Red Seal Electrician Practice
Power factor and three-phaseQuestion 1060 of 1506

What can a high triplen harmonic current do in a four-wire Y system with many nonlinear loads?

  1. Reduce the line voltage to zero
  2. Cancel the line currents
  3. Overheat the neutral conductor
  4. Reverse the phase sequence
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Correct answer: Overheat the neutral conductor

The neutral then carries far more than the phase conductors would suggest from the fundamental alone.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.7: Harmonics in Polyphase Power Systems

Practice power factor and three-phase

Questions last reviewed: 18 October 2026