what are the potential problems of unbalanced loading of three phase circuits

 

How much unbalancing... and to the same machine, house, neigbourhood... ?

 

what are the potential problems of unbalanced loading of three phase circuits

Do you mean under normal loading or fault conditions? You might need to be a bit more specific in your question.

For instance - In a typical 3-phase + neutral supply at the connection point, the installer will try to balance the loads evenly across the phases. The more complex the installation the more difficult this might become - particularly if loads with sizable power factor issues are present in the mix. The neutral conductor is usually sized to allow for a significant imbalance across the phases.