Power Connection Guidelines For Dc-Powered Systems - Cisco CAtalyst 4500 Series Installation Manual

Chapter 2 Preparing for Installation
Power Connection Guidelines for DC-Powered
Systems
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This section provides the basic guidelines for connecting the Catalyst 4500 series
switch DC-input power supplies to the site power source or AC power shelf:
All power connection wiring should conform to local and national codes.
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DC (–) and DC return (+) terminals are evaluated for use with 1/0 AWG wire
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(1400W DC supply only).
The ground terminal is evaluated for use with 6 AWG wire (10 AWG for the
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multi-input power supply).
DC (–) and DC return (+) wire lugs shall not exceed 0.83 inches in width
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(0.378 inches for the multi-input power supply).
For DC power cables, we recommend that you use commensurately rated,
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high-strand-count copper wire cable. Connection to the DC-input power
supply requires one earth ground cable, one source DC (–), and one source
DC return (+). The length of the cables depends on your switch location.
These cables are not available from Cisco Systems. They are available from
any commercial cable vendor.
The color coding of the source DC power cable leads depends on the color
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coding of the site DC power source. Typically, green or green and yellow
indicate that the cable is a ground cable. Because there is no color code
standard for source DC wiring, you must ensure that the power cables are
connected to the DC-input power supply terminal block in the proper (+) and
(–) polarity. In some cases, the source DC cable leads might have a positive
(+) or a negative (–) label. This label is a relatively safe indication of the
polarity, but you must verify the polarity by measuring the voltage between
the DC cable leads. When making the measurement, the positive (+) lead and
the negative (–) lead must always match the (+) and (–) labels on the DC-input
power supply terminal block.

Power Connection Guidelines for DC-Powered Systems

Catalyst 4500 Series Switches Installation Guide
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