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Connecting the EX9251 to Power

Connect Earth Ground to an EX Series Switch

To ensure proper operation and to meet safety and electromagnetic interference (EMI) requirements, you must connect an EX Series switch to earth ground before you connect power to the switch. You must use the protective earthing terminal on the switch chassis to connect the switch to earth ground (see Figure 2).

You must install the EX Series switch in a restricted–access location and ensure that the chassis is always properly grounded. EX Series switches have a two–hole protective grounding terminal provided on the chassis. See Table 1 for the location of the earthing terminals on various EX Series switches. We recommend that you use the protective grounding terminal as the preferred method for grounding the chassis regardless of the power supply configuration. However, if additional grounding methods are available, you can also use those methods. For example, you can use the grounding wire in the power cord of an AC power supply or use the grounding terminal or lug on a DC power supply. This system was tested to meet or exceed all applicable EMC regulatory requirements with the two-hole protective grounding terminal connected correctly.

Ensure that a licensed electrician has attached an appropriate grounding lug to the grounding cable you supply. Using a grounding cable with an incorrectly attached lug can damage the switch.

Parts and Tools Required for Connecting an EX Series Switch to Earth Ground

Before you begin connecting an EX Series switch to earth ground, ensure you have the parts and tools required for your switch.

Table 1 lists the earthing terminal location, grounding cable and lug specifications, and parts needed for connecting an EX Series switch to earth ground.

Table 1: Parts Required for Connecting an EX Series Switch to Earth Ground

Switch

Earthing Terminal Location

Grounding Cable Requirements

Grounding Lug Specifications

Screws and Washers

Additional Information

EX2200

Rear panel of the chassis

14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code

Panduit LCC10-14BWL or equivalent—

not provided

  • Two 10-32 x .25 in. screws with #10 split-lock washer—

    not provided

  • Two #10 flat washers—not provided

 

EX2300-C

Rear panel of the chassis

14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code

Panduit LCC10-14AW-L or equivalent—

not provided

  • Two 10-32 x .25 in. screws with #10 split-lock washer—

    not provided

  • Two #10 flat washers—not provided

 

EX2300

Rear panel of the chassis

  • EX2300 switches except EX2300-24MP and EX2300-48MP models—14 AWG (2 mm²), minimum 90°C wire, or as permitted by the local code

  • EX2300-24MP and EX2300-48MP models—14-10 AWG STR (2.5-6 mm²), 12-10 AWG SOL (4-6 mm²) minimum 90°C wire, or as permitted by the local code—not provided

  • EX2300 switches except EX2300-24MP and EX2300-48MP models—Panduit LCC10-14AW-L or equivalent—not provided

  • EX2300-24MP and EX2300-48MP models—Panduit LCA10-10L or equivalent—not provided

  • EX2300 switches except EX2300-24MP and EX2300-48MP models

    • Two 10-32 x .25 in. screws with #10 split-lock washer—not provided

    • Two #10 flat washers—not provided

  • EX2300-24MP and EX2300-48MP models

    • One Pan Phillips M 4 x 6 mm Nickel plated screw—provided

 

EX3200, EX3300, and EX3400

Rear panel of the chassis

14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code

Panduit LCC10-14BWL or equivalent—

not provided

  • Two 10-32 x .25 in. screws with #10 split-lock washer—

    not provided

  • Two #10 flat washers—

    not provided

For EX3200 Switches, see Special Instructions to Follow Before Connecting Earth Ground to an EX Series Switch.

EX4200, EX4500, and EX4550

Left side of the chassis

14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code

Panduit LCC10-14BWL or equivalent—

not provided

  • Two 10-32 x .25 in. screws with #10 split-lock washer—

    not provided

  • Two #10 flat washers—

    not provided

See Special Instructions to Follow Before Connecting Earth Ground to an EX Series Switch.

EX6210

Rear panel of the chassis (on lower left side)

The grounding cable must be the same gauge as the power feed cables and as permitted by the local code.

