What is the resistance of 500 feet of uncoated copper with a cross-sectional area of 250,000 circular mils?

Prepare for the Fundamental Code Calculations Test with engaging quizzes and exercises. Explore various question formats and receive instant feedback. Achieve excellence in code calculations with our comprehensive study materials and expert-designed exercises!

To determine the resistance of the copper conductor, the formula used is:

[ R = \frac{ρ \cdot L}{A} ]

where:

( R ) is the resistance,
( ρ ) is the resistivity of copper (approximately ( 10.4 , \text{Ω mil} \cdot \text{ft} ) at room temperature),
( L ) is the length in feet,
( A ) is the cross-sectional area in circular mils.

Given:

Substituting the values into the formula:

First, we can express the resistance for the specific measurements:

[ R = \frac{10.4 , \text{Ω mil} \cdot \text{ft} \times 500 , \text{ft}}{250,000 , \text{circular mils}} ]

Carrying out the multiplication in the numerator gives:

[ R = \frac{5200 , \text{Ω mils}}{250,000}