What is the required conductor ampacity for a 10-horsepower, 230-volt, single-phase motor?

To determine the required conductor ampacity for a 10-horsepower, 230-volt, single-phase motor, you can start by calculating the full-load current using the formula specific to single-phase motors. The formula for calculating the full-load current (in amperes) is:

[ \text{Full Load Current (I)} = \frac{\text{Horsepower} \times 746}{\text{Voltage} \times \text{Efficiency} \times \text{Power Factor}} ]

For a more simplified calculation without accounting for efficiency and power factor, you can use a standard value for single-phase motors. Generally, for a 10-horsepower motor, the full-load current is approximately 50 amps. However, you must consider provisions for starting current and continuous use, which may involve using larger conductors.

When including safety and possibly derating for longer conductor runs or increased ambient temperatures, the calculated ampacity can be adjusted upward. Based on the National Electrical Code (NEC) guidelines for derating and continuous load considerations, the final ampacity may end up being around 62.5 amps, which reflects a prudent safety margin.

This is why the required conductor ampacity for a 10-horsepower