In a balanced three-phase system, what is the neutral current?

In a balanced three-phase system, the neutral current is zero. This is due to the nature of balanced loads, where the three phases carry equal currents that are 120 degrees out of phase with each other. When these currents are summed vectorially, they cancel each other out, resulting in no net current flowing through the neutral conductor.

This concept relies on the principle of symmetry in a three-phase circuit. Each phase contributes equally and oppositely to the neutral current, effectively balancing the electrical activity. In practical applications, this characteristic of balanced three-phase systems allows for the efficient use of the neutral wire, often reducing the overall wiring requirements in electrical installations.

In contrast, the other options imply scenarios that are not representative of a balanced system. High current suggests that there is an imbalance, which is not the case in this situation. Variable current would also indicate imbalances or fluctuations in load, and saying the neutral current is dependent on loads implies that as long as there's balance, the neutral current should distinctly remain zero regardless of specific loads. Thus, the correct answer emphasizes the importance of balance in three-phase systems, confirming that with balanced loads, the neutral current is indeed zero.