What is the formula to determine voltage drop using circular mils?

The formula to determine voltage drop using circular mils is derived from the principles of electrical resistance and the properties of conductors. The correct formula, which is represented by the option you selected, incorporates several critical factors that contribute to voltage drop.

In the formula, the voltage drop (VD) is calculated by taking into account the length of the conductor (L), a constant that relates to the material's resistivity (K), and the current (I) flowing through the conductor. The circular mil area of the conductor (CM) is also a vital component since it directly influences the resistance of the conductor.

Using the factor of 2 in this calculation accounts for the round-trip length of current in the circuit, which is crucial in alternating current (AC) systems or any situations where current travels to a load and back to the source. This effectively addresses the total distance the current travels, ensuring accurate voltage drop calculations.

Understanding this formula is essential for designing electrical systems, as it allows engineers to ensure that voltage levels remain within permissible limits so that equipment functions correctly without significant power loss due to voltage drop over the length of the wire.