Ordinarily not a problem, but when it is an issue serious consequences can result. Any voltage unbalance issues are immediately identified as part of a standard power quality audit.
Typically medium and large commercial and industrial customers are supplied by means of three phase electricity. In an ideal world the measured value of all three phase voltages would be the same. Due primarily to unbalanced loads on the utility’s electrical network the three phase voltages experience different levels of regulation and voltage drop which causes them to be unequal at the customers’ point of supply. Small variations are of little consequence; however there are certain types of load that require that the imbalance be less than about 2 percent. The most notable load in this category is the three phase induction motor, as such motors overheat quite dramatically if the three phase supply voltage has significant imbalance present. Depending on their design, three phase rectifiers can also mal-operate or fail if the supply voltage is significantly unbalanced.
The type of equipment affected is often found in medium to large production facilities so the negative consequences can be quite significant.