Safety and Isolation on a High-Voltage Hybrid Service
A hybrid vehicle is booked for replacement of a 12 V auxiliary battery and a check of the charging system. The workshop manual states the high-voltage system must be isolated before any work near the orange cables. The vehicle has a service plug under the rear seat and a high-voltage battery rated at 245 V. A new apprentice is assisting and has not completed high-voltage training. The vehicle is in a shared bay with other jobs running, and the workshop has insulated gloves but no lockout tag or dedicated high-voltage bay.
1. Decide whether the job can proceed and describe the isolation steps you would follow before any work begins.
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The job should not proceed until the isolation requirements are met. The 12 V battery replacement itself may not require high-voltage isolation, but the charging-system check may bring the technician near high-voltage components, and the manual requires isolation for work near the orange cables.
The apprentice must not perform or assist with high-voltage work without training. I would assign them to non-high-voltage tasks outside the isolation zone.
Isolation steps: park the vehicle clear of other work, remove the key and keep it away from the vehicle, wait the manufacturer's specified discharge time after isolating, remove the service plug and store it under the technician's control, verify zero voltage at the high-voltage terminals with a meter rated for the system voltage, and confirm the meter on a known live source before and after the test. Gloves must be inspected and tested. Without a lockout tag or a controlled area, I would not begin.
2. The workshop cannot supply a lockout tag or a dedicated bay today. Recommend how to manage the risk and what you would tell the service manager.
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The risk is that another person reconnects the high-voltage system or moves the vehicle while work is in progress. Without a lockout tag, that risk cannot be adequately controlled.
I would recommend rescheduling the high-voltage portion of the job until the tag and a controlled area are available, and completing only the 12 V battery replacement if the manual permits it without isolation. If the vehicle must stay, I would place it in a marked exclusion zone, remove the service plug and keep it in my control, and inform every person in the bay.
I would tell the service manager plainly: the job cannot be done safely to the manual's requirements with the equipment on hand, the apprentice is not trained, and proceeding would breach the isolation procedure. I would ask for the tag, a barrier, and a scheduled bay, and record the decision on the job sheet.