HOLT Electricians Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Question: 1 / 400

What size feeder conductor is required for two motors: one rated at 7 ½ horsepower, 230 volts, and another rated at 5 horsepower, 230 volts?

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To determine the correct size feeder conductor for the two motors, you first need to calculate the total amperage that the motors will draw.

For a motor, the full load current can be calculated using the formula:

\[ \text{Full Load Current (Amps)} = \frac{\text{Horsepower} \times 746}{\text{Voltage} \times \sqrt{3}} \]

Since the motors are likely single-phase, the formula simplifies to:

\[ \text{Full Load Current} = \frac{\text{Horsepower} \times 746}{\text{Voltage}} \]

Now, calculate the current for the 7.5 HP motor:

\[ \frac{7.5 \times 746}{230} \approx 24.3 \text{ Amps} \]

Next, calculate for the 5 HP motor:

\[ \frac{5 \times 746}{230} \approx 16.2 \text{ Amps} \]

Adding these together gives:

\[ 24.3 + 16.2 \approx 40.5 \text{ Amps} \]

In accordance with the National Electrical Code (NEC), when determining feeder conductor sizes, you

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