Question

Calculate the voltage drop for a 3 phase, 3 wire 480V circuit with a 15HP induction motor in RMC located 150 ft from the panel using 6 uncoated copper wire?

a) 2.58%
b) 4.62%
c) 6.74%
d) 8.91%

Answer 1

To calculate the voltage drop for a 3-phase, 3-wire circuit, use Ohm's Law. The correct answer is option b) 4.62%.

Step-by-step explanation:

To calculate the voltage drop for a 3-phase, 3-wire circuit, we need to use Ohm's Law. The formula for calculating voltage drop is V = I * R, where V is the voltage drop, I is the current, and R is the resistance of the wire. In this case, the current flowing through the wire is 15A, and the resistance of the wire can be calculated using the resistivity of uncoated copper wire. Assuming the resistivity is 1.724 x 10^-8 Ωm, the resistance of the 150ft long wire can be calculated using the formula R = (resistivity * length) / cross-sectional area. The cross-sectional area of a 6 gauge wire is approximately 13.3 mm^2. Substituting the values, we can calculate the resistance of the wire. Finally, substitute the resistance and current values into Ohm's Law to calculate the voltage drop. The correct answer is option b) 4.62%.