What is the minimum size of SO cord for a motor supplied from a 120/240-volt, 3-ph, 4-wire panel based on its nameplate information?

To determine the minimum size of SO cord for a motor supplied from a 120/240-volt, 3-phase, 4-wire panel, it is essential to consider the current rating specified on the motor's nameplate. The National Electrical Code (NEC) provides guidelines on wire sizes based on the current that the motor draws, ambient temperature, and installation conditions.

Typically, for motor applications, the ampacity of the conductors must be established and must adhere to NEC Table 310.15(B)(16) based on the insulation type, installation method, and other relevant conditions. For SO cords, which are designed for flexible applications and can handle moisture and physical wear, the sizing should also take into account the continuous load component.

If the ampacity for the motor's specific current rating corresponds to a size 9 gauge wire according to NEC standards, it would be deemed the minimum acceptable size to ensure proper operation and safety. Choosing a wire that is too small can lead to overheating, voltage drop, and potential insulation failure.

Thus, when the nameplate information indicates that the motor's load requires a minimum of 9 gauge wire, this would confirm that it is indeed the correct size for safe and efficient operation of the motor supplied from