Article 240 ?

[JDB3]

I'm thinking that it is article 240 that another guy & I are having discussions (on-line) about. What is the exact article that allows wire to have a larger breaker on it than the rating in 315 , in regards for air conditioning units. Specifically one that has a name plate rating of 30 amp over current rating? Thanks

 

[Rick 0920]

Table 240.4 (G) lists the Articles in which the conductor ampacities do not apply to T. 310.16. In instances such as motor start up where the inrush current could trip a circuit breaker, a larger OCPD may be used but you have to refer to the specific Articles for conditions of such use. Motors for instance, have overload protection that will trip the heaters long before it ever reaches that amperage that the OCPD would allow.

 

[don_resqcapt19]

It is the conductor sizing and protection rules in Article 440. The table in 240 just refers you to the parts of Article 440 that apply. Those parts being Part III and Part IV.