Red Seal Electrician Practice
Safety and work practicesQuestion 1203 of 1506

Why might a position sensor with a sliding wiper be unsafe in a dusty area with combustible dust?

  1. The wiper would draw too much current.
  2. The wiper can arc and ignite the dust.
  3. The dust would raise the resistance.
  4. The wiper would freeze.
Show answer

Correct answer: The wiper can arc and ignite the dust.

Arcing at the wiper contact can start an explosion in a combustible atmosphere. An LVDT has no sliding contact.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 12.6: AC Instrumentation Transducers

Practice safety and work practices

Questions last reviewed: 18 October 2026