In lockout/tagout practices, what distinguishes a lock from a tag?

• A. A lock physically prevents energization while a tag only communicates that the equipment is locked out
• B. A tag physically prevents energization; a lock only communicates the status
• C. A lock is optional; a tag is required
• D. A lock and tag have the same effect

Answer: (A)

In lockout/tagout, the key distinction is that a lock on the energy‑isolating device provides a physical barrier that prevents the equipment from being energized. Only the person who placed the lock (or someone with the key) can remove it, ensuring the device stays de-energized during work. A tag is a warning notice attached to the device that communicates that it is locked out and who is responsible, but it does not mechanically stop energy flow; energization could occur if the tag is ignored or bypassed. Therefore, the lock is the protective control, while the tag serves as a communication tool used to supplement the lock or when a lock cannot be applied.