What minimum size THW copper branch circuit conductors are required to supply a 230 volt, 5 hp motor?

To determine the minimum size THW copper branch circuit conductors for a 230-volt, 5 horsepower motor, you've referred to the National Electrical Code (NEC) that provides guidelines on conductor sizing based on the full load current of motors.

For a standard 5 hp motor operating at 230 volts, the full load current can be approximately calculated using the formula:

Full Load Current (A) = (Horsepower x 746) / Voltage

For a 5 hp motor, the calculation would be:

Full Load Current = (5 x 746) / 230 ≈ 16.24 A

According to NEC guidelines, after determining the full load current, you would then reference the appropriate tables to identify the minimum conductor size required to handle the load safely.

Based on NEC Table 310.16 for THW copper conductors at an ambient temperature rating of 30°C (86°F), a conductor rated for 20 A is suitable for this application, which effectively corresponds to a minimum conductor size of 10 AWG. This size ensures that the conductors can handle the load without overheating and maintain the safety of the electrical system.

In this case, selecting 10 AWG as the minimum size THW copper branch