Red Seal Electrician Practice
Motor controlsQuestion 99 of 1506

On a control wire marked with number 25 that connects several devices, what is the rule for wire numbers?

  1. Every device terminal gets its own number, even if joined by a wire
  2. Every electrically continuous point has the same wire number
  3. The number changes whenever the wire size changes along the run
  4. The number changes at each junction or node in the circuit
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Correct answer: Every electrically continuous point has the same wire number

The number stays the same even if the wire colour, size or length changes.

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

Practice motor controls

Questions last reviewed: 18 October 2026