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Cisco ASR 903 Router Hardware Installation Guide
OL-25178-05
Chapter3 Installing the Cisco ASR 903 Router
Installing the Power Supply

Guidelines for AC-Powered Systems

Basic guidelines for AC-powered systems include the following:
Each chassis power supply should have its own dedicated branch circuit.
The circuit breaker should be sized according to the power supply input rating and local or national
code requirements.
The AC power receptacles used to plug in the chassis must be the grounding type. The grounding
conductors that connect to the receptacles should connect to protective earth ground at the service
equipment.
Installing the DC Power Supply
The following sections describe how to install a DC power supply in the CiscoASR 903 Router:
Installing the DC Power Supply Module, page3-21
Installing Terminal Block on the DC PEM Unit (A900-PWR550-D), page3-22
Installing Terminal Block Connector on the DC PEM Unit (A900-PWR550-D-E), page3-25
Activating the DC Power Supply, page3-26
Note This equipment is suitable for installation in Network Telecommunications Facilities and locations
where the NEC applies.
Note This equipment is suitable for installations utilizing the Common Bonding Network (CBN).
Note The grounding architecture of this product is DC-Isolated (DC-I) for DC-powered products.
DC-powered products have a nominal operating DC voltage of 48 VDC.

Installing the DC Power Supply Module

Perform the following procedure to install the power supply module:
Step1 Ensure that the system (earth) ground connection has been made. For ground connection installation
instructions, see the “Installing the Chassis Ground Connection” section on page3-7.
Step2 If necessary, remove the blank power supply filler plate from the chassis power supply bay opening by
loosening the captive installation screws.
Step3 Verify that power to the DC circuit connected to the power supply you are installing is off. To ensure that
power has been removed from the DC circuits, locate the circuit breakers for the DC circuits, switch the
circuit breakers to the OFF position, and tape the circuit-breaker switches in the OFF position.
Step4 Grasp the power supply handle with one hand. Place your other hand underneath the power supply, as
shown in Figure3-18. Slide the power supply into the power supply bay. Make sure that the power
supply is fully seated in the bay.