Quote Originally Posted by prattz99 View Post
Okay great, so I've been using 310.15(B)(16) correctly then?

A breaker rated at 75C I can then use #3THHN copper rated at 90C I've within the NEC to fuse it for 100 amps. Good to go?
With 75° C terminations at both end #3 THHN has an ampacity of 100 amps so you're code complaint. Even if you used a 75° C conductor like THWN it would still be rated for 100 amps.