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

DC Power Circuit Breaker Requirements for the SRX5400 Services Gateway

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 services
gateway in any configuration without upgrading the power infrastructure.
If you plan to operate a DC-powered services gateway 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 Services Gateway

Figure 13 on page 55 shows a typical DC source cabling arrangement.
Figure 13: Typical DC Source Cabling to the Services Gateway
Central office
ground
DC power supply on SRX5400
The DC power supplies must be powered by dedicated power feeds.
CAUTION:
The power source cables might be labeled (+) and (–) to indicate their polarity. There
is no standard color coding for DC power cables. The color coding used by the external
DC power source at your site determines the color coding for the leads on the power
cables that attach to the terminal studs on each power supply.
Central office
secondary
DC power
distribution
Ground
window
Central office
ground
You must ensure that power connections maintain the proper polarity.
Rectifiers
Plant
Batteries controls
Power plant and batteries
in same building
AC
55