Cabling the Switch

Note: Arista fixed switches take approximately 5 to 10 minutes to boot completely.

Grounding the Switch

After mounting the switch into the rack, connect the switch to the data center ground.

Figure 1 displays the location of the grounding pads located on the bottom corners of the rear panel for the models that have no management ports on the rear panel. Figure 2 displays the location of the grounding pads on the rear panel for models that have management ports on the rear panel. There are threaded holes under the sticker on the right (next to PS2) that warns about “1 min”.Figure 3 displays the location of the grounding assembly on the rear panel for DCS-7280CR3-32P4.


Important: Grounding wires and grounding lugs (M4 x 0.7) are not supplied. Wire size should meet local and national installation requirements. Commercially available 6 AWG wire is recommended for installations in the US.


À la terre et de mise à la terre fils cosses (M4 x 0.7) ne sont pas fournis. Calibre des fils doit satisfaire des exigences de l’installation locale et nationale. Disponible dans le commerce 6 fils AWG est recommandé pour les installations aux États-Unis.

Figure 1. Earth Grounding Pad Sockets for Models without Management Ports on the Rear Panel

1 Earth grounding pads
Figure 2. Earth Grounding Pad Sockets for Models with Management Ports on the Rear Panel

1 Earth grounding pads
Figure 3. Earth Grounding Adapter for DCS-7280CR3-32P4

Grounding Adapter Assembly (KIT-GND-EXT-1RU)

The following steps assemble and attach a grounding assembly to the chassis before mounting it into the rack.

The following switches support the external grounding kit. Identify the location for attaching the adapter. As shown in the following example, the attachment point is on the bottom of the chassis in some cases.


Table 1. Grounding Kit Adapter Support
Switch Grounding Kit Adapter
7280PR3-24 KIT-GND-EXT-1RU
7280DR3-24 KIT-GND-EXT-1RU
7280CR3-32P4 KIT-GND-EXT-1RU
7280DR3-32P4 KIT-GND-EXT-1RU

Figure 4 shows the exploded and assembled views.

Figure 4. Earth Grounding Adapter Assembly for DCS-7280CR3-32P4
  1. Identify all the components to be assembled:

    Note: The chassis is shown upside down in the figure above.
    • 1x Grounding adapter
      • 1x Grounding bracket
        • 2x Flat-head screws (Phillips,M4 x 5.00 long, stainless steel)
        • 2x Hex nuts (#10-32, Serrated Flange, stainless steel)
        • 1x Grounding lug (Copper, 2-hole, 6 AWG, straight barrel)
  2. Insert the grounding adapter through the holes in the grounding bracket.
  3. Insert the ground lug on to the grounding adapter studs and fasten using the hex nuts to form the grounding assembly.
  4. With the chassis on its top on a flat surface, attach the grounding assembly to the chassis using the flat head screws.
  5. Turn the chassis over before mounting it into a rack and connecting cables.

Connecting Power Cables

Power cords are optional and must be ordered separately. You must use an approved power cord compliant with local and national electrical codes or order one from Arista for use with the device.

Important: Installation of this equipment must comply with local and national electrical codes. If necessary, consult with the appropriate regulatory agencies and inspection authorities to ensure compliance.


Installation de cet équipement doit être conformes aux codes électriques locaux et nationaux. Si nécessaire, consulter les organismes de réglementation appropriés et des autorités de contrôle pour assurer la conformité.

The switch operates with two installed power supplies. At least one power supply must connect to a power source. Two circuits provide redundancy protection. Rear Panel displays the location of the power supplies on the rear panel of the switch.

Important: Read all installation instructions before connecting the system to the power source.


Lire toutes les instructions d’installation avant de brancher le système à la source d’alimentation.
  • Non-Redundant Configuration: Connect power to either of the two power supplies.
  • Redundant Power Supply Configuration: Connect power to both power supplies.
  • Power down the Switch: Remove all power cords and wires from the power supplies.
    Important: This equipment must be grounded. Never defeat the ground conductor.


    Cet équipement doit être mis à la terre. Ne jamais modifier le conducteur de terre.

    Important: This unit requires overcurrent protection.


    Cet appareil requiert une protection contre les surintensités.

AC Power Supplies

The following AC power supplies are supported.

PWR-500AC PWR-745AC PWR-1011-AC
PWR-511-AC PWR-747AC PWR-1511-AC

Figure 5 displays an AC power supply, including the power socket on the left side of the module. The AC power supply connects to a circuit that provides the required power, as specified by Table 4.

Note: Several PSUs support both forward and reverse airflow directions.
Figure 5. AC Power Supply Example

The power supplies require power cables that comply with IEC-320 and have a C14 connector. The accessory kit provides two IEC-320 C13 to C14 power cables.

DC Power Supplies

The following DC power supplies are supported.

Note: Several PSUs support both forward and reverse airflow directions.
PWR-500-DC PWR-1900-DC PWR-1511-DC
PWR-511-DC PWR-1011-DC  

The following image displays examples of DC power supplies.

Figure 6. DC Power Supply Examples

Important: A disconnect device must be provided as part of the installation .


Un dispositif de sectionnement doit être fourni dans le cadre de l'installation.

Important: Ensure power is removed from DC circuits before performing any installation actions. Locate the disconnect device, circuit breakers or fuses on DC power lines servicing the circuits. Turn off the power line circuits or remove the fuses.


