Dc Power Electrical Safety Guidelines And Warnings; T640 Dc Power Electrical Safety Guidelines - Juniper T640 Hardware Manual

DC Power Electrical Safety Guidelines and Warnings

T640 DC Power Electrical Safety Guidelines

Copyright © 2010, Juniper Networks, Inc.
T640 DC Power Electrical Safety Guidelines on page 329
DC Power Electrical Safety Warnings for M Series, MX Series, and T Series
Routers on page 330
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 at least 68 A
@ –48 VDC for a two-input 160-A DC power supply, 67 A @ –48 VDC per
for a three-input 240-A power supply in
INPUT 1
per input for a four-input 240-A power supply.
We recommend that the 48 VDC facility DC source be equipped with a circuit breaker
rated at 80 A (–48 VDC) for a two-input 160-A DC power supply,
80 A (–48 VDC)minimum for a three-input 240-A power supply, or 60 A (–48 VDC)
minimum for a four-input 240-A power supply, 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 for a two-input 160-A DC power supply or three-input
240-A DC power supply or 60 A for a four-input 240-A DC power supply.
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.
Appendix A: T640 Safety and Regulatory Compliance Information
2–INPUT
INPUT 0 and
mode, or 48 A @ –48 VDC
329