Dell PowerEdge C1100 Getting Started With page 11

Connecting the Power Cable(s)
Connect the system's power cable(s) to the system and, if a monitor is used,
connect the monitor's power cable to the monitor. Plug the other end of the
power cables into a grounded electrical outlet or a separate power source such
as an uninterrupted power supply (UPS) or a power distribution unit (PDU).
Securing the Power Cable(s)
Release the latch on the retainer unit and pull the clamping ring towards
the end of the strip. Open the clamping ring and insert the power cable.
Close and push back the clamping ring until it is as close as possible to
the system. Check to ensure that the power cable is secured to the system.
9
Getting Started With Your System