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Connecting the EX9253 to Power

Connecting Earth Ground to an EX9253 Switch

Before you begin to connect earth ground, ensure that you have the following parts and tools available:

  • A grounding cable (minimum 14– 10  AWG (2– 5.3  mm² ), minimum 60° C wire or as permitted by local code)— not provided

  • Two M5  Pan  Head screws to secure the grounding lug— provided in the accessory box shipped with the switch

  • A 14  AWG ground terminal lug sized for #10 screw (Panduit LCD10-14B-L or equivalent)— provided

  • A Phillips  (+) screwdrivers, numbers 2 (not provided)

  • An electrostatic discharge (ESD) grounding wrist strap

To ensure proper operation and to meet safety and electromagnetic interference (EMI) requirements, you must connect an EX9253 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 1).

You must install the EX9253 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. 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.

To connect earth ground to a switch:

CAUTION:

A licensed electrician must attach the grounding lug to the grounding cable.

  1. Wrap and fasten one end of an 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 all grounding surfaces are clean and brought to a bright finish before grounding connections are made.
  3. Connect the grounding cable to a proper earth ground.
  4. Detach the ESD grounding strap from the ESD point on the switch.
  5. Place the grounding cable lug over the grounding point on the side of the chassis (see Figure 1).
    Figure 1: Grounding Point on an EX9253 SwitchGrounding Point on an EX9253 Switch
      1

    Grounding point

     
  6. Secure the grounding lug on the grounding cable to the protective earthing terminal on the switch by using the screws (see Figure 2).
    Figure 2: Connecting a Grounding Cable to an EX9253 SwitchConnecting a Grounding Cable to an EX9253 Switch
  7. Connect the other end of the grounding cable to a proper earth ground.
  8. Dress the grounding cable appropriately. Ensure that it does not touch the switch components, block the air exhaust and access to the switch components, or drape where people could trip on it.

Connecting AC Power to an EX9253 Switch and Powering on the Switch

Before you begin to connect AC power and power on the switch, ensure that you have the following parts and tools available:

  • An AC power cord with a plug appropriate for your geographical location— provided

  • A power cord retainer— provided

  • An electrostatic discharge (ESD) grounding wrist strap— not provided

  • An external management device— not provided

Warning:

Ensure that you understand how to prevent ESD damage (see Prevention of Electrostatic Discharge Damage).

Depending on the model, you can use either AC or DC power supplies. The power supplies are hot-removable and hot-insertable field-replaceable units installed in the rear panel of the switch. You can replace them without powering off the switch or disrupting switch functions.

CAUTION:

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

Note:

An AC-powered switch gets additional grounding when you connect the power supply in the switch to a grounded AC power source outlet by using the power cord.

To connect power to an AC-powered switch (for each power supply):

  1. Locate the power cord that has a plug appropriate for your geographic location (see EX9253 Power System).
  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. Insert the coupler end of the power cord into the AC power cord inlet on the power supply.
  4. Push the power cord into the slot in the adjustment nut of the power cord retainer clip. Turn the nut until it is tight against the base of the coupler (see Figure 3).
    Figure 3: Connecting Power to an AC-Powered SwitchConnecting Power to an AC-Powered Switch
  5. If the AC power source outlet has a power switch, set it to the off position.
    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 either 15 A (110 VAC) minimum or 10  A (220 VAC) minimum, or as required by local code.

  6. Insert the power cord plug into the power source outlet.
  7. Dress the power cord appropriately. Ensure that it does not touch the switch components, block the air exhaust and access to switch components, or drape where people could trip on it.
    Note:

    After powering off a power supply, wait at least 60  seconds before turning it back on. After powering on a power supply, wait at least 60  seconds before turning it off.

    If the system 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  system  halt command.

    After a power supply is powered on, it can take up to 60  seconds for status indicators— such as the status LED 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 60  seconds.

