Uneven voltage, also known as unbalanced voltage, occurs when there is a disparity in the electrical load between the two hot bus bars in your breaker box. This might sound minor, but it can wreak havoc on your electrical system, especially when dealing with sensitive equipment like a solar inverter. The effect of voltage unbalance can also be detrimental to equipment such as. Image Source: PNNL Report on the 9500 Node Test System, a large model designed to test the ability of advanced apps, including 3-phase Unbalanced Power Flow, over a wide range of typical distribution operations and grid conditions.