[kamocat]

Yeah, I noticed that exception. I don't suppose FIRST would approve a schematic.

Joe, by that logic FIRST would not permit replacing blown fuse. Auto-resetting breakers provide a different degree of protection than fuses, and so it makes sense to restrict that replacement, for a limited application where it is necessary. I see nowhere that it is their intent to prevent a smaller fuse being used. (They allow 12 gauge wire to be used with a 20A breaker, though you are only REQUIRED to use 18 gauge or larger.)