How is the high-voltage system secured from switching on again?

How is the high-voltage system secured from switching on again?

• A. By removing the battery entirely
• B. Through an approved Lockout/Tagout (LOTO) process
• C. With a mechanical interlock only
• D. By restarting the vehicle then turning off

Answer: (B)

Lockout/Tagout (LOTO) is the method used to keep the high-voltage system from turning back on. It provides a formal process to de-energize, isolate, and control all energy sources so the system cannot be re-energized while work is being done. This means applying locking devices to energy controls to physically prevent re-energization and attaching warning tags that indicate the system is not to be operated. Before work begins, the technician verifies there is no voltage and that any stored energy is discharged, then the locks stay in place until the job is finished and all safety checks are complete. This approach is reliable and auditable, covering all potential energy paths and ensuring that only the person who placed the lock can remove it and re-energize the system. Other options don’t provide the same level of control. Removing the battery entirely isn’t practical or sufficient because other energy sources can still energize the system, and it doesn’t prevent re-energization if someone bypasses the removal. A mechanical interlock alone may stop some operations but can be bypassed or fail, and it doesn’t address all energy sources or provide a clear warning. Restarting the vehicle and turning off again does not guarantee the system stays de-energized and can create new hazards during the transition.

Lockout/Tagout (LOTO) is the method used to keep the high-voltage system from turning back on. It provides a formal process to de-energize, isolate, and control all energy sources so the system cannot be re-energized while work is being done. This means applying locking devices to energy controls to physically prevent re-energization and attaching warning tags that indicate the system is not to be operated. Before work begins, the technician verifies there is no voltage and that any stored energy is discharged, then the locks stay in place until the job is finished and all safety checks are complete. This approach is reliable and auditable, covering all potential energy paths and ensuring that only the person who placed the lock can remove it and re-energize the system.

Other options don’t provide the same level of control. Removing the battery entirely isn’t practical or sufficient because other energy sources can still energize the system, and it doesn’t prevent re-energization if someone bypasses the removal. A mechanical interlock alone may stop some operations but can be bypassed or fail, and it doesn’t address all energy sources or provide a clear warning. Restarting the vehicle and turning off again does not guarantee the system stays de-energized and can create new hazards during the transition.