What is the minimum size copper wire required for a 230-volt, single-phase circuit supplying a 65-ampere load over a distance of 250 feet?

To determine the minimum size of copper wire required for a 230-volt, single-phase circuit carrying a 65-ampere load over a distance of 250 feet, several factors need to be considered, including the ampacity of the wire and the voltage drop.

For a 65-ampere load, the wire must be able to handle this current without overheating, which is directly linked to the wire's ampacity. The National Electrical Code (NEC) provides guidelines for the ampacity of various wire sizes depending on the application.

In addition to ampacity, voltage drop is a critical consideration, especially over a distance such as 250 feet. A common recommendation is to keep the voltage drop to no more than 3% for feeders. The longer the wire run, the larger the wire must be to minimize voltage drop.

When we look at standard wire sizes, a 2 AWG copper wire typically has an acceptable ampacity for a load of 65 amperes while also providing a voltage drop within acceptable limits over a distance of 250 feet. Generally, 1 AWG may be too large unless considering specific circumstances (like very high ambient temperature or bundling), while 3 AWG or 4 AWG would likely