Juniper EX4600 Series Hardware Manual page 168

EX4600 Switch Hardware Guide
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WARNING: DC-powered EX4600 switches are intended for installation only
in a restricted access location.
NOTE: The battery returns of the DC power supply should 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
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
Switch" on page
Install the power supply in the chassis. For instructions on installing a power supply in
an EX4600 switch, see "Installing a Power Supply in an EX4600 Switch" on page
Ensure that you have the following parts and tools available:
DC power source cables (14–16 AWG) with ring lug (Molex 190700069 or equivalent)
(not provided)
Phillips (+) screwdriver, number 2 (not provided)
Multimeter (not provided)
To connect DC power to an EX4600 switch:
Attach the grounding strap to your bare wrist and to a site ESD point.
1.
Verify that the DC power cables are correctly labeled before making connections to
2.
the power supply. In a typical power distribution scheme where the return is connected
to chassis ground at the battery plant, you can use a multimeter to verify the resistance
of the –48V and RTN DC cables to chassis ground:
The cable with very low resistance (indicating a closed circuit) to chassis ground is
positive (+) and will be installed on the V+ (return) DC power input terminal.
"Connecting Earth Ground to an EX4600
146.
Copyright © 2014, Juniper Networks, Inc.
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