for this arbitrary spacing - like proof of conductor damage or framing material damage from heat buildup?
    I agree with this questioning of your position.

    Most NM box connectors allow two cables per opening. We gonna change this now?

    How many holes per side of what size box are we talking?
    I also agree that this creates a wrinkle on just what is "maintaining spacing".

    Frankly, I don't see that most cables that aren't in intimate contact for extended distances have a problem and that the "not maintaining spacing" blurb seems to work just fine.
    I disagree with the presumption above that the code is addressing "intimate contact" as the code does not address that at all, the code is addressing "spacing" and "maintaining" that spacing.

    I think the code is at a good start where the NEC now limits the numbers of NM cables through holes in framing which are to be insulated - previously the code had no limitation on this used-all-the-time-practice of stuffing as many cables through one hole as one could fit through the hole.

    That is no longer allowed - the limitation is two cables through that one hole ... THAT is a HUGE reduction over what electricians considered acceptable practice.

    Now all we need to do is to show those same electricians that "maintaining spacing" means ... well, that it actually mean "maintaining spacing", not that you are allowed "intimate contact" all over the place ... what those electricians thinking - that the NM cables will reproduce and thus provide more conductors, therefore the more "intimate contact" the better?

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

  59. #59
    Robert Meier's Avatar
    Robert Meier Guest

    Default Re: Romex cable

    Quote Originally Posted by Jerry Peck View Post
    I think the code is at a good start where the NEC now limits the numbers of NM cables through holes in framing which are to be insulated - previously the code had no limitation on this used-all-the-time-practice of stuffing as many cables through one hole as one could fit through the hole.

    That is no longer allowed - the limitation is two cables through that one hole ... THAT is a HUGE reduction over what electricians considered acceptable practice.
    Actually you can use more than two cables but you just need to apply derating factors. You can still stuff 10 cables in a sealed hole if they're all properly derated.


  60. #60
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    Default Re: Romex cable

    Quote Originally Posted by Robert Meier View Post
    Actually you can use more than two cables but you just need to apply derating factors. You can still stuff 10 cables in a sealed hole if they're all properly derated.
    Opps ... DANG! ... I forgot to add that into my post.

    I meant to say "blah, blah, blah ... unless derating is applied" ... my bad!

    The electrician I was responding to and I have been debating the finer issues of derating and when to apply them (Me: frequently; Him: seldom to never ), I was kind of razzing him about having to derate for those conductors and totally forgot to include the main part - that they need to be derated if more than two are in those holes. Me bad.

    Thank you for pointing that out!

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

  61. #61
    Darrel Hood's Avatar
    Darrel Hood Guest

    Default Re: Romex cable

    Everybody in this debate is right. In every design dimension or mandated clearance, there must be an allowance for imperfection. The allowance is sometimes called a tolerance. Since there is no stated tolerance for JP's "maintain spacing", the tolerance is in the eyes of the beholder. Consequently if we apply a tolerance of a coupla inches, we can bundle up and stay warm.


  62. #62
    Garry Blankenship's Avatar
    Garry Blankenship Guest

    Default Re: Romex cable

    There are two main reasons for not bundling / grouping too many cables together. The most important being heat and the aggregate heat build up potential of many cables bundled together. The second reason is EMFs or transients being induced from conductor to conductor which can not only aggrevate heat build up but negatively effects how lots of electrically powered devices operate - - - especially computers. The bulk of this concern is with cables tightly bundled inside conduits. Those problems rarely manifest in NM installations and bundling violations tend to be ignored in NM installations. The blue cables, ( voice/data / low voltage ), do not have the horsepower to create those problems like line voltage cable; plus they are often shielded which diminishes the transients problem. So bundling low voltage cables basically is not a concern. Bundling them with line voltage cables is.


  63. #63
    Robert Rolleston's Avatar
    Robert Rolleston Guest

    Default Re: Romex cable

    Is this no experience homeowner built? Or hangover/drunk electrician day?


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