Thread: Romex is attic

The romex cable was laying on the attic walkway which had been installed to gain access to the funace. Is this allowable.

Mat

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IRC says something on these lines.
APPLIANCES IN ATTIC:
: Attics containing appliances requiring access shall be provided with an opening and a clear and unobstructed passageway large enough to allow removal of the largest appliance, but not less than 30 inches high and 22 inches wide and not more than 20 feet in length. The passage way shall have continues solid flooring not less than 24 inches wide. A level service space at least 30 inches deep and 30 inches wide shall be present along all sides of the appliance where access is required. The clear access opening dimensions shall be minimum of 20 inches x 30 inches.

Says clear and unobstructed. Service people could trip over the wires.

Also, NM needs protection close to the access hole and walkways.

Originally Posted by mathew stouffer

Is this allowable.

No.

The NM cable needs to be protected in some manner, such as installing 1x or 2x (depends on how high the NM cables are stacked) runners on each side and covering the NM cable with plywood (making the floor platform go up and over the NM cable).

Also, looks to me like they have a bundling/lack of maintaining spacing problem with the NM cables too (and definitely will if the above it done), making those circuits needing derating. With as many NM cables as I see - looks like at least 8-10 12-2 NM cables in the far group, making 16-20 conductors in that group - the derating factor would be 50% ... making those 20 amp circuits more like 10 amp rated (derated) circuits.

Your pictures indicate the original electrician ran his branch circuit wiring correctly on "running boards across the attic joists. See NEC/2005 section 334.23. This is acceptable and the spacing is also acceptable because the runs are side by side, spaced about one cable width and appear to be secured with staples. The plywood in the photos is NOT a walkway in this case. The new run of romex needs to be secured on the running board same as the ones in the photo. If the plywood is used as access, then 2x3s on edge and another stip of plywood over the 2x3s makes the arrangement safe from mechanical damage during attic access. The open air space left afterwards is adequate and will not need derating. The derating is only applicable for bundled cables or cables in conduits over 24 inches long.

Nathaniel,

First, welcome to THE inspectors forum.

Originally Posted by Nathaniel Johnson

Your pictures indicate the original electrician ran his branch circuit wiring correctly on "running boards across the attic joists. See NEC/2005 section 334.23. This is acceptable

This is acceptable only if: 1) not within 6 feet of the attic access opening, and, 2) not if the plywood is a walkway. As the original poster stated it was a walkway, then it is not acceptable, *even if* within 6 feet of the attic access.

and the spacing is also acceptable because the runs are side by side, spaced about one cable width and appear to be secured with staples.

If only that had been done. Are you looking at the closer bundle/lack of maintaining spacing or the further one? The closer one is closer to what needs to be done, however, if you look closely, you will see that there is an NM cable laying on top of another NM cable, and that *is not* acceptable. Look at the second photo and you will see the first yellow (12-2) NM cable is spaced from the second yellow NM cable - and there is another NM cable below the second one.

The further back you go in the bundle/lack of maintaining spacing, the worse it gets.

Hopefully you are not an electrician and would not do that type of work, and, even more hopefully you ware not an electrical code inspector and would not accept that kind of work.

The plywood in the photos is NOT a walkway in this case.

How can you, who was not present, state that the plywood was NOT a walkway, when the original poster, who was there, specifically stated it was a walkway?

If the plywood is used as access, then 2x3s on edge and another stip of plywood over the 2x3s makes the arrangement safe from mechanical damage during attic access. The open air space left afterwards is adequate and will not need derating.

Incorrect. They require derating as installed now, placing another piece of plywood over the NM cables without spacing them apart does nothing but make matters worse.

The derating is only applicable for bundled cables or cables in conduits over 24 inches long.

You need to go back and re-read that section.

From the 2008 NEC (unchanged for years). (bold and underlining are mine)
- 310.15 Ampacities for Conductors Rated 0–2000 Volts.
- - (B) Tables.
- - - (2) Adjustment Factors.
- - - - (a) More Than Three Current-Carrying Conductors in a Raceway or Cable. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are installed without maintaining spacing for a continuous length longer than 600 mm (24 in.) and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a). Each current-carrying conductor of a paralleled set of conductors shall be counted as a current-carrying conductor.
- - - - - FPN No. 1: See Annex B, Table B.310.11, for adjustment factors for more than three current-carrying conductors in a raceway or cable with load diversity.
- - - - - FPN No. 2: See 366.23(A) for adjustment factors for conductors in sheet metal auxiliary gutters and 376.22(B) for adjustment factors for conductors in metal wireways.
- - - - - Exception No. 1: Where conductors of different systems, as provided in 300.3, are installed in a common raceway or cable, the derating factors shown in Table 310.15(B)(2)(a) shall apply only to the number of power and lighting conductors (Articles 210, 215, 220, and 230).
- - - - - Exception No. 2: For conductors installed in cable trays, the provisions of 392.11 shall apply.
- - - - - Exception No. 3: Derating factors shall not apply to conductors in nipples having a length not exceeding 600 mm (24 in.).
- - - - - Exception No. 4: Derating factors shall not apply to underground conductors entering or leaving an outdoor trench if those conductors have physical protection in the form of rigid metal conduit, intermediate metal conduit, or rigid nonmetallic conduit having a length not exceeding 3.05 m (10 ft) and if the number of conductors does not exceed four.
- - - - - Exception No. 5: Adjustment factors shall not apply to Type AC cable or to Type MC cable without an overall outer jacket under the following conditions:
- - - - - - (1) Each cable has not more than three current-carrying conductors.
- - - - - - (2) The conductors are 12 AWG copper.
- - - - - - (3) Not more than 20 current-carrying conductors are bundled, stacked, or supported on “bridle rings.”
- - - - - - - A 60 percent adjustment factor shall be applied where the current-carrying conductors in these cables that are stacked or bundled longer than 600 mm (24 in.) without maintaining spacing exceeds 20.
- - - - (b) More Than One Conduit, Tube, or Raceway. Spacing between conduits, tubing, or raceways shall be maintained.
- - - - (c) Conduits Exposed to Sunlight on Rooftops. Where conductors or cables are installed in conduits exposed to direct sunlight on or above rooftops, the adjustments shown in Table 310.15(B)(2)(c) shall be added to the outdoor temperature to determine the applicable ambient temperature for application of the correction factors in Table 310.16 and Table 310.18.
- - - - - FPN: One source for the average ambient temperatures in various locations is the ASHRAE Handbook — Fundamentals.

