What size copper conductor would be required for a 240V, 1Ø circuit supplying a noncontinuous load of 27.5A at a distance of 145', and a maximum voltage drop of 3%?

• A. No. 10
• B. No. 12
• C. No. 8
• D. No. 6

Answer: (A)

To determine the proper size of a copper conductor for a 240V, single-phase circuit supplying a noncontinuous load of 27.5A at a distance of 145 feet, while aiming for a maximum voltage drop of 3%, it's important to perform calculations based on the given parameters.

The first step is to calculate the total permissible voltage drop in volts. Given that the voltage drop should not exceed 3%, the total allowable drop can be calculated as follows:

1. Calculate the maximum voltage drop:

[

\text{Max voltage drop} = 240V \times 0.03 = 7.2V

]

Next, to find the required ampacity, we need to take into account the length of the circuit. The length of the conductor run should be considered twice (for the round trip), hence:

2. Total length of the circuit:

[

\text{Total distance} = 145' \times 2 = 290'

]

Using the formula for voltage drop for a single-phase circuit, we can express the voltage drop in terms of resistance and the current:

[

\text{Voltage Drop (VD)} = \frac{