I am a little bit uncomfortable with this requirement that signs be listed.
Not that listing is a bad thing; it's just that listing - of either the entire sign, or it's components - is only a small part of the entire installation.
I've seen some pretty elaborate local 'sign ordinances' that go into great detail as to the placemant, anchoring, bracing, etc. of signs. When you consider the surprising weight of many signs, the effect of wind & weather upon them, and the chance they have of being mounted over the exact place where folks are likely to be standing or walking, you can see the need for this. None of these issues, though, are going to be addressed in the listing.
Then, lest we forget .... there are plenty of signs for which listing is not appropriate. For example, a simple painted sheet of wood, with a spotlight shining on it.
At the other extreme, we have several signs here so large that they have their own service installed, with multiple panels and nearly countless circuits. In such a sign, the listing addresses only a fraction of the code issues.
Let's not forget the 'big picture.'
