Conduit Fill

[Mark59]

Wht is the basis for the % counduit fill table 1 chapter 9?

 

[dcspector]

Damage to conductors when pulling and heat. There is even a jam ratio.

 

[Rockyd]

Read the FPN's to the table?

 

[raider1]

Read the FPN's to the table?

To add to what Rockyd posted I will paste the FPN's from Table 1 of Chapter 9.

FPN No. 1: Table 1 is based on common conditions of proper cabling and alignment of conductors where the length of the pull and the number of bends are within reasonable limits. It should be recognized that, for certain conditions, a larger size conduit or a lesser conduit fill should be considered.
FPN No. 2: When pulling three conductors or cables into a raceway, if the ratio of the raceway (inside diameter) to the conductor or cable (outside diameter) is between 2.8 and 3.2, jamming can occur. While jamming can occur when pulling four or more conductors or cables into a raceway, the probability is very low.

Chris

 

[don_resqcapt19]

Damage to conductors when pulling and heat. There is even a jam ratio.

Greg,
I don't think that the heat has anything to do with the conduit fill. That issue is addressed with the adjustment factors in 310.15(B)(2). The fill is just physical protection for the conductors when they are being installed.

 

[dcspector]

Thanks Don I just threw out a bunch of general comments.