Do keep in mind that 230.79(C) is specifically addressing the service disconnecting means. It is not addressing any feeder disconnecting means, and it is not addressing the service conductors, the feeder conductors, or the OCPD. If the service disconnecting means happens to be a circuit breaker, then it and the OCPD are one and the same. But they need not be. I can envision a "tiny house" that has a calculated load of 80 amps. I can use a 100 amp fused disconnect as the service disconnecting means, and thereby satisfy the minimum requirement of 230.79(C). But then I can fuse it at 80 amps. The OCPD would be the fuses, and they don't have to satisfy the 100 amp minimum of 230.79(C).
Charles E. Beck, P.E., Seattle
Comments based on 2014 NEC unless otherwise noted.