Some pics to talk about

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jaxbldginspector

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Romex 10/2 w/g
Romex 10/3 w/g
Romex 12/2 w/g
Romex 12/3 w/g
 

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CodeOne

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How do you figure? What would you consider "maintaining spacing"?

May be bundling in the sense you are used to is not the correct term I should use. However it would have to be derated per 2008. I personally would still say it is bundled for derating purposes there is no spacing between those conductors and would not pass the job. See below note last two paragraphs.

334.80 Ampacity. The ampacity of Types NM, NMC, and
NMS cable shall be determined in accordance with 310.15.
The ampacity shall be in accordance with the 60°C (140°F)
conductor temperature rating. The 90°C (194°F) rating
shall be permitted to be used for ampacity derating purposes,
provided the final derated ampacity does not exceed
that for a 60°C (1400 P) rated conductor. The ampacity of
Types NM, NMC, and NMS cable installed in cable tray
shall be determined in accordance with 392.11.

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

Where more than two NM cables containing two or more
current-carrying conductors are installed in contact with thermal
insulation without maintaining spacing between cables the
allowable ampacity of each conductor shall be adjusted in
accordance with Table 310.15(B)(2)(a)
 

Speedy Petey

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See below note last two paragraphs.
These cables are neither:

"through the same
opening in wood framing that is to be fire- or draft-stopped
using thermal insulation, caulk, or sealing foam,"


Nor are they:

"installed in contact with thermal
insulation"
.

So the last two paragraphs do not apply.

If they were, or are to be, then the last two paragraphs apply.
 

CodeOne

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These cables are neither:

"through the same
opening in wood framing that is to be fire- or draft-stopped
using thermal insulation, caulk, or sealing foam,"


If they were, or are to be, then the last two paragraphs apply.

These cables are going through the draft stopping band of the floor joist as per the building code.
Requiring the holes to be sealed.
 
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CodeOne

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R502.12 Draftstopping required. When there is usable space
both above and be low the concealed space of a floor/ceiling as -
sembly, draftstops shall be in stalled so that the area of the con
-cealed space does not exceed 1,000 square feet (92.9 m2).
Draftstopping shall divide the concealed space into approxi -
mately equal areas. Where the assembly is enclosed by a floor
membrane above and a ceiling membrane below draftstopping
shall be provided in floor/ceiling assemblies under the fol low -
ing circumstances:
1. Ceiling is suspended under the floor framing.
2. Floor framing is constructed of truss-type open-web or
perforated members.

R502.12.1 Materials. Draftstopping materials shall not be less
than 1/2-inch (12.7 mm) gypsum board, 3/8-inch (9.5 mm) wood
structural panels, 3/8-inch (9.5 mm) Type 2-M-W particleboard
or other approved materials adequately supported.
Draftstopping shall be in stalled parallel to the floor framing
members unless other wise approved by the building of ficial.
The integrity of all draftstops shall be maintained

R502.13 Fireblocking required. Fireblocking shall be pro -
vided in wood-frame floor construction and floor-ceiling as -
semblies in accordance with Section R602.8.

R602.8 Fireblocking re quired. Fireblocking shall be pro -
vided to cut off all concealed draft openings (both vertical and
horizontal) and to form an effective fire barrier between sto -
ries, and between a top story and the roof space. Fireblocking
shall be provided in wood-frame construction in the following
locations.
1. In concealed spaces of stud walls and partitions, includ -
ing furred spaces and parallel rows of studs or staggered
studs; as follows:
1.1. Vertically at the ceiling and floor levels.
1.2. Horizontally at intervals not exceeding 10 feet
(3048 mm).
2. At all interconnections between concealed vertical and
horizontal spaces such as occur at soffits, drop ceilings
and cove ceilings.
3. In concealed spaces be tween stair stringers at the top and
bot tom of the run. En closed spaces under stairs shall
com ply with Section R311.2.2.
4. At openings around vents, pipes, and ducts at ceiling and
floor level, with an approved material to resist the free
pas sage of flame and products of combustion.
5. For the fireblocking of chimneys and fire places, see Sec -
tion R1001.16.
6. Fireblocking of cornices of a two-family dwelling is re -
quired at the line of dwelling unit separation.
 
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CodeOne

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Please note these references are from the 2006 NC Residential Building code based on the 2002 ICC Residential Codes.
 
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CodeOne

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Also if this is a basement thats not going to be finished at this time without a heating system it could be required to be insulated. Then you would have to derate for the thermal insulation also. Another possibility is insulating for sound control also would need to be derated.
 

CodeOne

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According to 310.15(B)(2)(a) more than 41 current carrying conductors have to be derated by 35% Which means you could not even put a 15A breaker on those #10's. in the first picture on the left if I counted correctly. Hard to see actually how many conductors are there.
 

TedL

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According to 310.15(B)(2)(a) more than 41 current carrying conductors have to be derated by 35% Which means you could not even put a 15A breaker on those #10's. in the first picture on the left if I counted correctly. Hard to see actually how many conductors are there.

Sounds like some bad math.#10 would be 30 amp without derating. 30x.65=19.5 amps, which would allow a 20 amp breaker.
 

Speedy Petey

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You do not derate from the 30A figure. You use the actual temperature rating of the wire, which is the 90 deg C column for new THHN conductor NM cable.

#10 NM cable is derated from 40 amps. And you do not derate by 35%. You derate TO 35%.
Even at a 35% adjustment you CAN use a 15A breaker since we round UP to the nearest standard breaker size.
40 x 35% = 14A = 15A breaker
 

CodeOne

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15A breaker since we round UP to the nearest standard breaker size.
40 x 35% = 14A = 15A breaker

Thanks Speedy Petey that rounding up rule is one I forget once in a while.:eek:

Still the caculation does come out to less than 15A. I still say the wiring routes taken are very bad practice.
 

TedL

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According to 310.15(B)(2)(a) more than 41 current carrying conductors have to be derated by 35% Which means you could not even put a 15A breaker on those #10's. in the first picture on the left if I counted correctly. Hard to see actually how many conductors are there.

I didn't dig out my copy of the code, but took Codeone's statement "by 35%" at face value. I just did the math check.

I did remember the "next larger standard overcurrent device"
:D.
 

CodeOne

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Just for debate we need to look at Article 334.80 of the NEC . Looks like it rules out the next highest breaker with two words.

334.80 Ampadty. The ampacity of Types NM, NMC, and
NMS cable shall be determined in accordance with 310.15.
The ampacity shall be in accordance with the 60°C (140°F)
conductor temperature rating. The 90°C (194°F) rating
SHALL be permitted to be used for ampacity derating purposes,
PROVIDED the final derated ampacity does not exceed
that for a 60°C (1400 P) rated conductor. The ampacity of
Types NM, NMC, and NMS cable installed in cable tray
shall be determined in accordance with 392.11


Now I'm not saying some AHJ's dont allow this, however it is something to consider. It may be just bad wording to give the intent. That happens sometimes.
 
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