Dc Power Electrical Safety Guidelines And Warnings; Dc Power Electrical Safety Guidelines - Juniper SRX240 Hardware Manual

SRX240 Services Gateway Hardware Guide

DC Power Electrical Safety Guidelines and Warnings

DC Power Electrical Safety Guidelines

132
SRX240 Services Gateway Maintenance and Operational Safety Guidelines and
Warnings on page 125
This topic includes the following sections:
DC Power Electrical Safety Guidelines on page 132
DC Power Disconnection Warning on page 133
DC Power Grounding Requirements and Warning on page 134
DC Power Wiring Sequence Warning on page 135
DC Power Wiring Terminations Warning on page 136
The following electrical safety guidelines apply to a DC-powered services gateway:
A DC-powered services gateway is equipped with a DC terminal block that is rated for
the power requirements of a maximally configured services gateway. To supply
sufficient power, terminate the DC input wiring on a facility DC source capable of
supplying at least 5 A @ –48 VDC for the system. We recommend that the 48 VDC
facility DC source be equipped with a circuit breaker rated at 10 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 must be
equipped with a circuit breaker rated a minimum of 125% of the power provisioned for
the input in accordance with the National Electrical Code in the US and the Canadian
Electrical Code in Canada. 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. Use appropriate
gauge wire to handle up to 10 A.
A DC-powered services gateway 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 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 services gateway and the supply side of the DC wiring.
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