Juniper QFX5220, Руководство по оборудованию, Страница: 140 / 247

CAUTION: Before you connect power to the switch, a licensed electrician must attach
a cable lug to the ground and power cables that you supply (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.
•
Install the power supply in the chassis. For instructions on Installing a power supply in a QFX5220, see
“How to Install an AC Power Supply in a QFX5220” on page 160 .
WARNING: A DC-powered QFX5220 is intended for installation only in a restricted
access location.
Ensure that you have the following parts and tools available:
•
A spare JPSU-1600W-1UDCAFI or JPSU-1600W-1UDCAFO for QFX5220-32CD (not provided)
•
Phillips (+) screwdriver, number 2 (not provided)
•
Multimeter (not provided)
WARNING:
Connecting DC Power to a QFX5220-32CD-D
To connect DC power to the DC model QFX5220-32CD:
1. Attach the grounding strap to your bare wrist and to a site ESD point on the switch.
2. Verify that the DC power cables are correctly labeled before making connections to 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.
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