In a balanced three-phase, four-wire system, what happens to the current in the neutral conductor?

In a balanced three-phase, four-wire system, the current in the neutral conductor should ideally not flow. This is due to the fact that in a balanced system, the sum of the currents flowing in the three phases is equal to zero at any given instant. This means that the three phase currents are of equal magnitude and 120 degrees apart in phase, which results in their vector sum being zero.

When all three phases carry equal current, the neutral wire serves primarily as a safety element and does not carry current under normal operating conditions in a balanced load scenario. This is a fundamental principle in three-phase power systems and is crucial for maintaining efficiency and safety.

In situations where loads are unbalanced or when there are harmonic currents present, the neutral may carry current. However, in a balanced system, the design intends for the neutral to be free of current flow, confirming the assertion that the current does not flow in the neutral conductor.