What is lockout/tagout used for?

• A. To tag equipment that needs to be replaced.
• B. To ensure equipment is de-energized and cannot be started during maintenance or repair.
• C. To lock doors during service.
• D. To label circuit breakers by color.

Answer: (B)

Lockout/tagout is used to prevent unexpected energization and start-up of equipment while someone is working on it. It works by isolating the energy source and applying a lock to the energy‑isolating device, along with a tag that identifies who placed it and why. The lock physically prevents the machine from being restarted, while the tag communicates important safety information. This combination protects workers from shocks, burns, or other injuries that could happen if a machine were powered back on during maintenance.

The other options don’t address energy isolation. Tagging alone doesn’t prevent startup, and locking doors or labeling circuit breakers by color are about access or identification, not safely isolating electrical energy during service.