FEEDER SIZE

[czars]

For residences, I've always heard that a feeder conductor never has to be larger than the service conductors. Can anyone point me to the NEC paragraph that states that???

 

[augie47]

I think you are looking for wording in 310.15(B)(7)

Note that it says the ampacity of the feeder so its a bit more involve than conductor size.
If you change from one type conductor to another or you encounter different ambient, etc you must take that into account.