Lenovo ThinkSystem DS Series Hardware Installation And Maintenance Manual page 19

• The electrical distribution system must provide a reliable earth connection for each enclosure in the rack.
• Each PCM or PSU in each enclosure has an earth leakage current of 1.0mA. The design of the electrical
distribution system must take into consideration the total earth leakage current from all power supply modules
in all enclosures. The rack will require labeling with "High Leakage Current. Earth connection essential before
connecting supply."
• The rack—when configured with the enclosures—must meet the safety requirements of UL 60950-1 and IEC
60950-1.
Rack system safety precautions 19