Panduit LCD2-14A-Q or equivalent

—provided

  • Two ¼ -20 x 0.5 in. screws with #¼” split-washer

    —provided

  • Two #¼” flat washers—

    provided

 

EX8208

Left side of the chassis

6 AWG (13.3 mm²), minimum 90° C wire, or as permitted by the local code

Panduit LCD2-14A-Q or equivalent

—provided

  • Two ¼ -20 x 0.5 in. screws with #¼” split-washer

    —provided

  • Two #¼” flat washers—

    provided

 

EX8216

Two earthing terminals:

  • Left side of the chassis

  • Rear panel of the chassis

Note:

You must use only one of the two protective earthing terminals.

2 AWG (33.6 mm²), minimum 90° C wire, or as permitted by the local code

Panduit LCD2-14A-Q or equivalent

—provided

  • Two ¼ -20 x 0.5 in. screws with #¼” split-washer

    —provided

  • Two #¼” flat washers—

    provided

 

EX9204, EX9208, and EX9214

Rear panel of the chassis

One 6 AWG (13.3 mm²), minimum 90° C wire, or one that complies with the local code

Thomas& Betts LCN6-14 or equivalent—

provided

  • Two ¼ -20 x 0.5 in. screws with #¼” split-washer—

    provided

  • Two #¼” flat washers—

    provided

See Grounding Cable and Lug Specifications for EX9200 Switches.

EX9251

Rear panel of the chassis

12 AWG (2.5 mm²), minimum 90° C wire, or one that complies with the local code—

not provided

Panduit LCD10-10A-L or equivalent—

not provided

Two 10-32 screws—

provided

See Grounding Cable and Lug Specifications for EX9200 Switches.

EX9253

Right side of the chassis

14-10 AWG (2-5.3 mm²), minimum 90° C wire, or one that complies with the local code—

not provided

Panduit LCD10-14B-L or equivalent—

provided

Two M5 Pan Head screws—

provided

 

Tools required for connecting an EX Series switch to earth ground:

  • An electrostatic discharge grounding strap (provided)

  • A Phillips (+) number 2 screwdriver to tighten the screws.

An AC–powered EX Series switch gains additional grounding when you plug the power supply in the switch into a grounded AC power outlet by using an AC power cord appropriate for your geographical location.

Special Instructions to Follow Before Connecting Earth Ground to an EX Series Switch

Table 2 lists the special instructions that you might need to follow before connecting earth ground to a switch.

Table 2: Special Instructions to Follow Before Connecting Earth Ground to an EX Series Switch

Switch

Special Instructions

EX3200 and EX4200

Some early variants of EX3200 and EX4200 switches for which the Juniper Networks model number on the label next to the protective earthing terminal is from 750-021xxx through 750-030xxx require 10-24x.25 in. screws.

EX4200, EX4500, and EX4550

If you plan to mount your switch on four posts of a rack or cabinet, mount your switch in the rack or cabinet before attaching the grounding lug to the switch.

Note:

The protective earthing terminal on switches mounted on four posts of a rack is accessible through the slot on the left rear bracket only if the rack is 27.5 in. (69.85 cm) through 30.5 in. (77.47 cm) deep for a switch mounted flush with the rack front and 29.5 in. (74.93 cm) through 32.5 in. (82.55 cm) deep for a switch mounted 2 in. (5.08 cm) recessed from the rack front. See Figure 1.

Figure 1: Connecting the Grounding Lug to a Switch Mounted on Four Posts of a RackConnecting the Grounding Lug to a Switch Mounted on Four Posts of a Rack
  1

Protective earthing terminal

  3

Grounding lug

  2

Side mounting-rail

  4

Rear mounting-blade

Note:

The brackets must be attached to the chassis before the grounding lug is attached. (The brackets are shown pulled away from the chassis so that the protective earthing terminal is seen.)

Connecting Earth Ground to an EX Series Switch

To connect earth ground to an EX Series switch:

  1. Verify that a licensed electrician has attached the cable lug to the grounding cable.

  2. Connect one end of the grounding cable to a proper earth ground, such as the rack in which the switch is mounted.

  3. Attach an ESD grounding strap to your bare wrist, and connect the strap to the ESD grounding point on the switch.

  4. Place the grounding lug attached to the grounding cable over the protective earthing terminal. See Figure 2.

    Figure 2: Connecting a Grounding Cable to an EX Series SwitchConnecting a Grounding Cable to an EX Series Switch
  5. Secure the grounding lug to the protective earthing terminal with the washers and screws.

  6. Dress the grounding cable and ensure that it does not touch or block access to other switch components and that it does not drape where people could trip over it.

