Red Seal Electrician Practice
Wiring and componentsQuestion 585 of 1506

In power system wiring, why can the resistance of the conductors not be ignored, even though it is very small?

  1. The current is high, so a small resistance causes a large drop.
  2. The current is low, so the resistance is the only limit to flow.
  3. Power conductors are made of a material with negative resistance.
  4. Voltage drop only occurs in any wire shorter than about one metre.
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Correct answer: The current is high, so a small resistance causes a large drop.

Voltage drop is current times resistance, so a high current makes a small resistance matter.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 2.7: Circuit Wiring

Practice wiring and components

Questions last reviewed: 18 October 2026