5Power SuppliesThe Z9000 supports two hot-swappable power supply units (PSUs) with integrated fans that providecooling for the system.The Z9000 supports AC and DC power supplies with two air-flow directions (normal and reversed). TwoPSUs are required for full redundancy, but the system can operate with a single PSU.NOTE: If you use a single PSU, install a blank plate in the other PSU slot. Dell Networkingrecommends using power supply 1 (PSU1) as the blank plate slot.The PSUs are field replaceable. When operating with full redundancy (two power supplies installed andrunning), you can remove and replace one PSU while the other PSU is running without disrupting traffic.WARNING: Electrostatic discharge (ESD) damage can occur if components are mishandled.Always wear an ESD-preventive wrist or heel ground strap when handling the Z9000 and itscomponents.WARNING: To prevent electrical shock, ensure that the Z9000 is grounded properly. If you do notground your equipment correctly, excessive emissions may result. To ensure that the powercables meet your local electrical requirements, use a qualified electrician.ComponentsThe following power supply options are available for the Z9000.• AC power supply with integrated fan• AC power supply with integrated reverse flow fan• DC power supply with integrated fan• DC power supply with integrated reverse flow fanThe PSUs in the Z9000 are field replaceable. When both power supplies are installed and running, youcan remove one power supply without interrupting traffic.Power Supply 0 (PSU0) is on the top of the Z9000; power supply 1(PSU1) is on the bottom of the Z9000system.WARNING: Prevent exposure and contact with hazardous voltages. Do not attempt to operatethis system with the safety cover removed.CAUTION: Remove the power cable from the PSU prior to removing the PSU. Also, do notconnect the power cable before you insert the PSU in the chassis.CAUTION: Be sure that the DC power source is turned off before attaching the cables to the DCconnectors on the Z9000.Power Supplies 23