Cisco XR 12404 - Manual (Page 147)

5-23
Cisco XR 12404 Router Installation Guide
OL-13830-02
Chapter 5 Maintaining the Router
Removing and Replacing a DC PDU
Step 3 Loosen the terminal block screws to disconnect the positive, negative, and ground
wires from the DC PDU terminal block of the faulty PEM (
Figure 5-14 ).
Warning To prevent injury and damage to the equipment, always remove the source DC
power leads and ground from the power shelf terminals in the following order:
(a) negative (–), (b) positive (+), (c) ground.
Caution Before removing wires, be sure to note the color for each type of wire (positive,
negative, and ground). Because there is no color code standard for source DC
wiring, you must be sure which power wires are connected to the proper positive
(+) and negative (–) terminal ports. Typically, green (or green and yellow) indicate
a ground wire, while power wire leads may be labeled positive (+) or negative (–).
Because this is not always the case, the safest way to indicate the polarity of a wire
is to note its color and identify it as described in this procedure.
Figure 5-14 DC PDU Terminal Block
1 Negative port 3 Ground port
2 Positive port 4 Terminal port connector screws
66949
+
GND
1
4
2
3
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