Juniper ACX1000 Hardware Manual page 179

• A DC-powered router is equipped with a DC terminal block that is rated for the power requirements
of a maximally configured router. To supply sufficient power, terminate the DC input wiring on a
facility DC source capable of supplying at least 5 A @ –48 VDC per input for each power supply. We
recommend that the 48-VDC facility DC source should be equipped with a circuit breaker rated at 5
A @ –48 VDC) minimum, or as required by local code.
Incorporate an easily accessible disconnect device into the facility wiring. In the United States and
Canada, the 48 VDC facility should be equipped with a circuit breaker rated a minimum of 125
percent of the power provisioned for the input in accordance with the National Electrical Code in the
US and the Canadian Electrical Code in Canada.
• Run two wires from the circuit breaker box to a source of 48 VDC. Use appropriate gauge wire to
handle up to 5 A
• Be sure to connect the ground wire or conduit to a solid office (earth) ground. A closed loop ring is
recommended for terminating the ground conductor at the ground stud.
• A DC-powered router that is equipped with a DC terminal block is intended only for installation in a
restricted access location. In the United States, a restricted access area is one in accordance with
Articles 110-16, 110-17, and 110-18 of the National Electrical Code ANSI/NFPA 70.
NOTE: Primary overcurrent protection is provided by the building circuit breaker. This breaker
should protect against excess currents, short circuits, and earth faults in accordance with NEC
ANSI/NFPA70.
• Ensure that the polarity of the DC input wiring is correct. Under certain conditions, connections with
reversed polarity might trip the primary circuit breaker or damage the equipment.
• For personal safety, connect the green and yellow wire to safety (earth) ground at both the router
and the supply side of the DC wiring.
• The marked input voltage of –48 VDC for a DC-powered router is the nominal voltage associated
with the battery circuit, and any higher voltages are only to be associated with float voltages for the
charging function.
• Because the router is a positive ground system, you must connect the positive lead to the terminal
labeled +, the negative lead to the terminal labeled –, and the earth ground to the chassis grounding
points.
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