Dc Power Shelf Guidelines - Cisco CRS-1 System Description

DC Power System
The Cisco CRS 4-slot line card chassis DC power system provides 4,000 watts to power the chassis. (To
provide power redundancy, up to 8,000 watts are available.) Each DC-powered chassis contains four DC
power supplies for 2N redundancy. The power input module (PIM) provides the input power
connections. Note that each power connection has two cables: –48 VDC and return. The power input
module (PIM), DC power input shelf, and the power supplies are field replaceable.
The Cisco CRS 4-slot line card chassis requires a total of four dedicated pairs of 60-A DC input power
connections, one pair for each of the power supplies, to provide redundant DC power to the Cisco CRS
4-slot line card chassis midplane.
For full 2N redundancy, we recommend that you have two independent –48 VDC power sources to
provide power to the Cisco CRS 4-slot line card chassis. Connect the two 60-A DC inputs on the left to
one wiring block, and the two 60-A DC inputs on the right to the other wiring block.

DC Power Shelf Guidelines

At sites where the Cisco CRS 4-slot line card chassis is equipped with a DC power input shelf and power
supplies, observe the following guidelines:
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•
•
•
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Figure 2-5
End View
0.60
Cisco CRS Carrier Routing System 4-Slot Line Card Chassis System Description
2-8
All power connection wiring should follow the rules and regulations in the National Electrical Code
(NEC) and any local codes.
Each DC-input power entry module connection is rated at 60-A maximum. A dedicated,
commensurately rated DC power source is required for each power supply connection.
Each power supply requires one –48 VDC input, or four inputs for each power shelf (in which each
input consists of a pair of positive and negative wires), and one power-shelf grounding wire.
For DC power cables, we recommend that you use commensurately rated, high-strand-count copper
wire cable. Each DC power supply requires one 48 VDC input, which means that there are two wires
for each power supply, or eight total wires (four pairs) for each power shelf, plus the grounding wire.
The length of the wires depends on the router's location. These wires are not available from
Cisco Systems; they are available from any commercial vendor.
DC power cables must be terminated by cable lugs at the power-shelf end. The lugs should be dual
hole and able to fit over M6 terminal studs at 0.625-in (15.88-mm) centers (for example, Panduit
part number LCD2-14A-Q or equivalent) (see
DC Power Cable Lug
Ø 0.27
2 holes
0.25 0.63
0.10
Figure 2-5).
All measurements in inches
2.40
Crimp area
0.38
Chapter 2 Chassis Power System
OL-10805-10