Connecting Power To A Dc-Powered Chassis - Cisco NCS 4000 Series Hardware Installation

Connecting Power to a DC-Powered Chassis

Connecting Power to a DC-Powered Chassis
This section contains the procedures to connect the DC source power cables to a DC-powered chassis.
The color coding of source DC power cable leads depends on the color coding of the site DC power source.
Because there is no color code standard for source DC wiring, you must be sure that power source cables are
connected to the power module with the proper positive (+) and negative (–) polarity:
• In some cases, the source DC cable leads might have a positive (+) or a negative (–) label. This is a
• Green (or green and yellow) cable typically indicates that it is a ground cable.
DC power modules contain circuitry to trip the breaker on the power module if the power module detects
Caution
a reverse polarity condition. No damage should occur from reverse polarity, but you should correct a
reverse-polarity condition immediately.
To ensure that power remains off while you are performing this procedure, lock-out/tag-out the DC circuit
Warning
breaker switch in the OFF (0) position until you are ready to turn it on.
Follow these steps to connect the DC source power cables to a DC power tray:
Procedure
Step 1
Verify that the power switch is set to the OFF (0) position. The power switch is on the right of the power tray.
Step 2 Remove the clear plastic safety covers that fit over the DC power connection terminal studs.
Step 3 Verify the following resistance values on both power shelves:
• The resistance between the positive and negative power terminal studs of each input must be greater
• The resistance between each positive terminal stud and bare metal surface on the power shelf must be
• The resistance between each negative terminal stud and bare metal surface on the power shelf must be
Note
Step 4
Connect the DC power cables in the following order:
a) Positive cable first.
b) Negative cable last.
Step 5 Repeat Step 4 for the other power modules installed in the tray.
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relatively safe indication of the polarity, but you must verify the polarity by measuring the voltage
between the DC cable leads . Be sure that the positive (+) and negative (–) cable leads match the positive
(+) and negative (–) labels on the power module when making the measurement.
than 90 KOhm.
greater that 10 MOhms.
greater that 10 MOhms.
Typical hand held Ohm meters will not measure 10 MOhms; instead they will auto range to acquire
a measurement and give an out-of-range reading. This is an acceptable reading provided that the
meter is in calibration.
Installing Power Components