Cabling the Modular Switch
4.1 Cabling the Power Supplies
Before you begin, refer to the Arista Networks document Compliance and Safety Guide available at: https://www.arista.com/en/support/product-documentation.
Important! Power down the switch: Remove all power cords from the power inlets.

Mettez le commutateur: Retirez tous les cordons d'alimentation des prises d'alimentation.
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.
Note Many configurations will require additional power supplies.

Nombreuses configurations exigera des alimentations supplémentaires.
Important! All power supply slots must be filled with either a power supply or blank to ensure proper air flow.

Tous les emplacements d'approvisionnement de puissance doivent être remplis avec une alimentation ou vide pour assurer un débit d'air appropriée.
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.
The 7500N chassis requires the connection of at least two operating power supplies in the top row to active circuits.
Each power supply includes a fan that maintains proper power supply temperature and cools the supervisor modules. The appendices display the location of components for all switches described in this guide.
Figure 4-1 shows the supported power supplies for the 7500N family of switches.
Figure 4-1: Supported Power Supplies
 
1
PWR-3KT-AC-Red
       
2
PWR-2700-DC-R
       
3
PWR-3K-DC-Red
       
4.2 Cabling Secondary Ground
Appendix C displays the location of the secondary grounding pads on front panel of the switch chassis. After mounting the switch into the rack, connect at least one of the secondary grounds to the data center ground. After the switch is grounded, ESD wrist straps can be grounded by connecting them to one of the attach points.
Important! Grounding wires and grounding lugs are not supplied.
Wire size should meet local and national installation requirements.
Commercially available 2 or 4 AWG wire is recommended for installations in the U.S.

À la terre et de mise à la terre fils cosses ne sont pas fournis.
Calibre des fils doit satisfaire des exigences de l'installation locale et nationale.
Disponible dans le commerce 2 ou 4 AWG fil est recommandé pour les installations aux États-Unis.
Important! This equipment must be grounded. Never defeat the ground conductor. This unit requires over-current protection.

Cet équipement doit être mis à la terre. Ne jamais modifier le conducteur de terre. Cet appareil nécessite de protection contre les surintensités.
Important! Secondary Grounding wires, lugs and screws (M4 x 0.7) are not supplied.

Secondaire à la terre, câbles, cosses et vis (M4 x 0.7) ne sont pas fournis.
Secondary ground locations on the switches are displayed in Appendix D.
Power down the switch: Remove all power cords from the power inlets.
4.3 Cabling the AC Power Supply
Appendix D displays the rear panel location of power supplies and fabric modules.
The switch uses power cables with IEC-320 C-19 plugs. The accessory kit provides IEC-320 C-19 to C-20 power cables, each two meters long.To insert a power cable, plug the power cables into the inlet.
4.4 Cabling the DC Power Supply
Note The -48V and Battery-Return leads are a pair and should run adjacent to each other and be approximately the same length.

Le - 48V et câbles de batterie-retour sont une paire courir à côté de l'autre et doivent être à peu près la même longueur.
4.4.1 DC Power Supplies
The 7500N Series chassis supports two DC power supplies.
4.4.2 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.
Step 1 Stranded copper wiring is required.
Commercially available 2 to 4 AWG wire is recommended for installations in the U.S.
Wire size should meet local and national installation requirements.
Grounding wires and grounding lugs are not supplied.
Strip the wires to the appropriate length for the lugs.
The wires connecting the DC power supply to the power source must meet the following requirements:
DC Input Wire Size: 2 – 4 AWG (33.6 mm2 to 21.2 mm2).
Primary Ground Wire Size: 2 – 4 AWG (33.6 mm2 to 21.2 mm2) per power supply.
The conductors are copper.
Figure 4-2: Lugs wiring terminations
 
1
Insulated wire
3
-48V + RTN lug
5
1/2”
2
Heat-shrink tubing
4
1/4”
6
5/8”
Figure 4-3: Ground lug wiring termination (PWR-2700W-DC-R)
 
1
Insulated wire
3
5/16” Ø
   
2
Ground lug (right angle)
4
Heat-shrink tubing
   
Note You can also use a 45° angled connector instead of the straight connector shown.
Step 2 Use agency-approved compression (pressure) lugs for wiring terminations with a single 5/16" mounting hole. Two-hole lugs should have 1/4" mounting holes on 5/8" centers.
The PWR-2700W-DC-R ground lug is a right-angle lug. Check the terminations for the appropriate wire size. Use a ground wire of at least 2 – 4 AWG. Use only copper wire.
Step 3 Slip on heat-shrink tubing on the wire ends before assembling the lugs on to the wire.
The lugs must be crimped with the proper tool.
The tubing should extend over the lug’s barrel and the wire's insulator.
Step 4 Shrink the tubing with a heat gun.
4.4.3 PWR-3K-DC-RED Power Supply
Figure 4-4 displays the PWR-3K-DC-RED power supply.
Figure 4-4: PWR-3K-DC-RED power supply
 
