Figure 54: Typical Source DC Power Cabling Scheme for a Single DC Power Module—Version 3 Power System
A separate ground connection is not required for the version 2 or version 3 power systems. For more information
see the
NEBS Supplemental Unit Bonding and Grounding Guidelines, on page 44
.
Note
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, be sure that power source cables are connected
to the power modules using 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
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.
• Green (or green and yellow) cable typically indicates that it is a ground cable.
DC power modules contain reverse voltage protection circuitry to prevent damage to the power module if it
detects a reverse polarity condition. No damage should occur from reverse polarity, but you should correct a
reverse polarity condition immediately.
Caution
For a list of the nominal and acceptable value ranges for source DC power, see
Technical Specifications
chapter from
Cisco ASR 9000 Series Aggregation Services Router Overview and Reference Guide
Cisco ASR 9000 Series Aggregation Services Router Hardware Installation Guide
43
Preparing for Installation
DC-Powered Router