T640 Dc Power Electrical Safety Guidelines - Juniper T640 Hardware Manual

T640 DC Power Electrical Safety Guidelines

Copyright © 2013, Juniper Networks, Inc.
The following electrical safety guidelines apply to a DC-powered router:
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 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
INPUT 1 for a three-input 240-A DC power supply in
per input for a four-input 240-A DC power supply, or 56 A @ –48 VDC per input for a
six-input DC power supply.
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.
WARNING: For the six-input DC power supply, failure to provide the required
circuit breaker or current-limiting fuse for each DC power cable can cause
injury or damage to equipment.
For the six-input DC power supply, each –48 VDC facility DC source input power cable
must be equipped with a current-limiting fuse or circuit breaker external to the Juniper
Networks equipment rated at 80 A (–48 VDC) maximum. The voltage rating of the
facility DC source circuit breaker must be 80 V minimum. We recommend an 80 A
circuit breaker or current-limiting fuse rated for each 60 A DC power cable.
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.
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.
Appendix A: T640 Safety and Regulatory Compliance Information
2–INPUT
and
INPUT 0
mode, 48 A @ –48 VDC
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