Red Seal Electrician Practice
Safety and work practicesQuestion 608 of 1506

A machine has one electrical disconnect and one mechanical energy shutoff. How should a worker lock it out?

  1. One lock, on the electrical disconnect only
  2. One lock, on the door of the control panel
  3. Two locks, one on the disconnect and one on the shutoff
  4. No lock, if a tag is hung on the control panel
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Correct answer: Two locks, one on the disconnect and one on the shutoff

Every energy source that affects the task gets a personal lock, so both the disconnect and the shutoff are locked.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 3.5: Safe Practices

Practice safety and work practices

Questions last reviewed: 18 October 2026