Connecting AC Power to an EX9251 Switch and Powering on the Switch

Before you begin to connect power to the switch:

Ensure that you have the following parts and tools available to connect power to the switch and to power it on:

You can install up to two AC power supplies in an EX9251 switch. The AC power supply in an EX9251 switch is a hot-removable and hot-insertable field-replaceable unit (FRU). You can remove and replace it while the switch is running without turning off power to the switch or disrupting switching functions. The power supplies install in the slots on the rear panel of the chassis.

CAUTION:

Do not mix AC and DC power supplies in the same chassis.

Note:

Each power supply must be connected to a dedicated AC power feed with a dedicated customer-site circuit breaker. We recommend that you use a dedicated customer-site circuit breaker rated for 20 A (110 VAC) or 16 A (220 VAC) minimum, or as required by local code.

To connect AC power to an EX9251 switch (see Figure 5):

  1. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
  2. Ensure that the power supply is fully inserted and latched securely in the chassis. See Installing an AC Power Supply in an EX9251 Switch.
  3. If the AC power source outlet has a power switch, set it to the off position.
  4. Push the end of the AC power cord retainer strip into the AC power cord retainer port (see Figure 3) next to the inlet on the power supply faceplate until it snaps into place. Ensure that the loop in the retainer strip faces toward the power cord.
    Figure 3: Power Cord Retainer Port on the AC Power Supply FaceplatePower Cord Retainer Port on the AC Power Supply Faceplate
      1

    Handle

      4

    Fault LED

      2

    Input status LED

      5

    Ejector lever

      3

    Output status LED

      6

    AC power cord retainer port

    Figure 4 shows the power cord retainer installed on the AC power supply.

    Figure 4: Power Cord Retainer Installed on the AC Power SupplyPower Cord Retainer Installed on the AC Power Supply
      1

    Handle

      4

    Fault LED

      2

    Input status LED

      5

    AC power cord retainer

      3

    Output status LED

      6

    Ejector lever

  5. Press the small tab on the retainer strip to loosen the loop. Slide the loop until you have enough space to insert the power cord coupler into the inlet.
  6. Insert the power cord plug firmly into the power cord inlet.
  7. Slide the loop toward the power supply until it is snug against the base of the coupler.
  8. Press the tab on the loop and draw out the loop into a tight circle (see Figure 5).
    Figure 5: Connecting the AC Power Supply Cord to an AC-Powered SwitchConnecting the AC Power Supply Cord to an AC-Powered Switch
  9. Dress the power cord appropriately. Verify that the power cords do not block access to switch components or drape where people can trip on them.
  10. Insert the power cord plug into the power source outlet.
  11. Connect the console port on the switch (labeled CON) to the external management device.
  12. Turn on power to the external management device.
  13. Switch on the dedicated customer-site circuit breakers for the power supply. Follow the instructions for your site.
  14. If the AC power source outlet has a power switch, set it to the on position.
    Note:

    After powering off a power supply, wait at least five seconds before turning it back on. After powering on a power supply, wait at least five seconds before turning it off.

    If the switch is completely powered off when you power on the power supply, the Routing Engine boots as the power supply completes its startup sequence. If the Routing Engine finishes booting and you need to power off the system again, first issue the CLI request vmhost power-off command. After a power supply is powered on, it can take up to five seconds for status indicators—such as the LEDs on the power supply and the show chassis command display—to indicate that the power supply is functioning normally. Ignore error indicators that appear during the first five seconds.

  15. If the power supply is installed correctly and functioning normally, the input status LED labeled AC and output status LED labeled DC on the power supply faceplate are on and steadily lit green, and the alarm LED (labeled !) is not lit.
  16. On the external management device, monitor the startup process to verify that the switch has booted properly.

Connecting DC Power to an EX9251 Switch and Powering on the Switch

Before you begin connecting DC power to an EX9251 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.

    CAUTION:

    To meet safety and electromagnetic interference (EMI) requirements and to ensure proper operation, you must connect EX9251 switches to earth ground before you connect them 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 earth ground. For instructions on connecting an EX9251 switch to ground using a separate grounding conductor, see Connect Earth Ground to an EX Series Switch.

  • Install DC power supplies in the chassis. See Installing a DC Power Supply in an EX9251 Switch.

