what sort of system?
you're generally looking at 2 sorts of things, a) power to fixture, b) control to fixture. a may contain b.
i.e. you're runnign a building off of dmx controlled dimmers.
each fixture will have some sort of power going to it, either dimmed, contactor, or constant. (not including transformers or ballasts)
each fixture may also have lv dmx going to it to tell it to change color or dim.
so, for each fixture you need: power source, and control source, however if the fixture has a control unit, you may have power to each fixture and control shared across them. the control panels will generally have the same thing. (although they may be power over ethernet)
so, each critter has a "power" circuit that will tie to some sort of power, or to it's driver/transformer and a "control" circuit that will tie to it's control signal, or nothing if the transformer receives that.
now, with that in mind, structure how you circuit each fixture. i.e. dimmed circuits get D###, contactor circuits get C### and constant power circutis get B### (breaker or branch) control circuits are a different location in the tag, and are ### (or hex) where no additional control (just a dimmed incandescent on line voltage) is necessary you leave it blank.
