Why is a lockout device considered more reliable than a tagout device for energy isolation?

• A. Tagouts are not required by OSHA.
• B. A lock physically prevents re-energization.
• C. Tags degrade quickly.
• D. Tags are only for documentation.

Answer: (B)

The main idea is that energy isolation needs a method that prevents all re-energizing during maintenance. A locking device provides a positive mechanical barrier that physically blocks the energy source, so the equipment cannot be re-energized until the lock is removed by the person who applied it. This creates a reliable, verifiable isolation. A tag, on the other hand, is only a warning notice and does not stop energy from being restored; it relies on people to follow the warning, and tags can be ignored, damaged, or removed. Because of that, lockout offers a more dependable way to protect workers during servicing.