1
Status LED
3
Ejector
5
-48V terminal
2
Ground terminal
4
RTN terminal
   
Step 1 Prepare the stranded wiring, see Section 4.4.2
Step 2 Attach the power cable to the supply terminals.
Step 3 Tightening Torque: 2.7 N-m (24 in.-lbs.)
4.5 DC Power Adapter Installation for PWR-2700-DC-R
4.5.1 Connecting the Power Cable Lug to the Terminal Studs
Step 1 Prepare the stranded wiring, see Section 4.4.2.
Step 2 Remove the clear plastic cover protecting the terminal studs on the adapter by lifting the small center tab while sliding the cover off the adapter.
4.5.2 Connecting the Ground to PWR-2700-DC-R Power Supply
The primary ground on the system requires a 2 – 4 AWG 5/16 inch lug per power supply.
Figure 4-5 displays the PWR-2700-DC-R power supply without the DC adapter.
Figure 4-5: DC power supply
 
1
Ground
           
Step 1 Prepare the stranded wiring, see Section 4.4.2.
Step 2 Attach the ground cable to the ground stud.
Step 3 Tightening Torque: 2.7 N-m (24 in.-lbs.)
4.5.3 Connecting the Power Cable Lug to the Terminal Studs
Step 1 Prepare the stranded wiring, see Section 4.4.2.
Step 2 Remove the clear plastic cover protecting the terminal studs on the adapter by lifting the small center tab while sliding the cover off the adapter.
 
1
Plastic lid
2
Center tab
Step 3 Remove the flange locking nuts from each of the terminal studs.
 
1
Flange locking nuts
   
Step 4 Secure each power cable lug to the terminal studs with the flange locking nuts.
Attach the positive (+) DC source power cable lug to the RTN (return) terminal.
Attach the negative (–) DC source power cable lug to the –48V (input) terminal.
Torque the four flange locking nuts to 2.7 N-m (24 in.-lbs.).
 
1
Compression lugs
3
-48V
2
Compression lugs
4
RTN
Step 5 Slide the cover over the terminal studs until it clicks into place.
 
1
Captive screw slots
   
Step 6 Insert the adapter into the DC power supply.
Step 7 Tighten the two captive screws (on the bottom of the adapter) to the power supply module. Torque screws with #2 Posidriv to 2 N-m (17.7 in.-lbs.)
Step 8 Attach the power cable to the DC power source.
Important! Apply the ground connection first during installation and remove last when removing power.

Appliquer le motif connexion tout d'abord pendant l'installation et supprimer dernière lors du retrait de puissance.
4.6 Power Supply Specifications
Table 4-1 shows the power supply specifications for each of the PSUs supported.
 
Table 4-1 Power supply specifications (each PSU)
Power Supply
Maximum output power rating (DC)
Input voltage and frequency
Maximum input current
Input branch circuit protection
PWR-2700-DC-R
2600 W
-48 or -60 V (nominal)
80 A
100 A
PWR-3K-DC-RED
3000 W
-48 or -60 V (nominal)
80 A
100 A
PWR-3KT-AC RED
3000 W
200 to 240 V (nominal)
50 - 60 Hz (nominal)
16 A
20 A
4.7 Power Supply Configurations
Table 4-2 shows the power supply configurations for the modular switches.
 