Pouvoir assurer qu'il est retiré de circuits DC avant d'effectuer des actions d'installation . Localiser les disjoncteurs ou des fusibles sur les lignes de courant continu desservant les circuits. Coupez les circuits de lignes d'alimentation ou retirer les fusibles.

Important: Wire size must comply with local and national requirements and electrical codes. Use only copper wire.


Le calibre du fil doit être conforme aux exigences locales et nationales et les codes électriques. Utiliser du fil de cuivre.

Important: Apply ground connection to the switch first during installation and remove last when removing power.


Appliquer connexion à la terre à l'interrupteur premier lors de l'installation et de supprimer la dernière alimentation lors du débranchement.

Wire and Lug Preparation

Before performing any installation actions, ensure power is removed from DC circuits by turning off the power line servicing the circuits. Prepare the stranded wiring before you begin a DC power installation.

Note: Stranded copper wiring is required and should meet local and national installation requirements. Wires and grounding lugs are not supplied.
  1. Attach an ESD grounding strap.
  2. Prepare the stranded copper wiring for the power supply to be used. Table 4 provides wiring, lug, and tightening torque information for the power supplies covered in this guide.
    Table 2. Wiring, Lug, and Tightening Torques for DC PSUs
    PSU Wire Size(1) Lug Type(2) Tightening Torque
    (AWG) (mm2) N•m in.•lbs.
    PWR-500-DC 14 or larger 2.0 or larger ring or spade/fork 1.0 9
    PWR-511-DC 12 - 14 4.0 - 2.5   1.0 9
    PWR-1900-DC 4 - 6 21.2 - 13.3   2.7 24
    PWR-1011-DC 6 - 8 16.0 - 10.0   2.7 24
    PWR-1511-DC 4 - 6 25.0 - 16.0   2.7 24
  1. Unless otherwise noted, wire size applies to -48V, Battery return, and Protective earth wires.
  2. Unless otherwise noted, twin #10 studs spaced for dual-hole lug with 5/8" hole spacing.
  3. Strip the wires to the appropriate length for the lugs to be used.
  4. Use agency-approved compression (pressure) lugs for wiring terminations.
  5. Slip on heat-shrink tubing on the wire ends before assembling the lugs on to the wire.
  6. Crimp the lugs with the proper tool, and ensure that the tubing extends over the barrel of the lugs and the insulation on the wires (Lug Preparation).
  7. Shrink the tubing with a heat gun.
Figure 7. Lug Preparation
1 Insulated wire 3 Lug B 1/2”
2 Heat-shrink tubing A 1/4” C 5/8”
Note: Dimension B is the width of the lug (not visible on the right angle lug).

Connecting a DC Power Supply to Power Source

Figure 8 displays an example of connecting a PSU. To connect a DC power supply to a power source, perform the following:

  1. Prepare the stranded wiring (Wire and Lug Preparation).
  2. Attach the appropriate lugs to the source DC wires.
  3. Connect the DC-input wires to the appropriate terminals using the specified torque (Table 4) in the following order.
    Note: Remove terminal covers as needed.
    1. Ground wire to the Protective Earth (PE ) terminal.
    2. Negative source DC cable to the negative (- / -48V) terminal.
    3. Positive (+) source DC cable to the positive (+ / Rtn) terminal.
  4. Replace the terminal covers as required.
    Figure 8. DC PSU Connection Example

Connecting Serial and Management Cables

The accessory kit includes the following cables:
  • RJ-45 to DB-9 serial adapter cable.
  • RJ-45 Ethernet cable.

Table 3 lists the pin connections of the RJ-45 to DB-9 adapter cable.

Table 3. RJ-45 to DB-9 Connections






RTS 1 8 CTS   GND 5 5 GND
DTR 2 6 DSR   RXD 6 3 TXD
TXD 3 2 RXD   DSR 7 4 DTR
GND 4 5 GND   CTS 8 7 RTS
Note: RJ-45 to DB-9 connections: For models with a console management port on the rear panel, RJ-45 pin 1 (RTS) is connected to RJ-45 pin 8 (CTS); RJ-45 pin 2 (DTR) and RJ-45 pin 7 (DSR) are not electrically connected to any signal.

For most models, the front panel contains the console, management, and USB ports. The front panel ports display the ports on the front panel of the DCS-7050QX-32S switch. The rear panel ports display the ports on rear panel of the DCS-7280SR-48C6 switch. The front panel and rear panel display all switches covered by this guide.

Figure 9. Front Panel Ports

1 USB port 3 Console serial port
2 Ethernet management port    
Figure 10. Rear Panel Ports

1 System status LED 3 Activity status LED 5 USB port
2 Ethernet management port 4 Console serial port 6 Link status LED
Connect the front or rear panel ports as follows:
  • Console (Serial) Port: Connect to a PC with the RJ-45 to DB-9 serial adapter cable. The switch uses the following default settings:
    • 9600 baud
    • No flow control
    • 1 stop bit
    • No parity bits
    • 8 data bits
  • Ethernet Management Port: Connect to 10/100/1000 management network with RJ-45 Ethernet cable.
  • USB Port: The USB port may be used for software or configuration updates.
    CAUTION: Excessive bending can damage interface cables, especially optical cables.

    Flexion excessive peut endommager les câbles d’interface, notamment des câbles optiques.