In which position must a disconnecting means be capable of being locked?

The disconnecting means must be capable of being locked in the closed position to ensure that it can be safely operated under load during maintenance or repair. This requirement is essential for safety because locking the disconnect in the closed position prevents accidental operation by unauthorized personnel, maintaining a robust safeguard against unintended energization of the circuit. This is critical for ensuring that workers can confidently perform their tasks without the risk of electrical shock or equipment damage.

In contrast, while locking in other positions might seem relevant, the specific requirement focuses on locking the disconnect when it is closed. This emphasizes the importance of maintaining clear boundaries when equipment is energized, thereby enhancing overall safety protocols in electrical installations. Locking mechanisms are designed to facilitate compliance with safety standards, ensuring that all personnel remain safe while working with or near energized equipment.