The minimum size circuit conductors for a 208-230/115-V 1Ø 7½ hp motor are how many AWG?

The correct answer is a size 6 AWG conductor for a 208-230/115-V 1Ø 7½ hp motor, primarily due to the requirements set forth in the National Electrical Code (NEC). When determining the minimum conductor size for motors, factors such as the motor’s horsepower rating, voltage, starting currents, and ambient temperature are taken into account.

For a 7½ horsepower motor operating at a voltage range of 208-230 volts, the NEC provides a formula to calculate the appropriate conductor size. Generally, an ampacity table is referenced, which classifies copper conductors and their carrying capacities based on specific conditions.

In this case, the NEC indicates that a size 6 AWG conductor has sufficient ampacity to handle the continuous load and potential inrush current demand when the motor starts. This size of conductor helps to ensure that the motor can start without overheating the wire, maintaining safe operation without voltage drop under load conditions.

Thus, selecting a 6 AWG conductor aligns with the NEC guidelines, ensuring safety and efficiency for the motor's operation.