ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

>> Home   >> Electrical-Photos   >> Classifieds   >> Subscribe to Newsletter   >> Store  
 

Photos of the Week:

Meter vs Bricklayer
Meter vs Bricklayer

Advertisement:-Left
Recent Gallery Topics:
What in Tarnation?
What in Tarnation?
by timmp, September 10
Plumber meets Electrician
Plumber meets Electrician
by timmp, September 10
Who's Online Now
0 members (), 32 guests, and 17 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#206304 06/15/12 11:27 AM
Joined: May 2003
Posts: 74
J
jkraft Offline OP
Member
Hello,
Can someone direct me to the NEC section regarding sleeveing romex in conduit for a combination of 12/2 and 14/2, over 10'
thanks,
Joe

Horizontal Ad
Joined: Jul 2004
Posts: 10,006
Likes: 37
G
Member
334.15(B)
Quote
Protection from Physical Damage. Cable shall be protected from physical damage where necessary by rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC conduit, or other approved means. Where passing through a floor, the cable shall be enclosed in rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC conduit, or other approved means extending at least 150 mm (6 in.) above the floor.


Note 9 to table 9 (conduit fill) says
Quote
(9)A multiconductor cable or flexible cord of two or more conductors shall be treated as a single conductor for calculating percentage conduit fill area. For cables that have elliptical cross sections, the cross-sectional area calculation shall be based on using the major diameter of the ellipse as a circle diameter.


two cables can't be stacked and measured, You have to compute for "2 conductors" the size of the widest dimension so you end up with some pretty big pipe.
I haven't run the numbers on a 12 and a 14 but 1" would not surprise me


Greg Fretwell
Joined: May 2003
Posts: 74
J
jkraft Offline OP
Member
thanks for your help Greg, looking at those sections now and trying to determine what size IMC would be needed for 1-12/2 and 2-14/2???

Joined: Jul 2004
Posts: 10,006
Likes: 37
G
Member
OK lets run the numbers
I will use commie metric because I prefer decimals

The 14ga I have measures 9mm, 12ga measures 10mm (across the widest part.

The area is the radius (half the diameter above)squared times pi (3.14)

5 x 5 x 3.14 = 78.5 mm2
4.5 x 4.5 x 3.14 = 63.6 mm2
Total cable area = 142.1 mm2

Take that to table 9 IMC "2 wire" column and you end up with 1" IMC (up to 192 mm2)
3/4 only gives you 117 mm2

See why I wasn't surprised? wink



Greg Fretwell
Joined: Jan 2004
Posts: 1,507
G
Member
Nice answer Greg. Not everyone knows about this approach. Most contractors want to skin the outer jacket from the NM cable and not worry about the rules. A clear violation of 312.5(C)(e).

Last edited by George Little; 06/15/12 10:12 PM.

George Little
Joined: Apr 2002
Posts: 7,411
Likes: 8
Member
Greg:
Ditto with what George said! Nice!!


John

Link Copied to Clipboard
Advertisement:-Right


Tools for Electricians
Tools for Electricians
 

* * * * * * *
2023 National Electrical Code (NEC)
2023 NEC + Exam Prep Study Guides Now Available!
 

Member Spotlight
AllClear
AllClear
Belmond Iowa US
Posts: 44
Joined: August 2005
Top Posters(30 Days)
Popular Topics(Views)
352,167 Are you busy
275,965 Re: Forum
255,509 Need opinion
New Page 2
Powered by UBB.threads™ PHP Forum Software 7.7.5