What is the voltage drop for a 120V, single-phase, two-wire branch circuit, 100' long, using copper conductors of 6,530 circular mils with a noncontinuous load of 13A?

• A. 4.20V
• B. 5.14V
• C. 6.75V
• D. 3.50V

Answer: (B)

To calculate the voltage drop for a single-phase circuit, we use the formula:

[

\text{Voltage Drop (V)} = \frac{2 \times \text{Length (ft)} \times \text{Current (A)} \times \text{Resistivity (Ohm-cmil/ft)}}{\text{Circular Mils}}

]

In this scenario, the branch circuit is 100 feet long with a current of 13A and conductors measuring 6,530 circular mils. The resistivity of copper is approximately 10.4 Ohm-cmil/ft. Let's break down the calculation.

1. Determine the total length for single-phase: Since it's a two-wire system, you multiply the one-way length by 2. Thus, 100 ft becomes 200 ft.

2. Plug the values into the formula:

[

\text{Voltage Drop} = \frac{2 \times 100 , \text{ft} \times 13 , \text{A} \times 10.4 , \text{Ohm-cmil/ft}}{6530 , \text{cmil}}

]

3. **Calculate it