Attention: This unit may have more than one power supply cord. To completely remove
power, you must disconnect all power supply cords.
3. Switch off power to all external devices attached to the system unit, and then unplug the
device power cords from the electrical outlets.
Note: Because many external devices can be connected to the system unit, it may be
impractical for you to switch off power to all the devices and unplug their power
4. Open the rear door of the system unit.
5. Set the Master CB1 circuit breaker to Off.
6. If the battery backup unit is installed, set the Master CB2 circuit breaker to Off.
7. Unless you are servicing the system while signal cables or power cords are connected to
external devices, unplug the system unit power cord from the electrical outlet.
Immediately Stopping the AC Rack Containing a PDU
Attention: Unpredictable results can occur that affect your data files if you use this method
to stop the CPU enclosure or disk drive drawers.
If you need to switch off all power to the system quickly, set the Master CB1 and CB2 circuit
breakers to off. All power is switched off to the drawers connected to the PDU in this rack.
Other drawers in this rack may be provided power from a PDU in an attached rack.
Battery Backup Unit
Power Distribution Unit