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Connecting the QFX5110 to Power

Connect the QFX5110 to Earth Ground

You must install the QFX5110 in a restricted-access location and ensure that the chassis is always properly grounded. The QFX5110 has a two-hole protective grounding terminal provided on the chassis. See Figure 1. Under all circumstances, use this grounding connection to ground the chassis. For AC-powered systems, you must also use the grounding wire in the AC power cord along with the two-hole grounding lug connection. This tested system meets or exceeds all applicable EMC regulatory requirements with the two-hole protective grounding terminal.

CAUTION:

If an external ground connection is required, ensure that a licensed electrician has attached an appropriate grounding lug to the grounding cable that you supply. Using a grounding cable with an incorrectly attached lug can damage the switch (for example, by causing a short circuit).

Note:

Mount your switch in the rack or cabinet before attaching the grounding lug to the switch. See Unpacking and Mounting the QFX5110.

Ensure that you have the following parts and tools available:

  • Grounding cable for your QFX5110 device—The grounding cable must be 14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code (not provided).

  • Grounding lug for your grounding cable—The grounding lug required is a Panduit LCD10-10A-L or equivalent (not provided).

  • Two 10-32 x 0.25 screws with #10 split-lock washers—Two screws and washers are used to secure the grounding lug to the side of the chassis (not provided).

  • Number 2 screwdriver.

An AC-powered QFX5110 switch chassis gains additional grounding when you plug the power supply in the switch into a grounded AC power outlet by using an AC power cord appropriate for your geographical location. See QFX5110 AC Power Cord Specifications.

To connect earth ground to a QFX5110:

  1. Connect one end of the grounding cable to a proper earth ground, such as the rack in which the switch is mounted.
  2. Place the grounding lug that is attached to the grounding cable over the protective earthing terminal.
  3. Secure the grounding lug to the protective earthing terminal with two screws and washers. See Figure 1
    Figure 1: Connecting a Grounding Cable to a QFX5110Connecting a Grounding Cable to a QFX5110
  4. Dress the grounding cable and ensure that it does not touch or block access to other device components and that it does not drape where people could trip over it.

Alternate Method to Ground QFX5110-48S-DC and QFX5110-32Q-DC Systems

Ensure that you have the following parts and tools available to ground the chassis using this method:

  • M5 pan-head screw x .08 mm with integrated washer (not provided)

  • M5 lug (not provided)

  • 12 AWG (2.5 mm²) standard wire, 90° C wire or heavier (not provided)

  • Number 2 screwdriver (not provided)

To connect earth ground to a QFX5110:DC power supply:

  1. Have a licensed electrician attached the M5 grounding lug to the grounding cable that you supply.

    CAUTION:

    Using a grounding cable with an incorrectly attached lug can damage the switch.

  2. Ensure that all grounding surfaces are clean and brought to a bright finish before grounding connections are made.

  3. Connect one end of the grounding cable to a proper earth ground, such as the rack in which the switch is mounted.

  4. Place the grounding lug that is attached to the grounding cable over the protective earthing terminal on the DC power supply.

  5. Use a screwdriver to secure the grounding lug to the protective earthing terminal with a M5 pan-head screw with integrated washer.

  6. Dress the grounding cable and ensure that it does not touch or block access to other device components and that it does not drape where people could trip over it.

We recommend that you connect earth ground to a QFX5110 DC chassis using the Connect the QFX5110 to Earth Ground method. However if you can’t access the chassis using the two-holed grounding lug, you can ground the chassis using the DC protective earthing terminal on the DC power supply.

The DC power supplies have a protective earthing terminal on the face that holds an M5 pan-head screw with integrated washer. See Figure 2.

Figure 2: DC Power Supply Faceplate on a QFX5110DC Power Supply Faceplate on a QFX5110
  1
—

Shunt negative input terminals (-48V)

  5
—

Protective earthing terminal

  2
—

Shunt positive input terminals (+RTN)

  6
—

Fault LED

  3
—

Terminal block

  7
—

Output LED

  4
—

Security latch

  8
—

Input LED

Connecting AC Power to a QFX5110

Ensure that you have a power cord appropriate for your geographical location available to connect AC power to the switch.

Before you begin connecting AC power to the switch:

  • Ensure that you have taken the necessary precautions to prevent electrostatic discharge (ESD) damage (see Prevention of Electrostatic Discharge Damage).

  • 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 Connect the QFX5110 to Earth Ground.

    On AC systems, the switch gains additional grounding when you plug the power supply in the switch into a grounded AC power outlet by using the AC power cord appropriate for your geographical location (see QFX5110 AC Power Supply Description).

    CAUTION:

  • Install the power supply in the chassis. For instructions on installing a power supply in a QFX5110, see Installing a Power Supply in a QFX5110.

The QFX5110 is shipped with two 650 W power supplies pre-installed. 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 switch functions.

Note:

Each power supply must be connected to a dedicated power source outlet.

To connect AC power to a QFX5110:

  1. Attach the grounding strap to your bare wrist and to a site ESD point.
  2. Ensure that the power supplies are fully inserted in the chassis and the latches are secure. If only one power supply is installed, ensure that a blank cover panel is installed over the second power supply slot.
  3. Locate the power cord or cords shipped with the switch; the cords have plugs appropriate for your geographical location. See QFX5110 AC Power Specifications.
    Warning:

    Ensure that the power cord does not block access to device components or drape where people can trip on it.

