Conduit Sizing

[Mike01]

looking at chapter 9 tables for raceway and conductor properties to as it relates to conduit fill it appears that the tables approximate area for the associated cable size & insulation appear to be slightly larger than some industry product specification sheets. If the tables are used one conduit size is required (usually larger) if the manufacturer product literature the conduit used it may be smaller. On the manufactuer data sheet it inidcates diameters to be nominal and subject to industry tolerances, is this why the NEC has a larger approximate area? Should the NEC tables be used or the product data sheets?

 

[jumper]

Should the NEC tables be used or the product data sheets?

I would say the tables.

 

[iwire]

The NEC without a doubt.

But truthfully the conduit fill tables in the back of the code book are not code.

The only true way to make sure you comply is to do the fill calculations yourself.

 

[fmtjfw]

If you are planning to pull the cable, use the NEC
If someone else is pulling the cable, use the manufacturer's recmmmendation:happysad:

 

[iwire]

If you are planning to pull the cable, use the NEC
If someone else is pulling the cable, use the manufacturer's recmmmendation:happysad:

I might add that if you are pulling go one size bigger than NEC.

 

[jumper]

The NEC without a doubt.

But truthfully the conduit fill tables in the back of the code book are not code.

The only true way to make sure you comply is to do the fill calculations yourself.

Just to clarify: you are referring to Annex C tables as not being code and not Chapter 9 tables, correct?

 

[iwire]

Just to clarify: you are referring to Annex C tables as not being code and not Chapter 9 tables, correct?

Yes, they are the only ones called conduit fill.

 

[don_resqcapt19]

Note 5 to Table 1 in Chapter 9, stongly implies that you do the conduit fill calculations based on the wire deminsions given in Chaper 9, Tables 5 and 5a.