Juniper EX4650 Series, Hardware Manual, Page: 88 / 195

CAUTION: Replace a failed power supply with a blank panel or new power supply
within one minute of removal to prevent chassis overheating.
Connecting DC Power to an EX4650 Switch
The EX4650 is shipped from the factory with two 650 W power supplies. Each power supply is a
hot-removable and hot-insertable field-replaceable unit (FRU) when the second power supply is installed
and running. You can install replacement power supplies in the two slots next to the fan modules without
powering off the switch or disrupting the switching function.
WARNING: A DC-powered EX4650 is intended for installation only in a restricted access
location.
NOTE: The battery returns of the DC power supply must be connected as an isolated DC return
(DC-I).
Before you begin connecting DC power to the switch:
•
Ensure that you have taken the necessary precautions to prevent electrostatic discharge (ESD) damage
(see “Prevention of Electrostatic Discharge Damage” on page 177 ).
•
Ensure that you have connected the switch chassis to earth ground.
CAUTION: Before you connect power to the switch, a licensed electrician must attach
a cable lug to the grounding and power cables that you supply. A cable with an
incorrectly attached lug can damage the switch (for example, by causing a short circuit).
To meet safety and electromagnetic interference (EMI) requirements and to ensure
proper operation, you must connect the chassis to earth ground before you connect
it to power. For installations that require a separate grounding conductor to the chassis,
use the protective earthing terminal on the switch chassis to connect to the earth
ground. For instructions on connecting earth ground, see Connecting Earth Ground to
an EX4650.
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