To ensure a device remains de-energized during repairs and maintenance, you should:

Choosing to lock out and tag out the device is the best practice to ensure it remains de-energized during repairs and maintenance. The lockout/tagout (LOTO) procedure is crucial in maintaining safety by physically preventing the operation of equipment while it is being serviced.

Locking out the device means applying a lock to the energy-isolating device, which physically prevents the equipment from being energized. Tagging out serves as a visual indicator that the device is not to be operated until repairs are completed. This combination of locking and tagging not only protects the technician performing the work but also communicates to others that the equipment is not in service, thereby reducing the risk of accidental energization.

Using just a tag without a lock, or merely notifying others, does not provide the physical barrier and assurance against unintended startup, which is why those approaches are not considered sufficient for ensuring safety during maintenance work.