Which practice is used to prevent re-energizing the high-voltage system during maintenance?

• A. Removing the battery is sufficient
• B. Power down with the vehicle but not lockout
• C. Through an approved Lockout/Tagout (LOTO) process
• D. Disconnecting the 12V system only

Answer: (C)

Isolating and securing energy sources with an approved Lockout/Tagout process prevents re-energizing the high-voltage system during maintenance. Lockout/Tagout involves identifying all sources of energy, de-energizing them, and applying a physical lock and a warning tag to the energy-isolating devices so no one can restore power until the lock is removed by the person who applied it. It also includes verification steps to confirm there is no residual energy and, if needed, discharging stored energy. Removing the battery alone may not stop all energy paths or prevent reattachment and re-energization. Simply powering down without lockout leaves the system vulnerable to re-energization. Disconnecting only the 12V system does not address the high-voltage energy sources involved. The formal LOTO process is the reliable way to ensure the HV system stays de-energized during maintenance.