– When working on a double-insulated or battery-operated system, use an ESD common ground or reference point. You can use coax or connector-outside shells on these systems. – Use the round ground prong of the ac plug on ac-operated computers. Grounding requirements Electrical grounding of the computer is required for operator safety and correct system function. Proper grounding of the electrical outlet can be verified by a certified electrician. Safety notices (multilingual translations) The safety notices in this section are provided in the following languages: • English • Arabic • Brazilian Portuguese • French • German • Hebrew • Japanese • Korean • Spanish • Traditional Chinese DANGER DANGER DANGER 4 T480 Hardware Maintenance Manual