What is the maximum circuit length in feet for a 208-volt load drawing 14 amps using 12 AWG copper conductors while limiting the voltage drop to 3%?

To determine the maximum circuit length for a 208-volt load drawing 14 amps using 12 AWG copper conductors while limiting the voltage drop to 3%, it's essential to understand the relationship between voltage, current, and the characteristics of the conductors.

First, calculate the allowable voltage drop based on a 3% maximum drop from 208 volts:

[

0.03 \times 208 \text{ volts} = 6.24 \text{ volts}

]

Next, apply the voltage drop formula, which accounts for the resistance of the conductor and the distance of the circuit:

[

V_d = I \times R \times 2L

]

Here, (V_d) is the voltage drop, (I) is the current (14 amps), (R) is the resistance per 1,000 feet of 12 AWG copper wire (approximately 1.93 ohms), and (L) is the one-way length of the circuit in feet.

Rewrite the equation to find the distance:

[

L = \frac{V_d}{I \times R \times 2}

]

Substituting the values we have: