Bundled = Derated

[websparky]

Here is a practice I see all to often. They run the lenghth of the basement. Each one is 48" minimum before any drop off.

Bottom line, after three CCC's we have to derate. In this case the installer has to remove the extras and reroute them in other holes.

Agreed?

 

[iwire]

Re: Bundled = Derated

Dave here in MA many inspectors agree with you about this being bundling, I do too.

One note though is that with 15, 20 and 30 amp circuits using 14, 12 and 10 AWG CU the derating is not an issue until the 10th current carrying conductor.

12 AWG rated @ 30 amps

7 - 9 conductors gets a 70% reduction

30 * .7 = 21 amps.

Once you move beyond the 14, 12, and 10 the issue comes up with less conductors. But then again we really do not have bundles of 8 AWG and larger NMs.

So what I would say is in general four - 2 or 3 wire cables is the most you can run through together.

[ September 18, 2005, 01:31 PM: Message edited by: iwire ]

 

[pierre]

Re: Bundled = Derated

I would need a lot of convincing for anyone to tell me this is bundling - of which is not defined in the NEC.

Take a look at the "spacing" of some of the cables between the framing members. Heat has a chance to dissipate? YES or NO?

 

[macmikeman]

Re: Bundled = Derated

Most of those 12-2 cables are run to outlets that see very little use at all anyway. This installer made 4 holes for his power runs, and spread out his wiring. To me this ain't bundling. Put all the wiring in one hole and ty wrap or tape it up in a spiral wrap and you have bundling. Or we could do this like San Fran and make 28 holes here in the joist, and run only one cable in each. Nobody on this fourm has been able to offer any substantial proof that an installation such as the one in the picture has ever caused any fire.

 

[bphgravity]

Re: Bundled = Derated

Using the definition of "bundled" in Article 520, which I have proposed to be moved to Article 100, the picture does not appear to be bundling, unless you consider "periodically bound together" the same as running through bored holes, which I do not.

 

[LarryFine]

Re: Bundled = Derated

Originally posted by bphgravity:
Using the definition of "bundled" in Article 520, which I have proposed to be moved to Article 100, the picture does not appear to be bundling, unless you consider "periodically bound together" the same as running through bored holes, which I do not.

Well, it would be difficult to consider run through a hole every 16" anything other than "periodically bound together". Of course, I'm in favor of allowing it. :roll:

 

[jim k]

Re: Bundled = Derated

Aside from the bundling issue, what do you think about the coaxial cable(s) run directly alongside the NM?

- Jim K

 

[sparky_magoo]

Re: Bundled = Derated

I think the coaxial cables run parallel to NM with in two feet of each other is completely unacceptable.

 

[sparky_magoo]

Re: Bundled = Derated

I frequently see all of the NM cables rising out of a panelboard neatly ty-wrapped into one large bundle. The bundle will travel through the joists in the garage and individual cables will branch out from the bundle as reqiured. IMO, this de-rates the conductors at least fifty percent depending on how many home runs are present. I have questioned fellow RSM's about this practice and have been told I don't know what I am talking about.

 

[iwire]

Re: Bundled = Derated

Originally posted by sparky_magoo:
I think the coaxial cables run parallel to NM with in two feet of each other is completely unacceptable.

820.52(A)(2) Other Applications. Coaxial cable shall be separated at least 50 mm (2 in.) from conductors of any electric light, power, Class 1, non?power-limited fire alarm, or medium power network-powered broadband communications circuits.

 

[sparky_magoo]

Re: Bundled = Derated

Keeping coax seperated from power cables isn't a safety issue. The purpose is prevent noise from being induced onto the shield of the coax. 60hz noise is frequently manifested as "hum bars" rolling down the picture tube. It can also induce 60hz hum into the audio.

 

[infinity]

Re: Bundled = Derated

Coaxial cable shall be separated at least 50 mm (2 in.) from conductors of any electric light, power, Class 1, non?power-limited fire alarm, or medium power network-powered broadband communications circuits.

I would argue that conductors and cables are not the same thing.

