We previously began looking at the more detailed requirements for circuits not over 600A [210.19(A)]. An important observation is those requirements are preceded by four Informational Notes, and the location of these Notes is important. These Notes don’t refer to you information that’s nice to know; they refer you to information you must apply.
If a branch circuit serves more than one receptacle for cord-connected portable loads, the ampacity of its conductors must be at least that of the branch circuit [Sec. 210.19(A)(2)]. Remember that the branch circuit overcurrent protective device (OCPD) defines the branch circuit. So if you have a 20A breaker supplying that circuit, the conductors in question here must have an ampacity of at least 20A.
The same rule applies to branch circuits supplying household cooking appliances. But in addition, the conductor ampacity can’t be less than the load served. Also for these circuits, the maximum OCPD size for ranges of 8.75kW or larger is 40A. Commercial ranges aren’t household ranges, so they are exempted from the 40A limit. A couple of other exceptions apply, too.
For other types of loads not specified in in Sec. 210.19(A)(3) or Sec. 210.2, the conductor must be at least 14AWG and of sufficient ampacity for the loads served [Sec. 210.19(A)(4)] (there are two exceptions).
