Cisco Catalyst 9407R

DC-input wire for positive circuit (+ B)5Lug secured with two nuts1
DC-input wire for positive circuit (+A)6Heat-shrink sleeve on all the wires2
DC-input wire for negative circuit (- A)7Grounding wire3
--DC-input wire for negative circuit (-B)4
Step 7 Close the terminal block cover and finger-tighten the captive installation screw (approximately 0.25 Nm).
Cisco Catalyst 9400 Series Switches Hardware Installation Guide
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Removing and Replacing FRUs
Connecting the DC-Input Wires