The minimum circuit conductor size in a 120/208-volt 3-phase panel for a given motor is ___ AWG.

In determining the minimum circuit conductor size for a motor connected to a 120/208-volt 3-phase panel, it's essential to reference the National Electrical Code (NEC) guidelines, particularly Article 430, which covers motors. For three-phase motors, the conductors must be adequately sized to handle the rated current of the motor without excessive heating and to ensure safe operation.

The choice of 10 AWG for the minimum circuit conductor size is based on the typical wire sizing requirements for three-phase circuits. For a 15-20 amp motor (which would be common at 120/208 volts in a residential or light commercial setting), the conductor must be sized considering both the full load current and any applicable factors such as insulation type and installation conditions.

In this context, 10 AWG wire is recognized as suitable for carrying the necessary current while preventing voltage drop and ensuring safety. Sizing too small could lead to overheating and potential failure, while sizing too large might be unnecessary and could lead to increased costs and installation challenges.

This adherence to proper sizing helps maintain electrical efficiency, safety, and compliance with code requirements, reinforcing the importance of following proper electrical standards in motor installation.