Not "may be reduced" ... "shall be reduced".

Many people, and you, read the bundling part and skip over the lack of maintaining spacing part. The lack of maintaining spacing part is just as critical as the bundling part.

Jerry


If this were your inspection or if your were consulted to as what would make this situation right, what would you advise. Obviously it would not be just removing the plywood so it could not be called a walkway. Short of a complete rewire as in the spacing/bundling the code suggests. I doubt if wire lengths would permit all that. Sounds like things could get pretty expensive.

Thanks
Ted

Jerry, thanks for you response. I respect your position. If this is new construction, then the contractor has a problem in that the electrician installed his wiring on the walkway. If the electrician was there first, then the furnace installer has a problem in that he must provide a walkway as stated in the posts. So far as derating, the cable used is NMB based on the color of the jacket, and is AWG #12. The ampacity is 30 amperes, and the derating for up to 24 conductors is 70% or 21 Amperes for a residential occupancy with 50% allowed diversity. Based on the information available to us, I would hesitate to condemn the installation for spacing and derating. The walkway issue and protection is another issue that must be addressed. This is why the NFPA has an AHJ, one AHJ might allow something that another would condemn out of hand.

Originally Posted by Ted Menelly

If this were your inspection or if your were consulted to as what would make this situation right, what would you advise.

Ted,

I would tell my client that the easiest way to address this would likely be to space the NM cables out where they cross the plywood walkway, staple them to the plywood, then install 2 (possibly 3) 2x4s across the walkway, one before the first NM cable, one next to the truss after the last NM cable, and, if needed because the NM cables take of too much of the walkway, one in the middle between the NM cables. laying a piece of plywood across the top of the 2x4s. The 2x4s plus 1/2" plywood make the minimum required 4" riser.

If the NM cables are spaced out, that deals with the derating, now you are down to making a simple bridge over the NM cables to keep workers off them. Protection from physical damage.

Easy to do and does not cost much for either material or labor.

Originally Posted by Nathaniel Johnson

If this is new construction, then the contractor has a problem in that the electrician installed his wiring on the walkway. If the electrician was there first, then the furnace installer has a problem in that he must provide a walkway as stated in the posts.

Nathaniel,

While the above is true as to who had the problem at a given stage during construction, the person who now has the problem is the electrician. He needs to correct and protect his wiring.

So far as derating, the cable used is NMB based on the color of the jacket, and is AWG #12. The ampacity is 30 amperes, and the derating for up to 24 conductors is 70% or 21 Amperes for a residential occupancy with 50% allowed diversity.

Let's stop there before continuing.

The #12 AWG NMB conductors have insulation rated for 90 degrees C for derating purposes, not for overcurrent protection purposes.

The NMB conductors, rated for 30 amps for derating purposes, are derated for ambient (I am using 132-140 degrees F as many attics reach 130+ in the summer), based on Table 310.16, Correction Factors, 0.71, or, 71% of the derating rating of 30 amps. 30 amps x 0.71 = 21.3 amps derated for ambient.

The next derating to be applied is for bundling/lack of maintaining space.

From Table 310.15(B)(2)(a), using 8-10 12-2 NMB cables, making for 16-20 conductors, the derating factor is 50%. 21.3 amps x 50% = 10.65 amps. Which is what I posted previously.

Even if we apply your 70% instead of the 50% from the table, the following derating is required: 21.3 x 70% = 14.91. That means those 12-2 NMB circuits are derated to 15 amp circuits.

Now matter how you run the math, those are required to be derated and are no longer 20 amp circuits.

Based on the information available to us, I would hesitate to condemn the installation for spacing and derating.

You would, I would not, the code does not.

The walkway issue and protection is another issue that must be addressed.

The two issues are not mutually exclusive. The NM cables *can be* fanned out to maintain the required spacing, *and*, the walkway can be addressed (see above post to Ted) without negatively affecting the NM cables.

This is why the NFPA has an AHJ,

The reason the NFPA has an AHJ is to enforce what the code states (when stated as clearly as this issue is stated) and to make interpretations for when it is not. The AHJ is not there to try to reduce the code so as to make allowances for something else done incorrectly.

I was hoping you would have stated what you were: home inspector, code inspector, electrician, etc., as you sound knowledgeable on code and would be able to provide for good information to us.

Thank you for your response.

Thanks Jerry

From what I could see in the photos and by guessing how large the wires are and, and, and a bunch of ands, I more than likely would have said something along those lines and in the end I most certainly would have advised them to have an electrician evaluate the concerns for my findings before taking any further steps.

I try to maintain the generalist point of view to my clients. If I get deeper into evaluation than that it takes me away from the generalist and puts me into the specialist, technically exhaustive field. Everything I tell my clients and have them read and or sign explains to them that we find concerns and a specialist in that particular field should evaluate the concerns.

Thanks for your opinion

Ted