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QFX5110 Site Guidelines and Requirements

QFX5110 Environmental Requirements and Specifications

The switch must be installed in a rack or cabinet. It must be housed in a dry, clean, well-ventilated, and temperature-controlled environment.

Follow these environmental guidelines:

  • The site must be as dust-free as possible, because dust can clog air intake vents and filters, reducing the efficiency of the switch cooling system.

  • Maintain ambient airflow for normal switch operation. If the airflow is blocked or restricted, or if the intake air is too warm, the switch might overheat, leading to the switch temperature monitor shutting down the device to protect the hardware components.

Table 1 provides the required environmental conditions for normal switch operation for all QFX5110 models.

Table 1: QFX5110 Environmental Tolerances




No performance degradation to 6562 feet (2000 meters)

Relative humidity

Normal operation ensured in relative humidity range of 5% through 90%, noncondensing

  • Short-term operation ensured in relative humidity range of 5% through 93%, noncondensing


    As defined in NEBS GR-63-CORE, Issue 3, short-term events can be up to 96 hours in duration but not more than 15 days per year.


  • Normal operation ensured in temperature range of 32° F through 104° F (0° C through 40° C)

  • Nonoperating storage temperature in shipping container: –40° F through 158° F (–40° C through 70° C)


Designed to comply with Zone 4 earthquake requirements per NEBS GR-63-CORE, Issue 3.


Install QFX Series devices only in restricted areas, such as dedicated equipment rooms and equipment closets, in accordance with Articles 110-16, 110-17, and 110-18 of the National Electrical Code, ANSI/NFPA 70.

General Site Guidelines

Efficient device operation requires proper site planning and maintenance. It also requires proper layout of the equipment, rack or cabinet, and wiring closet.

To plan and create an acceptable operating environment for your device and prevent environmentally caused equipment failures:

  • Keep the area around the chassis free from dust and conductive material, such as metal flakes.

  • Follow prescribed airflow guidelines to ensure that the cooling system functions properly. Ensure that exhaust from other equipment does not blow into the intake vents of the device.

  • Follow the prescribed electrostatic discharge (ESD) prevention procedures to prevent damaging the equipment. Static discharge can cause components to fail completely or intermittently over time.

  • Install the device in a secure area, so that only authorized personnel can access the device.

Site Electrical Wiring Guidelines

Table 2 describes the factors you must consider while planning the electrical wiring at your site.


You must provide a properly grounded and shielded environment and use electrical surge-suppression devices.

Avertissement Vous devez établir un environnement protégé et convenablement mis à la terre et utiliser des dispositifs de parasurtension.

Table 2: Site Electrical Wiring Guidelines

Site Wiring Factor


Signaling limitations

If your site experiences any of the following problems, consult experts in electrical surge suppression and shielding:

  • Improperly installed wires cause radio frequency interference (RFI).

  • Damage from lightning strikes occurs when wires exceed recommended distances or pass between buildings.

  • Electromagnetic pulses (EMPs) caused by lightning damage unshielded conductors and electronic devices.

Radio frequency interference

To reduce or eliminate RFI from your site wiring, do the following:

  • Use a twisted-pair cable with a good distribution of grounding conductors.

  • If you must exceed the recommended distances, use a high-quality twisted-pair cable with one ground conductor for each data signal, when applicable.

Electromagnetic compatibility

If your site is susceptible to problems with electromagnetic compatibility (EMC), particularly from lightning or radio transmitters, seek expert advice.

Strong sources of electromagnetic interference (EMI) can cause:

  • Destruction of the signal drivers and receivers in the device,

  • Electrical hazards as a result of power surges conducted over the lines into the equipment.

QFX5110 Chassis Grounding Cable and Lug Specifications

To ground a QFX5110, connect a grounding cable to earth ground and attach it to the chassis grounding points. See Connect the QFX5110 to Earth Ground. However if you are unable to access the chassis grounding point on a DC system by using the two-holed grounding lug, you can ground the chassis using the DC protective earthing terminal on the DC power supply, see Alternate Method to Ground QFX5110-48S-DC and QFX5110-32Q-DC Systems.


To comply with GR-1089 requirements, all intra-building copper cabling used for SFP+ and QSFP+ ports must be shielded and grounded at both ends.


Before switch installation begins, a licensed electrician must attach a cable lug to the grounding cables that you supply. See Connect the QFX5110 to Earth Ground. A cable with an incorrectly attached lug can damage the switch.

