Dell PowerEdge R815 Guide De Mise En Route page 7

Securing the Power Cable(s)
Bend the system power cable into a loop as shown in the illustration and secure
the cable to the bracket using the provided strap. Plug the other end of the
power cable into a grounded electrical outlet or a separate power source such
as an uninterrupted power supply (UPS) or a power distribution unit (PDU).
Turning On the System
Press the power button on the system and the monitor. The power indicators
should light.
5
Getting Started With Your System