T4000 Dc Power Electrical Safety Guidelines - Juniper T4000 Hardware Manual

T4000 Router Hardware Guide
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T4000 DC Power Electrical Safety Guidelines

The following electrical safety guidelines apply to a DC-powered router:
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: Failure to provide the required circuit breaker or current-limiting
fuse for each DC power cable can cause injury or damage to equipment.
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 100 A (–48 VDC) maximum for the six-input DC power supply, or as required
by local code. 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 a 100 A circuit breaker or current-limiting
fuse rated for each 80 A DC power cable
The marked input voltage of –48 VDC for a DC-powered router 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.
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.
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 @ –48 VDC
per input for the six-input DC power supply.
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 60 A DC power cables or 100 A for 80 A DC power
cables. .
NOTE: Only 60 A feeds are currently supported.
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.
Copyright © 2013, Juniper Networks, Inc.