Ensure that you have the following parts and tools available to connect DC power to an EX9251 switch:

  • An ESD wrist strap

  • DC power source cables (minimum 12 AWG (2.5 mm²), minimum 60°C wire or as permitted by local code)

  • Two ring lugs (Molex 01907000969 or equivalent)—provided with the switch

  • An external management device

  • Phillips (+) screwdriver, number 2

  • A multimeter

You can install up to two DC power supplies in an EX9251 switch. The DC power supply in an EX9251 switch is a hot-removable and hot-insertable field-replaceable unit (FRU). You can remove and replace it while the switch is running without turning off power to the switch or disrupting switching functions. The power supplies install in the slots on the rear panel of the chassis.

CAUTION:

Do not mix AC and DC power supplies in the same chassis.

Warning:

Before performing DC power procedures, ensure that power is removed from the DC circuit. To ensure that all power is off, locate the circuit breaker on the panel board that services the DC circuit, switch the circuit breaker to the off position, and tape the switch handle of the circuit breaker in the off position.

CAUTION:

Before you connect power to the switch, a licensed electrician must attach cable lugs 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).

Note:

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

To connect DC power to an EX9251 switch (see Figure 6):

  1. Switch off the dedicated customer site circuit breakers. Ensure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cable leads might become active during installation.
  2. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
  3. Remove the plastic cover from the terminal block on the power supply faceplate.
  4. Verify that the DC power cables are correctly labeled before making connections to the power supply. In a typical power distribution scheme where the return is connected to chassis ground at the battery plant, you can use a multimeter to verify the resistance of the –48V and RTN DC cables to chassis ground:
    • The cable with very large resistance (indicating an open circuit) to chassis ground is –48V.

    • The cable with very low resistance (indicating a closed circuit) to chassis ground is RTN.

    CAUTION:

    Ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on each power supply.

  5. Remove the screws from the terminals. Save the screws.
    CAUTION:

    Ensure that each power cable lug seats flush against the surface of the terminal block as you tighten the screws. Ensure that each screw is properly threaded into the terminal block. Before tightening each screw that you insert into the terminal block, ensure that you are able to spin the screw freely with your fingers. Applying installation torque to the screw when improperly threaded might damage the terminal block.

    The maximum torque rating of the terminal block on the DC power supply is 6 lb-in. (0.7 Nm). Excessive torque can damage the terminal block. Use only a Phillips (+) number 2 screwdriver to tighten screws on the DC power supply terminal block.

  6. Secure each power cable lug to the terminal block by using the screws and a Phillips (+) number 2 screwdriver. Do not overtighten the screws. Apply between 5 lb-in. (0.6 Nm) and 6 lb-in. (0.7 Nm) of torque to each screw (see Figure 6).

    When connecting DC power, the proper wiring sequence is ground to ground, then +RTN to +RTN, and finally –48 V to –48 V.

    Figure 6: Connect Power to a DC-Powered SwitchConnect Power to a DC-Powered Switch
    1. Secure the positive (+) DC source power cable lug to the return terminal (labeled V+).

    2. Secure the negative (–) DC source power cable lug to the –48V terminal (labeled V–).

  7. Replace the clear plastic cover over the terminal block.
  8. Verify that the power cables are connected correctly, that they do not touch or block access to switch components, and that they do not drape where people could trip on them.
  9. Connect the console port on the switch (labeled CON) to the external management device.
  10. Turn on power to the external management device.
  11. If the DC power source outlet has a power switch, set it to the on position.
    Note:

    After powering off a power supply, wait at least five seconds before turning it back on. After powering on a power supply, wait at least five seconds before turning it off.

    If the switch is completely powered off when you power on the power supply, the Routing Engine boots as the power supply completes its startup sequence. If the Routing Engine finishes booting and you need to power off the system again, first issue the CLI request vmhost power-off command. After a power supply is powered on, it can take up to five seconds for status indicators—such as the LEDs on the power supply and the show chassis command display—to indicate that the power supply is functioning normally. Ignore error indicators that appear during the first five seconds.

  12. If the power supply is installed correctly and functioning normally, the input status LED labeled IN and output status LED labeled OUT on the power supply faceplate are on and steadily lit green, and the alarm LED (labeled !) is not lit.
  13. On the external management device, monitor the startup process to verify that the switch has booted properly.