Came across a sub panel today that is fed by a 60A breaker located in the main panel. Feeding this panel is a #6 SER conductor. Isn't this feeder undersized? From 310.15(B)(16), #6 AL is good for 50A at 75C (I am assuming terminations are 75C). Is this feeder allowed to be sized at 83%, or is that just for services? 2014 code applies here. Looks to me like #4 AL would bee the smallest size you could run for this application, so a #4 SER would be ok. Am I correct?