Red Seal Electrician Practice
Motor controlsQuestion 98 of 1506

In a ladder diagram, what do the two vertical lines represent?

  1. The rungs, which hold the loads and control devices
  2. Two phases of the motor, which feed the contactor
  3. The wire numbers that are written along each conductor
  4. The rails, which are the two sides of the control power supply
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Correct answer: The rails, which are the two sides of the control power supply

The horizontal lines are the rungs. Each is a separate parallel branch.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 6.1: “Ladder” Diagrams

Practice motor controls

Questions last reviewed: 18 October 2026