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MX2008 DC Power Electrical Safety Guidelines and
Warnings
IN THIS SECTION
MX2008 DC Power Electrical Safety Guidelines | 575
DC Power Electrical Safety Warnings for Juniper Networks Devices | 576
MX2008 DC Power Electrical Safety Guidelines
The following electrical safety guidelines apply to a DC-powered router:
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 60 A per feed @ –48 VDC (nominal) for the system. We
recommend that the 48 VDC facility DC source be equipped with a circuit breaker rated at
80 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% 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 80 A.
A DC-powered router that is equipped with a DC terminal block is intended for installation in a restricted
access location only. 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.
575
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