Juniper Networks M5 - Manual (Page 157)

Safety Guidelines and Warnings
•
Green and yellow—Earth
•
Blue—Neutral
•
Brown—Live
•
When a router is equipped with two AC power supplies, both power cords (one for each
power supply) must be unplugged to completely disconnect power to the router.
DC Power Electrical Safety Guidelines
The following electrical safety guidelines apply to DC-powered routers:
•
DC-powered routers are 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
13.5 A @ 48 VDC. The 48 VDC facility DC source should be equipped with a circuit
breaker rated at 20 A minimum. Incorporate an easily accessible disconnect device
into the facility wiring. 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 20 A.
•
You must connect only to a DC power source for which the output complies with the
safety extra low-voltage (SELV) requirements of UL 1950, CSA C22.2 No. 950-95, EN
60950, and IEC 60950 to a DC-input terminal block.
•
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.
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.
•
The marked input voltage of –48 VDC for DC-powered routers 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.
Safety and Regulatory Compliance Information 137