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Catalyst 4948E and Catalyst 4948E-F Switch Installation Guide
OL-21561-02
Chapter 3 Installing the Switch
Connecting Power to the Switch
To connect source DC power to the DC-input power supply installed in the Catalyst 4948E switch,
follow these steps:
Step 1 Verify that all of the site power and grounding requirements described in “Power Requirements” section
on page 2-11 have been met and the chassis is properly grounded.
Step 2 Verify that power is off to the DC circuit you are going to attach to the DC-input power supply. As an
added precaution, place the appropriate safety flag and lockout devices at the source power circuit
breaker, or place a piece of adhesive tape over the circuit breaker handle to prevent accidental power
restoration while you are working on the circuit.
Step 3 Connect the DC cables to the source DC circuit breaker.
Step 4 Verify that the DC-input power supply is fully seated in the chassis power supply bay and that the captive
installation screw on the power supply is tight.
Step 5 Remove the snap-on plastic safety cover from the DC-input power supply terminal block.
Step 6 Attach the appropriate size and type of lugs to the source DC cables.
Either insulated crimp-on spade lugs or insulated crimp-on ring connectors can be used on the source
DC cables. They should be sized according to local and national installation requirements and electrical
codes.
Note The wire should be sized according to local and national installation requirements and electrical
codes. Use only copper wire.
Step 7 Connect the source DC cable lugs to the power supply terminal block posts in this order (see Figure 3-6):
• Ground cable lug to the power supply ground terminal post.
• Negative (–) source DC cable lug to the power supply negative (–) terminal post.
• Positive (+) source DC cable lug to the power supply positive (+) terminal post.
Step 8 After ensuring that all of the cable connections are secure, reinstall the terminal block cover.
Caution To prevent a short circuit or shock hazard after wiring the DC-input power supply, you must reinstall the
terminal block cover.
Caution In a system with dual DC-input power supplies, connect each power supply to a separate power source.
In case of a power source failure to one supply, the second power source should still be available.