Before connecting the switch to earth ground, review the following information:

  • The grounding lug required is a Panduit LCD10-10A-L or equivalent (not provided). The recommended grounding lug accommodates 14–10 AWG (2–5.3 mm²) stranded wire. If you are using the alternate method of grounding the chassis on a QFX5110-48S or QFX5110-32Q DC system, the recommended grounding cable is 12 AWG (2.5 mm²) standard wire, 90° C wire or heavier.

  • The grounding cable must be 14 AWG (2 mm²), minimum 60° C wire, or as permitted by the local code (not provided).

QFX5110 Clearance Requirements for Airflow and Hardware Maintenance

When planning the site for installing a QFX5110, you must allow sufficient clearance around the installed chassis (see Figure 1).

Figure 1: Clearance Requirements for Airflow and Hardware Maintenance for a QFX5110Clearance Requirements for Airflow and Hardware Maintenance for a QFX5110
  • For the cooling system to function properly, the airflow around the chassis must be unrestricted. See QFX5110 Cooling System and Airflow Description for more information about the airflow through the chassis.

  • If you are mounting a QFX5110 in a rack with other equipment, ensure that the exhaust from other equipment does not blow into the intake vents of the chassis.

  • Leave at least 24 in. (61 cm) both in front of and behind the QFX5110. For service personnel to remove and install hardware components, you must leave adequate space at the front and back of the switch. NEBS GR-63 recommends that you allow at least 30 in. (76.2 cm) in front of the rack or cabinet and 24 in. (61 cm) behind the rack or cabinet.

QFX5110 Chassis Physical Specifications

The QFX5110 models are rigid sheet-metal structures that houses the hardware components. Table 3 summarizes the physical specifications of the QFX5110.

Table 3: Physical Specifications for the QFX5110

Product SKU






1.72 in. (4.3 cm)

17.36 in. (44.1 cm)

20.48 in. (52.02 cm) excluding fan and power supply handles

23 lbs (10.43 kg) with 2 power supplies


1.72 in. (4.3 cm)

17.36 in. (44.1 cm)

20.48 in. (52.02 cm) excluding fan and power supply handles

24.6 lbs (11.16 kg) with 2 power supplies

QFX5110 Rack Requirements

QFX5110 switches are designed to be installed on four-post racks.

Rack requirements consist of:

  • Rack type

  • Mounting bracket hole spacing

  • Rack size and strength

Table 4 provides the rack requirements and specifications for the QFX5110.

Table 4: Rack Requirements for the QFX5110

Rack Requirement


Rack type

Use a four-post rack that provides bracket holes or hole patterns spaced at 1 U (1.75 in. or 4.45 cm) increments and that meets the size and strength requirements to support the weight.

A U is the standard rack unit defined in Cabinets, Racks, Panels, and Associated Equipment (document number EIA-310–D) published by the Electronics Industry Association.

Mounting bracket hole spacing

The holes in the mounting brackets are spaced at 1 U (1.75 in. or 4.45 cm), so that the switch can be mounted in any rack that provides holes spaced at that distance.

Rack size and strength

  • Ensure that the rack complies with the standards for a 19-in. or 23-in. rack as defined in Cabinets, Racks, Panels, and Associated Equipment (document number EIA-310–D) published by the Electronics Industry Association.

  • A 600-mm rack as defined in the four-part Equipment Engineering (EE); European telecommunications standard for equipment practice (document numbers ETS 300 119-1 through 119-4) published by the European Telecommunications Standards Institute.

    The horizontal spacing between the rails in a rack that complies with this standard is usually wider than the device's mounting brackets, which measure 19 in. (48.26 cm) from outer edge to outer edge. Use approved wing devices to narrow the opening between the rails as required.

  • Ensure that the rack rails are spaced widely enough to accommodate the switch chassis’ external dimensions. The outer edges of the front-mounting brackets extend the width to 19 in. (48.26 cm).

  • For four-post installations, the front and rear rack rails must be spaced between 23.5 in. (59.7 cm) to 30.6 in. (77.7 cm) front-to-back.

  • The rack must be strong enough to support the weight of the switch.

  • Ensure that the spacing of rails and adjacent racks allows for proper clearance around the switch and rack.

Rack connection to building structure

  • Secure the rack to the building structure.

  • If earthquakes are a possibility in your geographical area, secure the rack to the floor.

  • Secure the rack to the ceiling brackets as well as wall or floor brackets for maximum stability.