tim89s
Member
- Location
- Brush Prairie WA
What code section states how many cables you can run through metal studs? As a rule I will only run two cables, three at the absolute max.
cables through metal studs
- Thread starter tim89s
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- Location
- Massachusetts
Re: cables through metal studs
There is not a maximum amount of cables exactly.
There is a maximum number of current carrying conductors you can bundle before you have to derate.
For 14 AWG and 12 AWG NM cables you can have 9 current carrying conductors bundled as long as you want.
Go up to 10 current carrying conductors and the derating will likely be enough to make 14 AWG unusable on a 15 amp breaker and 12 AWG would need to be on a 15 amp breaker.
As always this is not an absolute, temperature and the type of circuit can effect this figure.
Also you can bundle as many as you want for distances of less than 24"
Some will say running sideways through the same holes in studs is not bundling but I have not found inspectors feel the same way.
There is not a maximum amount of cables exactly.
There is a maximum number of current carrying conductors you can bundle before you have to derate.
For 14 AWG and 12 AWG NM cables you can have 9 current carrying conductors bundled as long as you want.
Go up to 10 current carrying conductors and the derating will likely be enough to make 14 AWG unusable on a 15 amp breaker and 12 AWG would need to be on a 15 amp breaker.
As always this is not an absolute, temperature and the type of circuit can effect this figure.
Also you can bundle as many as you want for distances of less than 24"
Some will say running sideways through the same holes in studs is not bundling but I have not found inspectors feel the same way.
A
a.wayne3@verizon.net
Guest
Re: cables through metal studs
Bob where did you find the 9 conductor rating,I have an inspector that says no more than 2 nm under 1 staple after that use stackers he says its bundling to use a seu staple and lets say 2 12/2 and a 12/3
Bob where did you find the 9 conductor rating,I have an inspector that says no more than 2 nm under 1 staple after that use stackers he says its bundling to use a seu staple and lets say 2 12/2 and a 12/3
- Location
- Massachusetts
Re: cables through metal studs
Allen I think I have learned not to comment on Florida procedures.
As for the staples that could be a staple listing issue.
As for the 9 current carrying conductors.
We are allowed to start with the 90C column of 310.16 for derating NM.
Table 310.16 lists 12 AWG @ 90c 30 amps.
Table 310.15(B)(2)(a) shows a 70% adjustment for 7-9 current carrying conductors.
30 amps x .7 = 21 amps, so we can still use a 20 amp breaker.
Move to 10 current carrying conductors and we get to 50% adjustment
30 x .5 = 15 so 12 AWG would now need to be on a 15 amp breaker.
There will be 2 current carrying conductors in most dwelling unit NMs 2 wire or 3 wire.
That said you should be able to bundle 4 NM cables as much as you want.
Move to 12 AWG MC and you can bundle much more because of an exception.
Bob
[ January 03, 2004, 11:12 AM: Message edited by: iwire ]
Allen I think I have learned not to comment on Florida procedures.
As for the staples that could be a staple listing issue.
As for the 9 current carrying conductors.
We are allowed to start with the 90C column of 310.16 for derating NM.
Table 310.16 lists 12 AWG @ 90c 30 amps.
Table 310.15(B)(2)(a) shows a 70% adjustment for 7-9 current carrying conductors.
30 amps x .7 = 21 amps, so we can still use a 20 amp breaker.
Move to 10 current carrying conductors and we get to 50% adjustment
30 x .5 = 15 so 12 AWG would now need to be on a 15 amp breaker.
There will be 2 current carrying conductors in most dwelling unit NMs 2 wire or 3 wire.
That said you should be able to bundle 4 NM cables as much as you want.
Move to 12 AWG MC and you can bundle much more because of an exception.
Bob
[ January 03, 2004, 11:12 AM: Message edited by: iwire ]
jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: cables through metal studs
Allen which inspector came up with that one?They got pissed if had 2 rows and they were saying use 1 large staple and stay in the middle.How can they call it bundling if after the staple they seperat some?We are allowed 24 inches
Allen which inspector came up with that one?They got pissed if had 2 rows and they were saying use 1 large staple and stay in the middle.How can they call it bundling if after the staple they seperat some?We are allowed 24 inches
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: cables through metal studs
Allen I think the requirment of useing stackers after 2 cables under a staple is more for staying in the middle of the studs not for bundling. As with two rows of cable running down a stud you will not be able to maintain 1.25" from the edge. as found in 300.4(A)(1). As for a inspector call cables running through holes in stud's bundling? how can they! as the cable's are not kept tight together more than 24" as required in 315.15(B)(2)
Allen I think the requirment of useing stackers after 2 cables under a staple is more for staying in the middle of the studs not for bundling. As with two rows of cable running down a stud you will not be able to maintain 1.25" from the edge. as found in 300.4(A)(1). As for a inspector call cables running through holes in stud's bundling? how can they! as the cable's are not kept tight together more than 24" as required in 315.15(B)(2)
A
a.wayne3@verizon.net
Guest
Re: cables through metal studs
Jim it was (edited to remove name reference).He is just being well anal if I can say that here.Hurk it is a matter of 1 1/4 clearance that arises out of not being able to stack 2 pieces of nm under one staple.I contend that it is ok and wanted to have a code referance to stand by.As far as not wanting to comment on Florida procedures you will probably save a lot of hair pulling These guys have their own agenda they go by and it is so frustrating.In one breath they cite articles in the Nec and in the next they put their own spin on it.So what to do ??? Well I for one stand fats that if it is in the NEC and there are no local addendums we have notified of then the NEC stands
[ January 04, 2004, 06:26 PM: Message edited by: don_resqcapt19 ]
Jim it was (edited to remove name reference).He is just being well anal if I can say that here.Hurk it is a matter of 1 1/4 clearance that arises out of not being able to stack 2 pieces of nm under one staple.I contend that it is ok and wanted to have a code referance to stand by.As far as not wanting to comment on Florida procedures you will probably save a lot of hair pulling
These guys have their own agenda they go by and it is so frustrating.In one breath they cite articles in the Nec and in the next they put their own spin on it.So what to do ??? Well I for one stand fats that if it is in the NEC and there are no local addendums we have notified of then the NEC stands[ January 04, 2004, 06:26 PM: Message edited by: don_resqcapt19 ]
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