  4. Connect each power supply to the power sources. Insert the coupler end of the power cord into the AC power cord inlet on the AC power supply faceplate.
  5. Push the power cord retainer onto the power cord (see Figure 3).
    Figure 3: Connecting an AC Power Cord to an AC Power Supply in a QFX5110Connecting an AC Power Cord to an AC Power Supply in a QFX5110
      1
    —

    Power cord retainer

    		 
  6. If the AC power source outlet has a power switch, set it to the off (O) position.
    Note:

    The switch powers on as soon as power is provided to the power supply. There is no power switch on the device.

  7. Insert the power cord plug into an AC power source outlet.
  8. If the AC power source outlet has a power switch, set it to the on (|) position.
  9. Verify that the AC and DC LEDs on each power supply are lit green.

    If the amber fault LED is lit, remove power from the power supply, and replace the power supply (see Removing a Fan Module from a QFX5110). Do not remove the power supply until you have a replacement power supply ready: the power supplies or a blank cover panel must be installed in the switch to ensure proper airflow.

    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 a QFX5110

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).

  • 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 Connect the QFX5110 to Earth Ground.

    On DC systems, you can also ground the chassis using the DC protective earthing terminal on the DC power supply as an alternate method. This method is useful if you are unable to access the chassis ground point by using the two-holed grounding lug, see Alternate Method to Ground QFX5110-48S-DC and QFX5110-32Q-DC Systems.

  • Install the power supply in the chassis. For instructions on installing a power supply in a QFX5110, see Installing a Power Supply in a QFX5110.

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)

The QFX5110 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 QFX5110 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).

To connect DC power to a QFX5110:

  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.

    CAUTION:

    You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the DC power input terminals on each power supply.

  3. Install heat-shrink tubing insulation around the power cables.

    To install heat-shrink tubing:

    1. Slide the tubing over the portion of the cable where it is attached to the lug barrel. Ensure that tubing covers the end of the wire and the barrel of the lug attached to it.

    2. Shrink the tubing with a heat gun. Ensure that you heat all sides of the tubing evenly so that it shrinks around the cable tightly.

    Figure 4 shows the steps to install heat-shrink tubing.

    Note:

    Do not overheat the tubing.
    Figure 4: How to Install Heat-Shrink Tubing How to Install Heat-Shrink Tubing
  4. Ensure that the input circuit breaker is open so that the voltage across the DC power source cable leads is 0 V and that the cable leads do not become active while you are connecting DC power.
    Note:

    The V+ terminals are referred to as +RTN, and V– terminals are referred to as –48 V in DC Power Wiring Sequence Warning and DC Power Electrical Safety Guidelines.

  5. Ensure that the power supplies are fully inserted in the chassis.
  6. Remove the terminal block cover. The terminal block cover is a piece of clear plastic that snaps into place over the terminal block (see Figure 5).
  7. Remove the screws on the terminals using the screwdriver. Save the screws.
    Warning:

    Ensure that the power cables do not block access to device components or drape where people can trip on them.

  8. Connect each power supply to the power sources. Secure power source cables to the power supplies by screwing the ring lugs attached to the cables to the appropriate terminals by using the screw from the terminals (see Figure 5 and Figure 6).

    The QFX5110 is designed to operate with a DC power supply that has a single, non-redundant, feed input. For source redundancy, two DC power supplies must be installed in the QFX5110; connect source (A) to one power supply and connect source (B) to the second power supply. This configuration provides the commonly deployed A/B feed redundancy for the system.

    The terminal block of the power supply has four terminals labeled V+, V+, V–, and V– for connecting DC power source cables labeled positive (+) and negative (–). The V+ terminals are shunted internally together, as are the V- terminals.

    CAUTION:

    The connection between each power source and power supply must include a circuit breaker.

    Do not connect two sources to a single power supply because doing so can potentially cause circulating current in feed wires whenever there is any difference in the voltage of the two sources.

    1. Secure the ring lug of the positive (+) DC power source cable to the V+ terminal on the DC power supply.
    2. Secure the ring lug of the negative (–) DC power source cable to the V– terminal on the DC power supply.
    3. Tighten the screws on the power supply terminals until snug using the screwdriver. Do not overtighten; apply between 5 in-lb (0.56 Nm) and 6 in-lb (0.68 Nm) of torque to the screws.
    Figure 5: DC Power Supply Faceplate for a QFX5110DC Power Supply Faceplate for a QFX5110
      1
    —

    Shunt negative input terminals (+RTN)

      5
    —

    Protective earthing terminal

      2
    —

    Shunt positive input terminals (-48V)

      6
    —

    Fault LED

      3
    —

    Terminal block

      7
    —

    Output LED

      4
    —

    Ejector lever

      8
    —

    Input LED

    CAUTION:

    The V+ terminals are shunted internally together, as are the V- terminals. The same polarity terminal can be wired together from the same source to provide an additional current path in a higher power chassis. Do not connect the terminals to different sources.

    Figure 6: Securing Ring Lugs to the Terminals on the QFX5110 DC Power SupplySecuring Ring Lugs to the Terminals on the QFX5110 DC Power Supply
  9. Replace the terminal block cover.
  10. Close the input circuit breaker.
    Note:

    The switch powers on as soon as power is provided to the power supply. There is no power switch on the device.

  11. Verify that the IN and OUT LEDs on the power supply are lit green and are on steadily.

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