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Connecting Earth Ground to a QFX3500 Device

To meet safety and electromagnetic interference (EMI) requirements and to ensure proper operation, you must connect the QFX3500 device to earth ground before you connect it to power.

For installations that require a separate grounding conductor to the chassis, you must attach a protective earthing terminal bracket on the QFX3500 device left front mounting bracket to connect to the earth ground (see Figure 1).

Before you connect earth ground to the protective earthing terminal of a QFX3500 device, ensure that a licensed electrician has attached an appropriate grounding lug to the grounding cable.

CAUTION:

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

Note:

Mount your device in the rack or cabinet before attaching the grounding lug to the device. See Mounting a QFX3500 Device in a Rack or Cabinet.

Ensure that you have the following parts and tools available:

  • Protective earthing terminal bracket—This L-shaped bracket attaches to a post on the QFX3500 device left front mounting bracket, providing a protective earthing terminal for the device. This bracket is provided in the accessory kit.

  • Grounding cable for your QFX3500 device—The grounding cable must be 14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code.

  • Grounding lug for your grounding cable—The grounding lug required is a Panduit LCD10-10A-L or equivalent. This grounding lug is provided in the accessory kit.

  • Three M4 hex nuts with integrated washers—One nut and washer are required to secure the grounding lug bracket to the left front mounting bracket, and two nuts and washers are used to secure the grounding lug to the grounding lug bracket protective earthing terminal. Four nuts are provided in the accessory kit.

  • 7-mm wrench or socket with driver to attach all three nuts.

An AC-powered QFX3500 device chassis gains additional grounding when you plug the power supply in the device into a grounded AC power outlet by using an AC power cord appropriate for your geographical location. See AC Power Cord Specifications for a QFX Series Device.

To connect earth ground to a QFX3500 device:

  1. Secure the provided protective earthing terminal bracket to the threaded post on the QFX3500 device left front mounting bracket with the nut provided. The posts on the protective earthing terminal bracket should point to the left. See Figure 1.
    Figure 1: Connecting a Grounding Cable to a QFX3500 DeviceConnecting a Grounding Cable to a QFX3500 Device
  2. Connect one end of the grounding cable to a proper earth ground, such as the rack in which the device is mounted.
  3. Place the grounding lug attached to the grounding cable over the protective earthing terminal on the protective earthing terminal bracket.
  4. Secure the grounding lug to the protective earthing terminal with two nuts.
  5. 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.

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