We are installing numerous FFU (fan filter units) for a small clean room. The motors for these fans are 277v single phase.
Per 430.6(A)(1) "The values given in Table 430.147, Table 430.148, Table 430.149, and Table 430.150, including notes, shall be used to determine the ampacity of conductors or ampere ratings of switches, branch-circuit short-circuit and ground-fault protection, instead of the actual current rating marked on the motor nameplate."
Table 430.148 Full-Load Currents in Amperes, Single-Phase Alternating-Current Motors doesn't have a specific column for 277V.
Based on the HP of the fan motor, do we size the ampacity of conductor and branch-circuit short circuit based on the closest column (230V) of 430.148 or use the nameplate data or some other method?
Per 430.6(A)(1) "The values given in Table 430.147, Table 430.148, Table 430.149, and Table 430.150, including notes, shall be used to determine the ampacity of conductors or ampere ratings of switches, branch-circuit short-circuit and ground-fault protection, instead of the actual current rating marked on the motor nameplate."
Table 430.148 Full-Load Currents in Amperes, Single-Phase Alternating-Current Motors doesn't have a specific column for 277V.
Based on the HP of the fan motor, do we size the ampacity of conductor and branch-circuit short circuit based on the closest column (230V) of 430.148 or use the nameplate data or some other method?