 

[leggo]

Re: Bundled = Derated

websparky,
Was this a picture looking up at the ceiling from the basement floor? If so, they should use a product called speedway. It allows you to put all those cables into a troff like raceway with a plastic cover and an open top for heat dissipation.
Leggo

 

[George Stolz]

Re: Bundled = Derated

I agree with Pierre, this isn't bundling, IMO.

The coax running with the power is pretty lazy. Doesn't take much to just get them in their own holes.

 

[infinity]

Re: Bundled = Derated

Was this a picture looking up at the ceiling from the basement floor? If so, they should use a product called speedway

What would be the advantage of using Speedway?

 

[tom25]

Re: Bundled = Derated

I also agree with Pierre.
I have seen a test with 21-14/2 cables, and 6 - 12/2 cables installed in a 1-1/4" bored hole packed really tight.
The 14/2 cables had 12 amps on every conductor while the 12/2 cables had 16 amps on every conductor. Ambient temperature was 75 degrees F.
had 4 thermocouples installed ran for 4 hours with the load, and the hottest temperature was in the center of the cables in the middle of the hole.
Hottest temperature was 189.8 degrees F.
I would not be concerned in a single family dwelling.
I would be more concerned with the sheathing of the cables being damaged by pulling them through the holes.

 

[charlie b]

Re: Bundled = Derated

Let me submit for your consideration the following views:
</font>

• <font size="2" face="Verdana, Helvetica, sans-serif">These are not bundled, as there is no single place in which they travel 24 inches or more through a single hole.</font>

<font size="2" face="Verdana, Helvetica, sans-serif"></font>

• <font size="2" face="Verdana, Helvetica, sans-serif">They are also not in conduit, cable, or raceway. So neither Table 310.16 nor Table 310.15(B)(2)(a) apply.</font>

<font size="2" face="Verdana, Helvetica, sans-serif"></font>

• <font size="2" face="Verdana, Helvetica, sans-serif">Rather, they are in "free air," and Table 310.17 applies. So the ampacity of a #12 THHN is 40 amps, though 240.4(D) still limits us to use of a 20 amp breaker.</font>

<font size="2" face="Verdana, Helvetica, sans-serif"> Whatcha tink?

 

[pierre]

Re: Bundled = Derated

George
It is not often that you completely agree with me .

820.52(A)
(2) Other Applications. Coaxial cable shall be separated at least 50 mm (2 in.) from conductors of any electric light, power, Class 1, non?power-limited fire alarm, or medium power network-powered broadband communications circuits.

Exception No. 1: Where either (1) all of the conductors of electric light, power, Class 1, non?power-limited fire alarm, and medium power network-powered broadband communications
and circuits are in a raceway, or in metal-sheathed, metal-clad, nonmetallic-sheathed Type AC or Type UF cables, or (2) all of the coaxial cables are encased in raceway.

Exception No. 2: Where the coaxial cables are permanently separated from the conductors of electric light, power, Class 1, non?power-limited fire alarm, and medium power network-powered broadband communications circuits
by a continuous and firmly fixed nonconductor, such as porcelain tubes or flexible tubing, in addition to the insulation on the wire.

This permits those cables to be installed in the same bored hole as NM, AC cables, etc....


From Bryan
Using the definition of "bundled" in Article 520, which I have proposed to be moved to Article 100, the picture does not appear to be bundling, unless you consider "periodically bound together" the same as running through bored holes, which I do not.


From CMP in the '05 Report on Proposals.

1-67 Log # 1601 NEC-P01
(100-Bundled (New)) Final Action: Reject

Panel Statement:
The definition belongs in Article 520. Its use in Article 310 is largely unrelated to the Article 520 definiton.


I am not too sure I understand or agree with the reasoning ?

 

[pierre]

Re: Bundled = Derated

From Charley
Rather, they are in "free air," and Table 310.17 applies. So the ampacity of a #12 THHN is 40 amps, though 240.4(D) still limits us to use of a 20 amp breaker.
Whatcha tink?

Table 310.17 is for single-insulated conductors, not conductors in a sheathing such as NM Cable.

 

[charlie b]

Re: Bundled = Derated

Originally posted by pierre:Table 310.17 is for single-insulated conductors, not conductors in a sheathing such as NM Cable.

Snapping my fingers and saying "aw shucks."

By the way, who is "Charley"?

Charlie B.