I'm hooking up a row of modular townhomes. The circuits drop out of the floor to basement in a bundle, then must go about 30' to get to the panel. I cut the zip ties off, pulled through a couple framing memebers to get there. The inspector thinks this is bundling and I don't.Opinions??
Romex bundling clarification
- Thread starter D.Rater
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allenwayne
Senior Member
Re: Romex bundling clarification
Bundling can be cited when there are 9 or more current carrying conductors that are run together for 24 ins or more.So if the framing members are 2 ft apart and you run the NM from member to member together the ahj is correct.
Bundling can be cited when there are 9 or more current carrying conductors that are run together for 24 ins or more.So if the framing members are 2 ft apart and you run the NM from member to member together the ahj is correct.
macmikeman
Senior Member
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- Planet macmikeman
Re: Romex bundling clarification
Look at 310.15 (B) (2). Key word here is maintain spacing. Some inspectors will allow it if you fan out the cables between joists, but then you are not really "maintaining" the spacing because you are grouping them again where they pass thru each flooring member. So to be in complete compliance you need to drill more holes and be sure to "maintain spacing". In reality since these are dwellings we are talking about, there really not much possibility of a danger from heat dissapation, but code is code.
Look at 310.15 (B) (2). Key word here is maintain spacing. Some inspectors will allow it if you fan out the cables between joists, but then you are not really "maintaining" the spacing because you are grouping them again where they pass thru each flooring member. So to be in complete compliance you need to drill more holes and be sure to "maintain spacing". In reality since these are dwellings we are talking about, there really not much possibility of a danger from heat dissapation, but code is code.
bphgravity
Senior Member
- Location
- Florida
Re: Romex bundling clarification
I don't consider anything to be "bundled" unless they are physically tied, wrapped, taped, or otherwise periodically bound together. I base this on the definition in Article 520 which I believe should be in Article 100.
I don't consider anything to be "bundled" unless they are physically tied, wrapped, taped, or otherwise periodically bound together. I base this on the definition in Article 520 which I believe should be in Article 100.
Re: Romex bundling clarification
I think that it can be argued that passing the conductors through holes in framing members does periodically bind the conductors together. Does it make any difference to the conductors whether it is a ring of plastic (zip tie) every 24" or a ring of wood (the framing member) that is binding them together? But, there are a couple of things to look at:
1) How much of the run can be considered to be bundled? If it is less than 10' or 10% of the total run (which ever is less), The exception to 310.15(2) allows you to ignor the lower ampacity of the derated section.
2) How many current carrying conductors are in the bundle? For #12 on a 20 amp breaker, you would need more than 9 for derating to be important since 70% of the 90? ampacity (30 amps) is 21 amps. The same is true of #14 on a 15 amp breaker since 70% of 25 amps is 17.5 amps.
I think that it can be argued that passing the conductors through holes in framing members does periodically bind the conductors together. Does it make any difference to the conductors whether it is a ring of plastic (zip tie) every 24" or a ring of wood (the framing member) that is binding them together? But, there are a couple of things to look at:
1) How much of the run can be considered to be bundled? If it is less than 10' or 10% of the total run (which ever is less), The exception to 310.15(2) allows you to ignor the lower ampacity of the derated section.
2) How many current carrying conductors are in the bundle? For #12 on a 20 amp breaker, you would need more than 9 for derating to be important since 70% of the 90? ampacity (30 amps) is 21 amps. The same is true of #14 on a 15 amp breaker since 70% of 25 amps is 17.5 amps.
bassphisher
Member
Re: Romex bundling clarification
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 (140?F) 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 bundled together and pass through wood framing that is to be fire- or draft-stopped using thermal insulation or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).
Pay attention to the second paragraph
[ January 09, 2006, 05:13 PM: Message edited by: bassphisher ]
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 (140?F) 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 bundled together and pass through wood framing that is to be fire- or draft-stopped using thermal insulation or sealing foam, the allowable ampacity of each conductor shall be adjusted in accordance with Table 310.15(B)(2)(a).
Pay attention to the second paragraph
[ January 09, 2006, 05:13 PM: Message edited by: bassphisher ]
allenwayne
Senior Member
Re: Romex bundling clarification
Bryan please come here to inspect.Our inspectors look for bundling .Find 5 2 wires stapled up a stud an instant tag.I have never had a problem with call backs but there must be a bonafide reason for the article to say it.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Romex bundling clarification
For most applications, bunding of NM cable is not an issue.
First of all the ampacity of 12-2 NMB is 30 amperes, not 20 (334.80), you derate from 30 amperes and as long as the adjusted ampacity does not exceed 20 amperes per 240.4(D) then you are fine.
Ask you AHJ what the ampacity of 12-2 NMB is. If he says 20 amperes, have him review 334.80, and remove his red-tag.
For most applications, bunding of NM cable is not an issue.
First of all the ampacity of 12-2 NMB is 30 amperes, not 20 (334.80), you derate from 30 amperes and as long as the adjusted ampacity does not exceed 20 amperes per 240.4(D) then you are fine.
Ask you AHJ what the ampacity of 12-2 NMB is. If he says 20 amperes, have him review 334.80, and remove his red-tag.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Re: Romex bundling clarification
Except for the pass through the bottom plate of the first floor, this doesn't seem to apply here.
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