IBM System x3650 M3 4255 Installation And User Manual page 129

CAUTION:
The power control button on the device and the power switch on the power
supply do not turn off the electrical current supplied to the device. The device
also might have more than one power cord. To remove all electrical current
from the device, ensure that all power cords are disconnected from the power
source.
Statement 8:
CAUTION:
Never remove the cover on a power supply or any part that has the following
label attached.
Hazardous voltage, current, and energy levels are present inside any
component that has this label attached. There are no serviceable parts inside
these components. If you suspect a problem with one of these parts, contact
a service technician.
To install an ac power supply, complete the following steps:
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Chapter 2. Installing optional devices