The color coding of the source DC power cable leads to the DC-input power
Note
supply depends on the color coding of the site DC power source. Typically, green or
green/yellow is used for ground. Since there is no color code standard for the source DC
wiring, care must be taken to ensure that the proper polarity is connected to the DC-input
power supplies. In some cases the input cables might have a (+) and a (–) label. This is a
relatively safe indication of the polarity. However, you must verify the polarity by making
a voltage measurement before you turn the power supply on. When making the
measurement, the positive (+) lead and the negative (–) lead must always match the (+)
and (–) labels on the power supply.
When installing the unit, the ground connection must always be made first and
Warning
disconnected last.
Step 7
Remove the outer nut and locking washer from each power supply terminal and attach the
source DC power cable lugs to the power supply terminals in the following order: ground
to ground, positive to positive (+), and negative to negative (–).
If your site is equipped with an external power supply circuit breaker alarm, thread the
Step 8
power supply circuit breaker external alarm leads up through the power supply handle and
attach them to the circuit breaker alarm terminal block on the power supply faceplate
according to the notes you made in a previous step. (Some sites might not be equipped
with a power supply circuit breaker external alarm.)
Position the source DC power cable leads underneath the power supply handle on the
Step 9
power supply faceplate in the following order from left to right: negative (–), positive (+),
and ground. Place the DC power cable bracket over the power cable leads and secure the
cable leads and the cable bracket to the power supply faceplate with the two screws that
you removed earlier.
Step 10
Verify that the source DC wiring from the source DC breaker to the power supply is
correct and that the terminal connections on the power supply are correct and tight.
You must make the verification with a calibrated DC voltmeter. Always connect
Note
the positive (+) and negative (–) leads to the corresponding positive (+) and negative (–)
leads on the power supply.
Place the power supply front cover so that the keyholes are positioned over the two
Step 11
standoff screws on the power supply faceplate. Slide the cover down slightly to engage
the two screws and secure it in place by tightening the two screws.
Cisco 12012 Gigabit Switch Router DC-Input Power Supply Replacement Instructions
Removing and Replacing a DC-Input Power Supply
15
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