What is the purpose of verifying zero energy after applying lockout/tagout devices?

• A. To test the system while energized
• B. To complete paperwork only
• C. To train new staff
• D. To ensure all energy sources are isolated and cannot release energy

Answer: (D)

Verifying zero energy after locking out and tagging a machine is about making sure every energy source has been isolated and cannot release energy during maintenance. After you apply LOTO devices, you want to confirm there is no electrical, mechanical, hydraulic, pneumatic, thermal, chemical, or gravitational energy that could cause the equipment to start, move, or release energy unexpectedly. This step typically involves trying to operate the controls in a controlled way to see that the system won’t energize, and using appropriate testing methods or instruments to verify de-energized circuits and that all energy sources are effectively blocked or relieved. By proving there is zero energy, workers are protected from injuries due to unexpected energization or energy release.