Red Seal Electrician Practice
Power factor and three-phaseQuestion 1162 of 1506

Why is a low power factor a problem for the supply wiring?

  1. The wiring carries less current and so runs cold.
  2. The voltage rises above the nominal value at the load.
  3. The wiring must carry more current for the same power.
  4. The frequency of the supply drops under the extra load.
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Correct answer: The wiring must carry more current for the same power.

Reactive current does no work, yet it still heats the conductors and uses up capacity.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 11.3: Calculating Power Factor

Practice power factor and three-phase

Questions last reviewed: 18 October 2026