Dc Power Electrical Safety Guidelines - Juniper JA2500 Junos Space Hardware Manual

JA2500 Junos Space Appliance Hardware Guide

DC Power Electrical Safety Guidelines

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180
A DC-powered device is equipped with a DC terminal block that is rated for the power
requirements of a maximally configured device.
NOTE: To supply sufficient power, terminate the DC input wiring on a facility
DC source that is capable of supplying a maximum inrush current of 30 A
at power-up
Incorporate an easily accessible disconnect device into the facility wiring. 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.
Run two wires from the circuit breaker box to a source of –48 VDC. (The range
supported by the DC power supply is –45 VDC to –60 VDC.)
A DC-powered device 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 must protect against excess currents, short circuits,
and earth grounding faults in accordance with NEC ANSI/NFPA 70.
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 device and the supply side of the DC wiring.
The marked input voltage of –45 VDC for a DC-powered device 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 device is a positive ground system, you must connect the positive lead to
the terminal labeled RTN, the negative lead to the terminal labeled –45 VDC, and the
earth ground to the device grounding points.
DC Power Disconnection Warning on page 181
DC Power Grounding Requirements and Warning on page 182
DC Power Wiring Sequence Warning on page 183
DC Power Wiring Terminations Warning on page 185
General Electrical Safety Guidelines and Warnings on page 175
Copyright © 2018, Juniper Networks, Inc.