How to read the NEC code book?

Read the NEC by structure, never front to back. Chapters 1 through 4 hold the general rules that govern everything; 5 through 7 modify them for special occupancies and equipment; chapter 8 is communications; chapter 9 is the tables.

The numbering is an address system: 210.52 means chapter 2, article 210, section 52. Learn ten landmark articles and you know your way around: 210 branch circuits, 220 load calcs, 240 overcurrent, 250 grounding, 310 conductors, 430 motors.

Start every lookup at the index, not by flipping.

Exam students drill tab-and-find speed; field users mostly need the same dozen tables, which is why cited results beat memorization.

That is the philosophy behind the NEC 220 load calculator: every answer arrives with its article attached, so the book opens to the right page.