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Conductors supplying several motors, or a motor(s) and other load(s), shall have an ampacity not less than the sum of each of the following:
  1. 125 percent of the full-load current rating of the highest rated motor, as determined by 430.6(A)
  2. Sum of the full-load current ratings of all the other motors in the group, as determined by 430.6(A)
  3. 100 percent of the noncontinuous non-motor load
  4. 125 percent of the continuous non-motor load.
Informational Note: See Informative Annex D, Example No. D8.
Exception No. 1: Where one or more of the motors of the group are used for short-time, intermittent, periodic, or varying duty, the ampere rating of such motors to be used in the summation shall be determined in accordance with 430.22(E). For the highest rated motor, the greater of either the ampere rating from 430.22(E) or the largest continuous duty motor full-load current multiplied by 1.25 shall be used in the summation.
Exception No. 2: The ampacity of conductors supplying motor-operated fixed electric space-heating equipment shall comply with 424.4(B).
Exception No. 3: Where the circuitry is interlocked so as to prevent simultaneous operation of selected motors or other loads, the conductor ampacity shall be permitted to be based on the summation of the currents of the motors and other loads to be operated simultaneously that results in the highest total current.

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