circular mill verses square inch

[kimrichi]

i asked this question before and looks like i did not find the answer i am looking for
if our cables are round why do not we consider cir. mill instead of sq. in when calcualating like raceway size for instance

 

[ActionDave]

The shape of the raceway is a non-issue. There are only so many sq inches inside of it and it can be calculated.

 

[Smart $]

i asked this question before and looks like i did not find the answer i am looking for
if our cables are round why do not we consider cir. mill instead of sq. in when calcualating like raceway size for instance

Probably because conductor circular mils do not include the cross-sectional area of the insulation (or jacket, armor, voids, and filler material of cables).