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Connecting AC Power to a QFX5100 Device

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.


    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 a QFX5100 Device. 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 AC Power Supply for a QFX5100 Device).

  • Install the power supply in the chassis. For instructions on installing a power supply in a QFX5100 device, see Installing a Power Supply in a QFX5100 Device.

The QFX5100 is shipped from the factory with two 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.


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

To connect AC power to a QFX5100 device:

  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 a that 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 AC Power Cord Specifications for a QFX Series Device.

    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 1 and Figure 2).
    Figure 1: Connecting an AC Power Cord to an AC Power Supply in a 1 U QFX5100 DeviceConnecting an AC Power Cord to an AC Power Supply in a 1 U QFX5100 Device
    Power cord retainer
    Figure 2: Connecting an AC Power Cord to an AC Power Supply in a 2 U QFX5100 DeviceConnecting an AC Power Cord to an AC Power Supply in a 2 U QFX5100 Device
  6. If the AC power source outlet has a power switch, set it to the OFF (O) position.

    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 Power Supply from a QFX5100 Device ). 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.


    Replace a failed power supply with a blank panel or new power supply within 1 minute of removal to prevent chassis overheating.


    A system reboot with Routing Engine FPGA version 7.1 might not successfully boot the Junos OS software. In case of a system reboot failure, you need to power cycle the switch. To check the current FPGA version, issue the show chassis firmware command.