NEC 376.22 Question

[FelixZn]

Regarding NEC 376.22 Number of Conductors and Ampacity, which states:

"(A) Cross-Sectional Areas of Wireway.
The sum of the cross-sectional areas of all contained conductors and cables at any cross section of a wireway shall not exceed 20 percent of the interior cross-sectional area of the wireway."

When they say "cross-sectional areas of all contained conductors and cables", does this includes the conductor insulation or just the area of the conductor itself?

 

[infinity]

Fill considers the overall dimension of the conductor.

 

[LarryFine]

Welcome to the forum.

It's all about heat generation and dissipation, so it's total area = air space area + conductor area.

 

[infinity]

Welcome to the forum.

It's all about heat generation and dissipation, so it's total area = air space area + conductor area.

Is the 20% actually about heat disapation or a safe fill limit so that the conductors are not damaged during installation?

 

[LarryFine]

Is the 20% actually about heat disapation or a safe fill limit so that the conductors are not damaged during installation?

Conduits are 40%, and I don't see why a wireway would be worse. But I don't really know for sure.

 

[FelixZn]

Welcome to the forum.

It's all about heat generation and dissipation, so it's total area = air space area + conductor area.

Thanks for your answer and the welcome!