Table 4-2 Power supply configurations
Modular switch
Recommended number of PSUs (for redundancy)
Number of PSUs shipped in bundle
Minimum number of PSUs required (per power domain)
Maximum number of PSUs supported
Number of power domains
DCS-7504N
4
4
2
4
1
DCS-7508N
6
6
2
8
1
DCS-7512N
8
8
2
12
1
DCS-7516N
12
12
3
20
2
4.7.1 Recommendations for power supply usage
Use separate circuit with required protection for each power supply.
Use the same PSU model when replacing a failed PSU. Check for a suitable alternative if the model is no longer supported or available.
Unless your switch allows for mixing power supplies, do not mix power supply types.
You must populate each power domain with the minimum number of PSUs required. Domains are separate banks of grouped supplies, Ten high and ten low for the 16 slot chassis (Domain 1: PS1 – PS10; domain 2: PS11 – PS20).
Chassis with multiple power domains should have an equal number of supplies in each domain.
For supervisor cooling purposes, all systems require the minimum number of PSUs, as specified in Table 4-2, in the top section behind the supervisors.
For 8- & 12-slot chassis, (grouped power supplies top and bottom) Arista recommends equal number of power supplies in the top and bottom groups.
For the 16-slot chassis with 2 power domains, the power domain with the lowest number of power supplies prescribes the total power available, therefore, Arista recommends equal number of PSUs in each domain.
Valid redundancy configurations for each domain are described in Power Supply Redundancy section.
4.8 Power Supply Redundancy
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.
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.
Most installations will have redundant, dual, independent power feeds.
For the following examples, each power feed originates from a different power provider. Each independent power feed will be referenced as label A and B.
Each supply is wired to one feed, either A, or B.
The recommended installation is to alternate A, B feeds. In a four supply system configuration, you would wire ABAB, left to right.
All power supply slots must be filled with a powered supply (A or B), or a blank (X), or a non-powered power supply.
For supervisor cooling purposes, all systems require a minimum number of operating power supplies (see Table 4-2) at all times in the top half of the chassis. For optimal performance, alternate pairs of power supplies (A and B) evenly from top to bottom (8 or more slot chassis).
Valid examples include:
AXAX Minimum Configuration supported, 2+0 (non-redundant)
ABAB 2+2 redundant
ABAB (Upper), AB (Lower) 3+3 redundancy
ABAB (Upper), ABAB (Lower) 4+4 redundancy
ABXXAB (Upper), ABXXAB (Lower) 4+4 redundancy (12-slot chassis)
ABABAB (Upper), ABABAB (Lower) 6+6 redundancy
AAAX for 3+0 or 2+1 redundancy, with the X anywhere
AAAA for 4+0 or 3+1 redundancy
ABABAB (Upper), ABABAB (Lower) 6+6 redundancy (12-Slot Chassis)
XABAX/XBABX (Upper), XABAX/XBABX (Lower) 6+6 redundancy (16-slot chassis)
BABAB/ABABA (Upper), BABAB/ABABA (Lower) 10+10 redundancy (16-slot chassis)
Each power supply includes a fan that maintains proper power supply temperature and cools the supervisor modules. The following appendices display the location of the following component on all switches described in this guide.
Appendix C displays the front panel location of the supervisor modules.
Appendix D displays the rear panel location of power supplies and fabric modules.
Important! This unit requires over-current protection.

Cet appareil nécessite de protection contre les surintensités.
Important! Unused slots must be occupied or covered with a blank to ensure proper airflow through the chassis.

Les emplacements inutilisés doivent être occupés ou recouvert d'un blanc pour assurer la bonne circulation d'air dans le châssis.
4.9 Connecting Supervisor Cables
Supervisor modules contain console, management, and USB ports. Figure 4-6 and Figure 4-7 displays port locations on the supervisors. Refer to the chassis specification in Table 4-3 for additional information.
Figure 4-6: Supervisor DCS-7500E-SUP
 
1
Status LED
5
Fan module status LED
9
Active LED
2
USB ports
6
Fabric module status LED
   
3
Ethernet management ports
7
Linecard status LED
   
4
Serial console port
8
Power supply status LED
   
 
Figure 4-7: Supervisor DCS-7500E-SUP 2
 
1
Status LED
5
Clock input port (optional)
9
Power supply status LED
2
USB ports
6
Fan module status LED
10
Active LED
3
Ethernet management ports
7
Fabric module status LED
   
4
Serial console port
8
Linecard status LED
   
 
Figure 4-8: Supervisor DCS-7516-SUP
 
1
Status LED
5
Clock input port (optional)
9
Power supply status LED
2
USB ports
6
Fan module status LED
10
Active LED
3
Ethernet management ports
7
Fabric module status LED
   
4
Serial console port
8
Linecard status LED
   
 
 
Console (Serial) Port: Connect to a PC with RJ-45 to DB-9 serial adapter cable. Default switch settings include:
9600 baud
No flow control
1 stop bit
No parity bits
8 data bits
The DCS-7516-SUP supervisor cards must be installed in one of the two slots designated for them in the DCS-7516N switch as shown in Figure 4-9.
Note Do not insert a line card into either of the slots 1 and 2, designated for a supervisor card. This could damage the modular switch. Slots for the line cards are numbered 3 through 18.
Figure 4-9: DCS 7516N Supervisor Slots
 
1
Supervisor slot 1
2
Supervisor slot 2
Table 4-3 RJ-45 to DB-9 Connections
 
RJ-45
DB-9
 
RJ-45
DB-9
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
Ethernet management port: Connect to 10/100/1000 management network with RJ-45 cable.
USB Port: May be used for software or configuration updates.
Clock Input Port: Port type is MCX connector, 2-5.5V, 50 ohm termination.
4.10 Connecting Line Card Modules and Cables
Install required SFP, SFP+, QSFP+, QSFP100 and CFP2 optic modules in line card module ports ( Figure 4-10).
Figure 4-10: SFP or SFP+ ports
Connect cables as required to line card module ports or fixed MPO ports. Supervisor and line card module ejectors on the front of the chassis assist with cable management.
Caution Excessive bending can damage interface cables, especially optical cables.

Flexion excessive peut endommager les câbles d'interface, en particulier les câbles optiques.
 
Note You must ensure that any open slots for modules, power supplies, etc. are covered by the appropriate “blank” plates. Check with your local Arista Networks representative if you have questions.