george t. everett
Senior Member
- Location
- New York
Are cables that are run thru holes in wood I-joists that are 16" centers, considered bundling?
Bundling cables
- Thread starter george t. everett
- Start date
- Status
mikeames
Senior Member
- Location
- Gaithersburg MD
- Occupation
- Teacher - Master Electrician - 2017 NEC
Re: Bundling cables
No
No
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: Bundling cables
NEC 2002 310.15 (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 stacked or bundled longer than 600 mm (24 in.) without maintaining spacing and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a).
NEC 2002 310.15 (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 stacked or bundled longer than 600 mm (24 in.) without maintaining spacing and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a).
russellroberts
Senior Member
- Location
- Georgia
Re: Bundling cables
If we use the 90 deg.C column in 310.16 does this not give you some leeway? Or am I way off?
Otherwise, it seems that 1 or 2 12-2's would be max in say a 1" hole.
Russell
If we use the 90 deg.C column in 310.16 does this not give you some leeway? Or am I way off?
Otherwise, it seems that 1 or 2 12-2's would be max in say a 1" hole.
Russell
gregoryelectricinc
Senior Member
Re: Bundling cables
Rssell, In our area we have to keep it to 6 or less current carrying cond's per hole. Using the 90 deg. column for derating this keeeps you within NEC limits
Rssell, In our area we have to keep it to 6 or less current carrying cond's per hole. Using the 90 deg. column for derating this keeeps you within NEC limits
russellroberts
Senior Member
- Location
- Georgia
Re: Bundling cables
Greg, although I'm not inspected in my home county,thats what I have understood it to mean.
And where I am inspected,3 12-2's is what they allow in a 1" hole. And it makes sense from another perspective too. If you try to pull more than that in and you're going any distance,you've got no jacket left.
Russell
Greg, although I'm not inspected in my home county,thats what I have understood it to mean.
And where I am inspected,3 12-2's is what they allow in a 1" hole. And it makes sense from another perspective too. If you try to pull more than that in and you're going any distance,you've got no jacket left.
Russell
Re: Bundling cables
I can understand the reason for limiting the number of 12/2 to 3 or 4 per 1 inch hole, because of damaging the cable. But i don't think there would be any ampacity adjustment needed. That adjustment factor as sparky quoted states bundled for more than 24 inches.
Unless you are using the I joists on their sides it is haerd to imagine 1 24 inches thick
I can understand the reason for limiting the number of 12/2 to 3 or 4 per 1 inch hole, because of damaging the cable. But i don't think there would be any ampacity adjustment needed. That adjustment factor as sparky quoted states bundled for more than 24 inches.
Unless you are using the I joists on their sides it is haerd to imagine 1 24 inches thickwebsparky
Senior Member
- Location
- Cleveland, Ohio
Re: Bundling cables
If your joists are spaced 16" o.c., and you have 6 12/3-WG cable, you would have 12 current carring conductors. If this method is run through 3 or more joist, you will have 32" of bundling. Anything after 24" requires derating.
If your joists are spaced 16" o.c., and you have 6 12/3-WG cable, you would have 12 current carring conductors. If this method is run through 3 or more joist, you will have 32" of bundling. Anything after 24" requires derating.
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