Juniper SRX 5800, Hardware Manual

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Figure 15: Power Distribution from DC and High-Capacity AC Power Supplies in the SRX5800 Services
Gateway Chassis
Zone 0 Zone 1
PEM0 PEM1 PEM2 PEM3
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NOTE: The craft interface draws its power from the SCBs installed in the SCB slots 0, 1, and 2
at the center of the card cage. In the standard configuration, with SCBs in slots 0 and 1, the craft
interface is powered on even when one of the two zones loses power. But if the chassis only
has one SCB installed, the craft interface draws all of its power from that card, and consequently
is powered off if the zone in which that SCB is installed loses power.
You can install either two or four DC power supplies or high-capacity AC power supplies. Two power
supplies are required to power the two zones, while four power supplies provide full redundancy for both
zones. The power supplies in slots PEM0 and PEM2 form a redundant pair, as do the power supplies in
slots PEM1 and PEM3. When two power supplies are installed for a zone, they share the load. If a power
supply fails, its redundant power supply assumes the full load of that zone without interruption.
If you do install only two power supplies, they must be installed so that one is in an odd-numbered slot
and the other is in an even-numbered slot. For example, you can install one high-capacity AC power supply
in each of the slots PEM0 and PEM1.
SRX5800 Services Gateway Standard-Capacity AC Power Supply
Each standard-capacity AC power supply has a corresponding AC appliance inlet located in the chassis
directly above the power supply. Each inlet requires a dedicated AC power feed and a dedicated
15 A (250 VAC) circuit breaker. See Figure 16 on page 50 .
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