Is it sufficient to lock out the control circuit on an electrically operated breaker?

• A. Yes
• B. No, the breaker itself must be locked open
• C. Only if the control circuit is locked
• D. Not necessary

Answer: (B)

Locking out the control circuit alone does not guarantee safety when dealing with electrically operated breakers. Even if the control power is blocked, the main disconnect can still be closed by other means, or the control circuit could re-energize the breaker, causing reclosure. The only reliable way to ensure the circuit cannot energize is to lock the breaker itself in the open position, providing a physical barrier to current flow. In practice, you place a padlock on the breaker handle in the open position and attach a tag, confirming that the circuit is de-energized and cannot be reclosed unintentionally. This physical isolation is what truly protects personnel during maintenance, rather than relying solely on locking the control circuit.