Breakers, fuses, transformers, contactors, relays, conductors, and busbars — not what they are, but how an engineer actually selects and coordinates them, and where they fail in the field.
Most component overviews stop at "what it is." This module goes straight to selection criteria: interrupting ratings, trip curves, percent impedance, AC-3 contactor duty, ampacity derating, and short-circuit bracing — the ratings that actually decide whether a component survives the conditions it's specified into.
By the end of this module you should be able to explain why none of these seven component families gets selected in isolation — a breaker's required interrupting rating, a busbar's withstand rating, and a contactor's duty class are all set by the same system-level fault-current and inrush numbers, which Module 7's power-distribution content calculates in full.