What minimum size copper wire is needed for a 230-volt branch circuit with a 65-ampere load at a distance of 250 feet?

To determine the minimum size copper wire required for a 230-volt branch circuit with a 65-ampere load at a distance of 250 feet, it is important to consider both the ampacity of the wire and the voltage drop that occurs along the wire due to its length.

In general, copper wiring is utilized due to its high conductivity and lower resistance compared to other materials. The ampacity (or current-carrying capacity) of copper wire depends on the wire gauge, and specific sizes are rated for maximum current loads. To ensure safety and efficiency, it's crucial to use a wire size that can handle the specified current (in this case, 65A).

For a 65-ampere load over a distance of 250 feet, the voltage drop needs to be considered. A typical acceptable voltage drop is 3% for branch circuits, meaning the voltage drop should not exceed approximately 6.9 volts for a 230-volt circuit. This drop can be calculated using the formula:

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\text{Voltage Drop} = \frac{2 \cdot \text{Length} \cdot \text{Current} \cdot \text{Resistance per 1000ft}}{1000}

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