As always great explanation with great illustrations. Thanks Ryan for sharing your knowledge and expertise. Your contribution to the trad is much appreciated.
As your photo clearly showed, I think the NEC should address conduit fill for large gauge wires and/or large diameter conduit with small gauge wires. For example, 54 #10-AWG THW wires in a 2” EMT, or 10 #2-AWG THW wires in a 2” EMT, are both crazy (hard to work with and to do maintenance or inspection) yet it’s code compliant.
Excellent discussion, and a very thorough analysis Ryan. However, as pertaining to the NM cable calculations at 36:17 I believe if you had two 12-2 cables you would be limited to 31% of the Cross -Sectional area not 40% of the conduit per Chapter 9 table 1.