Juniper QFX3500, Hardware Documentation

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CAUTION: Before you connect power to the device, 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 device (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 device chassis to connect to the
earth ground. For instructions on connecting earth ground, see “Connecting Earth
Ground to a QFX3500 Device” on page 334 or “Connecting Earth Ground to QFX3600
or QFX3600-I Devices” on page 308 .
•
Install the power supply in the chassis. For instructions on installing a power supply in a QFX3500 device,
see “Installing a Power Supply in a QFX3500 Device” on page 453 . For instructions on installing a power
supply in a QFX3600 or QFX3600-I device, see “Installing a Power Supply in a QFX3600 or QFX3600-I
Device” on page 447
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 a QFX3500, QFX3600 or QFX3600-I device:
1. Attach the grounding strap to your bare wrist and to a site ESD point.
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.
•
The cable with very high resistance (indicating an open circuit) to chassis ground is negative (–) and
will be installed on the V– (input) DC power input terminal.
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