How to determine the Total power by the Line values

Phase values are often not or difficult to access. In addition, the line values are particularly important for the electrical protection in the control box. Is there an equation for determining the total three-phase power with line values, which applies to both star and delta connection? There is one:

3 Phase Current - how to determine the power from the line values

3 Phase Current - how to determine the power from the line values


Does the Line voltage change when switching from star to delta? And if so, how?
How must the line current change when switching from star to delta?