If a balanced 3-phase line is properly functioning, what is the amperage on the neutral?

In a properly functioning balanced 3-phase system, the phases are designed to carry equal loads. In such a scenario, the currents in each of the three phases are equal in magnitude and evenly spaced in time. Since the loads are balanced, the sum of the currents flowing through each of the three phases effectively cancels each other out when measured at the neutral point.

The neutral conductor serves to balance the phases, but in ideal circumstances where the load is completely balanced, the currents in the three phase wires will sum to zero. Therefore, the amperage on the neutral would be zero, indicating that there is no net current flowing through it. This condition confirms the effectiveness of the balanced load in a 3-phase system, making the neutral conductor unnecessary for carrying any current.

In contrast, unbalanced loads would create a situation where the current in the neutral conductor could be non-zero, as the differing phase currents would not cancel out completely. However, that is not the case in a properly functioning system as described in the question.