Quote Originally Posted by jadnashua View Post
One way to think about this is the wall switch, rated at 15A that is controlling a 100W light bulb...works fine, lasts a long time, perfectly safe.
Fine, but would you feed this single 15 amp breaker with a 100 amp main, with the "real" 20 amp breaker perhaps 500' away in a basement?

I see some homeowner in the future deciding the 100 amp main is shot because his outlet is dead, and changing that before he finds the real infeed device. Simply an illogical and perhaps unsafe situation for what he might think he can add to that panel.