Conduit filll based on procured vs NEC chapter 9

[liverpool]

If I have cut sheets of the procured cables and conduit, would I be able to use the published data in lieu of the NEC chapter 9 tables? The NEC tables are conservative and in some cases I can fit more cables within a 40% fill.

 

[infinity]

The chapter 9 tables are for informational purposes and not part of the NEC. Your calcuation is what counts. I've read that the tables even have some errors.

 

[don_resqcapt19]

The chapter 9 tables are for informational purposes and not part of the NEC. Your calcuation is what counts. I've read that the tables even have some errors.

The Chapter 9 tables are part of the code. The tables in Annex C are not.

The notes to Table 1 in Chapter 9 strongly imply that you have to use the information in the Chapter 9 tables for your conduit fill calculations. Note 5 says if the conductor is not listed in a Chapter 9 table, then you can use the actual dimensions.

 

[infinity]

The Chapter 9 tables are part of the code. The tables in Annex C are not.

The notes to Table 1 in Chapter 9 strongly imply that you have to use the information in the Chapter 9 tables for your conduit fill calculations. Note 5 says if the conductor is not listed in a Chapter 9 table, then you can use the actual dimensions.

Yes, Don is correct I meant to say the tables in the Annexes not Chapter 9. The last sentence in the OP through me off. :?

The NEC tables are conservative and in some cases I can fit more cables within a 40% fill.

 

[ZinskI/E]

The notes to Table 1 in Chapter 9 strongly imply that you have to use the information in the Chapter 9 tables for your conduit fill calculations. Note 5 says if the conductor is not listed in a Chapter 9 table, then you can use the actual dimensions.

I agree with Don also. What sort of cables are you seeing with such a stark difference between the manufacturer's cross-sectional dimensions and those listed in the tables? With the "rounding" exception provided in Chapter 9 I can't think of an instance where I could have gotten more conductors in a conduit by not using the NEC tables.

 

[liverpool]

It's actually the conduits that appear to have more cross sectional areas than NEC: Galvanized rigid steel, PVC, etc.

 

[don_resqcapt19]

It's actually the conduits that appear to have more cross sectional areas than NEC: Galvanized rigid steel, PVC, etc.

That could be a listing issue. I think that the standards that the conduits are listed to, specify the wall thickness.

 

[don_resqcapt19]

It would be my opinion that the area listed in the Chapter 9 tables is required to be used for the wire fill calculations.