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Connecting the EX4500 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 Rack
Connecting 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 Switch
    Connecting 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 EX4500 Switch

The AC power supply in an EX4500 switch is a hot-removable and hot-insertable field-replaceable unit (FRU). After you have installed at least one power supply, you can connect power to the switch.

Caution

Operating the switch with an incorrect power supply might cause the chassis to overheat. See Installing an AC Power Supply in an EX4500 Switch.

Ensure that you have connected the device chassis to earth ground, if required by your site guidelines or installation. A ground connection to the protective earthing terminal is not required for an AC-powered switch. The AC power cords provide adequate grounding when you connect the power supply in the switch to a grounded AC power outlet by using the AC power cord appropriate for your geographical location (see AC Power Cord Specifications for an EX4500 Switch).

Caution

For installations that require a separate grounding conductor to the chassis, have a licensed electrician complete this connection before you connect the switch to power. For instructions on connecting earth ground, see Connect Earth Ground to an EX Series Switch.

Note

Each power supply must be connected to a dedicated AC power source outlet.

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:

Warning

Ensure that the power cords do not block access to switch components or drape where people can trip on them.

To connect AC power to the switch:

  1. Attach the electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to the ESD point on the chassis.
  2. Ensure that the power supply is fully inserted in the chassis. See Installing an AC Power Supply in an EX4500 Switch.
  3. Squeeze the two sides of the power cord retainer clip, and insert the L-shaped ends of the clip into the holes in the bracket on each side of the AC appliance inlet. See Figure 3.
    Figure 3: Power Cord Retainer in an AC Power Supply
    Power Cord Retainer in an
AC Power Supply
  4. Locate the power cord or cords shipped with the switch; the cords have plugs appropriate for your geographical location.
  5. Insert the coupler end of the power cord into the AC appliance inlet.
  6. Push the retainer clip toward the cord until the cord slides into the slot in the adjustment nut. Turn the nut until it is tight against the base of the coupler and the slot in the nut is turned 90° from the top of the switch. See Figure 4.
  7. If the AC power source outlet has a power switch, set it to the OFF (0) position.
  8. Insert the power cord plug into an AC power source outlet.
  9. If the AC power source outlet has a power switch, set it to the ON (|) position.
  10. Verify that the LED on the power supply faceplate is lit and is on steadily.
  11. Repeat steps 2 through 10 for the remaining power supplies.
Figure 4: Connecting the Power Supply Cord to an EX4500 Switch
Connecting the Power
Supply Cord to an EX4500 Switch

Connecting DC Power to an EX4500 Switch

You can install two DC power supplies in an EX4500 switch. After you have installed at least one power supply, you can connect power to the switch.

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 a cable lug 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).

Caution

Do not mix different types (AC and DC) of power supplies or power supplies with front-to-back or back-to-front airflow in the same chassis.

Before you begin connecting DC power to the switch:

  • Ensure that you have taken the necessary precautions to prevent 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 EX4500 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 EX4500 switch to ground using a separate grounding conductor, see Connect Earth Ground to an EX Series Switch.

  • Install the power supply in the chassis. See Installing a DC Power Supply in an EX4500 Switch.

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

  • Electrostatic discharge (ESD) grounding strap

  • DC power source cables (not provided) with the cable lugs (Molex 190410014 or equivalent) (not provided) attached

  • Phillips (+) screwdriver, number 2

  • Multimeter

To connect DC power to the switch:

  1. Attach the electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to the ESD point on the chassis.
  2. Remove the plastic cover from the DC power input terminal block by sliding it off either to the left or right. Save this cover for future use. See Figure 5. Note

    It might be necessary to slide each power supply partially out of the chassis to easily connect the DC power source cables to the DC power input terminals. See Removing a DC Power Supply from an EX4500 Switch.

    Figure 5: Remove Plastic Cover from Terminal Block
    Remove Plastic
Cover from Terminal Block
  3. Remove the locking screws from each DC power input terminal, using the screwdriver.
  4. Ensure that the power source circuit breaker is open so that the voltage across the DC power source cable leads is 0 V and that the cable leads do not become active while you are connecting DC power.
  5. 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 high resistance (indicating an open circuit) to chassis ground is negative (–) and will be installed on the –48V (input) DC power input terminal.

    • The cable with very low resistance (indicating a closed circuit) to chassis ground is positive (+) and will be installed on the RTN (return) DC power input terminal.

    Caution

    You must 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 DC power input terminals on each power supply.

    Warning

    Ensure that the power cables do not block access to switch components or drape where people can trip on them.

    Note

    To supply sufficient power, terminate the DC input wiring on a facility DC source that is capable of supplying a minimum of 20 A at –48 VDC.

    Note

    A 1200 W DC power supply requires a dedicated 30 A circuit breaker for each input DC feed.

    Note

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

  6. Install each power cable lug on the DC power input terminal, securing it with the locking screw, (see Figure 6). Apply between 9 in.-lb (1.1 Nm) and 12 in.-lb (1.3 Nm) of torque to tighten each locking screw.
    Figure 6: Connecting the Power Supply Cables to an EX4500 Switch
    Connecting the
Power Supply Cables to an EX4500 Switch
  7. Slide the plastic cover over the input terminal block. See Figure 7 .
    Figure 7: Install Plastic Cover on Terminal Block
    Install Plastic
Cover on Terminal Block
  8. Ensure that the power supply is fully inserted and latched securely in the chassis. See Installing a DC Power Supply in an EX4500 Switch.
  9. Repeat Steps 2 through 8 for any remaining power supply.