You need to turn off power to all system devices when you do the following:
Replace or add hardware.
Move the system from one location to another.
Prepare for an expected power outage or natural disaster such as an approaching electrical storm.
Turn the power off for system devices, including the CPU, the monitor, and external devices such as disks, tapes, and printers.
Before you turn off power to all system devices, you should shut down the system cleanly, as described in the preceding sections.
Select one of the following methods to shut down the system:
Turn off the power to all devices after the system is shutdown. If necessary, also unplug the power cables.
After power can be restored, use the following steps to turn on the system and devices.