Contradiction between 230.90 & 310.12 ??

[Brendon Smith]

I know the 83% rule in 310.12 allows the service conductor to be smaller than the main disconnect, but how does this not contradict with 230.90? 230.90 says the over current protective device can’t be greater than the ampacity of the service phase conductor.. Can anyone help me understand how this isn’t a contradiction?

 

[wwhitney]

What year NEC are you looking at? The 2017 has various exceptions to 230.90, including:

Exception No. 5: Overload protection for 120/240-volt, 3-wire, single phase dwelling services shall be permitted in accordance with the requirements of 310.15(B)(7).

Cheers, Wayne

 

[roger]

Read exception #5 to 230.90

Roger

 

[Brendon Smith]

Thank you! I can’t believe I missed that exception!.. Thanks for your replies!