Differentiate between de‑energizing a circuit and locking it out.

• A. Locking it out means removing electrical power from the circuit.
• B. De‑energizing means removing electrical power from the circuit.
• C. De‑energizing means removing electrical power from the circuit; locking it out means placing a physical lock and tag to prevent re‑energization until the lock is removed by the authorized person.
• D. Lockout is the same as de‑energizing.

Answer: (C)

De-energizing is the act of removing electrical power from a circuit so no energy is available. But turning off power alone doesn’t guarantee it won’t be restored by someone else. Locking it out adds a controlled barrier: a physical lock on the energy-isolating device plus a tag that communicates that the equipment is under maintenance and who is responsible. This lockout prevents re-energization until the authorized person removes the lock, ensuring that only they can restore power. In sequence, you de-energize to eliminate power, then apply the lock and tag to maintain that safe state while work is done, and only the person who placed the lock can remove it. Therefore, the best description is that de-energizing means removing electrical power from the circuit; locking it out means placing a physical lock and tag to prevent re-energization until the lock is removed by the authorized person.