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NEC 376.22 Question

F

FelixZn

Member
Location
USA
Occupation
Electrical Engineer
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?
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Welcome to the forum.

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

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
LarryFine said:
Welcome to the forum.

It's all about heat generation and dissipation, so it's total area = air space area + conductor area.
Click to expand...
Is the 20% actually about heat disapation or a safe fill limit so that the conductors are not damaged during installation?
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
infinity said:
Is the 20% actually about heat disapation or a safe fill limit so that the conductors are not damaged during installation?
Click to expand...
Conduits are 40%, and I don't see why a wireway would be worse. But I don't really know for sure.
 
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