eric,
I was remembering what I first learned over a dozen years ago about wire sizes on branch circuits. I guess I confuzzled that with an overseas spec I recently ran into where the wire's size is also limited to a maximum size for the available amperage. The reasoning is that you don't want an electrician to run across, say, an 8 gauge wire coming from a branch from an outlet on a 7 amp breaker (Euro 230V value) because the electrician would then expect that A LOT of current was available, when it was not.