Just to clarify a minor point. The PSX-AC is a special case where it has both terminals but generally does adhere to the above 3 rules. The common through a PSX-AC is not broken, the "hot" is the one that breaks or opens, and thus it follows rule #3. Again, the black common lines straight through clear to the terminal blocks are not broken in the even of a current trip event.
Another great diagram originally by @CAPPilot and further edited by me.
