Installation guide

2-25
Cisco IGX 8400 Series Installation Guide, Release 9.3.3 and Later Releases
OL-1165-06
Chapter 2 Preparing to Install
IGX 8420 or IGX 8430 Enclosure Installation
Two types of redundancy exist in the AC-powered system. One redundancy is that of AC power inputs.
A redundant AC power source from a building circuit that is independent of the other AC circuit
provides backup if one AC circuit at the site fails. The other redundancy is that of the 400 W power
supply modules. Redundancy of the 400 W power supplies provides a backup if a power supply fails.
In supporting single and dual AC inputs, power supply arrangements differ, as follows:
• When a system uses two AC inputs, the number of supplies that receive power from AC input A
must be the same as the number of supplies that receive power from AC input B. See Figure 2-10.
• When a system uses one AC source, the number of supplies must be installed in a contiguous
arrangement, beginning with slot A, then slot B, and so on. Because only one AC input is present,
the input connection has no alphanumeric designation.
Figure 2-10 shows a dual-input system. Facing the back of a dual-input system, AC input A is on the
left. AC input B in on the right. In a dual-input system, the input A supplies power supply slots A and
B. Input B supplies power to slots C and D. A single AC input system does not have these distinctions:
the single input receives AC power for supplies A–C. See Table 2-4 for power supply requirements.
Table 2-4 shows the minimal 400W unit requirements for different IGX 8410 configurations. The factors
that determine the number of supplies are as follows:
• The number of AC inputs
• The number of cards (one supply can power four cards)
• Power supply redundancy for backup
In Table 2-4 the System column shows the number of AC inputs. The Number of Cards Column shows
the number of cards at the cutoff point for more supplies. The Supply Redundancy Column indicates
whether the configuration includes a redundant supply for backup. For columns A through D, an X
shows that the corresponding slot in the power supply housing must have a power supply to meet the
configuration requirements. The part number for a power supply is IGX8410-PS-AC.
Table 2-4 Locations of Primary and Additional Power Supplies in an IGX 8410 Node
System Number of Cards
N+1 Supply
Redundancy A B C D
1 AC Input 4 or less No X
4 or less Yes X X
more than 4 No X X
more than 4 Yes X X X
2 AC inputs 4 or less X X
more than 4 XXXX