I'm installing a sub-panel for a new addition. My load calc suggests a 50amp load for the sub-panel. So, I'm planning a 50amp feeder breaker in the main panel with #6 feeder wire to the sub-panel. But, the local retail stores don't carry (Siemens) panels smaller than 100amp. I checked with the local inspector (Seattle) and he said that it's common practice to feed a larger sub-panel (e.g., 100amp) from a smaller main feeder breaker/wire (e.g. 50amp, #6 wire).
The problem is that the 100amp main breaker in the sub-panel I bought lists a wire gauge range of "4 - 3/0". I assume this means I cannot connect #6 wire to it? I don't want to size up the feeder wire/breaker, so what are my options? Are there 100amp sub-panels that will accept smaller wire? BTW, the inspector mentioned that I might run into this issue, but I didn't really follow his recommended solution. Best I could tell, he was suggesting shimming the wire somehow at the 100amp breaker/connecter. That doesn't seem right to me... Is there some sort of adapter available for this situation?