Dc Power Circuit Breaker Requirements For The Srx5400 Firewall; Dc Power Source Cabling For The Srx5400 Firewall - Juniper SRX5400 Hardware Manual

screw) ground lugs] provided on the chassis. This separate protective earth terminal
must be permanently connected to earth.

DC Power Circuit Breaker Requirements for the SRX5400 Firewall

Each DC power supply has a single DC input (–48 VDC and return) that requires a dedicated facility
circuit breaker. We recommend that you use a customer site circuit breaker rated for 40 A (–48 VDC)
minimum for each DC power supply, or as required by local code. Doing so enables you to operate the
firewall in any configuration without upgrading the power infrastructure.
If you plan to operate a DC-powered firewall at less than the maximum configuration and do not
provision a 40 A (–48 VDC) circuit breaker, we recommend that you provision a circuit breaker for each
DC power supply rated for at least 125% of the continuous current that the system draws at –48 VDC,
or as required by local code.

DC Power Source Cabling for the SRX5400 Firewall

Figure 14 on page 35 shows a typical DC source cabling arrangement.
Figure 14: Typical DC Source Cabling to the firewall
The DC power supplies must be powered by dedicated power feeds.
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