Conduit fill rates

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wa5yom

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How would I determine the conduit fill rate for type NM wire.....specifically 12/2 and 14/2 in 2 in rigid conduit?
 
infinity

infinity

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You need to calculate as if the cable were round:

Chapter 9
Table 1 Percent of Cross Section of Conduit and Tubing for Conductors
Note(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.
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Keep in mind that derating will apply if the raceway is longer than 24".
 
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wa5yom

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I am upgrading the service...and the box is outside....2 in conduits will come out of the top of the box then enter the house through LB's......
I will use the2 in conduits to reduce the amount of entrances into the house....

So, I am looking for a table that tells me how many nm conductors (based on ga.) can be feed through conduit...in this case it is schedule 80....

Thanks.....for any help you can provide.
 
roger

roger

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You have another problem, the NM can not be installed in these conduits outside.


Roger
 
infinity

infinity

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An maybe another problem, it's unlikely that you can maintain the required 5X bending radius when going through an LB conduit body.

334.24 Bending Radius.
Bends in Types NM, NMC, and NMS cable shall be so made that the cable will not be damaged. The radius of the curve of the inner edge of any bend during or after installation shall not be less than five times the diameter of the cable.
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