  8. Connect an external management device to the port labeled CON on one of the Routing Engines.
  9. Turn on power to the external management device.
  10. Switch on the dedicated customer-site circuit breaker for the power supplies.
  11. If the AC power source outlet has a power switch, set it to the on position.
  12. Verify that the status LED on the power supply faceplate is on and steadily lit green.
  13. On the external management device, monitor the startup process to verify that the switch has booted properly.

Connecting DC Power to an EX9253 Switch and Powering on the Switch

Before you begin to connect DC power and power on the switch, ensure that you have the following parts and tools available:

  • Two DC power source cables (minimum 10  AWG (1.3  mm² ), minimum 60° C wire or as permitted by local code)—not provided

  • Two 16-14  AWG ring lugs sized for #6 screws (Panduit PN10-10R or equivalent)—provided

  • A torque-controlled socket nut driver, with a maximum torque capacity of 6  lb-in. (0.68 Nm), for tightening the screws on the terminals on each power supply—not provided

  • A wire cutter

  • An electrostatic discharge (ESD) grounding wrist strap—provided

  • An external management device—not provided

Warning:

Ensure that you understand how to prevent ESD damage (see Prevention of Electrostatic Discharge Damage).

Depending on the model, you can use either AC or DC power supplies. The power supplies are hot-removable and hot-insertable field-replaceable units installed in the rear panel of the switch. You can replace them without powering off the switch or disrupting switch functions.

CAUTION:

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

Note:

Grounding is required for models that use DC power supplies.

You connect DC power to the switch by attaching power cables from the DC power source to the terminals on the power supply faceplate.

CAUTION:

A licensed electrician must attach the ring lugs to the DC power cables.

Warning:

Before connecting the switch to a DC power source, ensure that the cable leads will not become active while you are connecting DC power and that the voltage across the DC power source cable leads is 0 V. Locate the input circuit breaker on the panel board that provides DC power, set the circuit breaker to the off position, and tape the switch handle of the circuit breaker in the off position. We recommend that you use a dedicated customer-site circuit breaker rated for 40 A (–48 VDC) minimum, or as required by local code. If you plan to operate a DC-powered switch at less than the maximum configuration and do not provision a 40  A  (– 48  VDC) circuit breaker, we recommend that you provision a dedicated customer-site circuit breaker for each DC power supply rated for at least 125 percent of the continuous current that the system draws at – 48  VDC.

Before you connect power to the switch, 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.

To connect power to a DC-powered switch (for each power supply):

  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 the cable leads do not become active during installation.
  2. 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:

    You must ensure that power connections maintain 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.

  3. Remove the nuts from the terminals. Save the nuts.
    CAUTION:

    Ensure that each power cable lug seats flush against the surface of the terminal block as you are tightening the nuts. Ensure that each nut is properly threaded into the terminal. Applying installation torque to the nuts when improperly threaded can result in damage to the terminal.

    CAUTION:

    The maximum torque rating of the terminal screws on the DC power supply is 6  lb-in. (0.68 Nm). The terminal screws might be damaged if excessive torque is applied. Use only a torque-controlled driver to tighten screws on the DC power supply terminals. Use an appropriately sized driver, with a maximum torque capacity of 6  lb-in. (0.68 Nm) or less. Ensure that the driver is undamaged and properly calibrated and that you have been trained in its use. You may want to use a driver that is designed to prevent overtorque when the preset torque level is achieved.

  4. Secure each power cable lug to the terminal with the nuts by using a socket nut driver (see Figure 4). Do not overtighten the nuts. Apply between 5 lb-in. (0.6 Nm) and 6  lb-in. (0.68 Nm) of torque to the nuts.
    1. Secure the positive (+) DC source power cable lug to the return terminal (labeled RTN).

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

    Figure 4: Connecting Power to a DC-Powered SwitchConnecting Power to a DC-Powered Switch
  5. Verify that the power cabling is correct. Ensure that cables do not touch the switch components, block the air exhaust and access to switch components, or drape where people could trip on them.
  6. Connect each DC power cable to the appropriate external DC power source.
  7. Dress the power cord appropriately. Ensure that it does not touch the switch components, block the air exhaust and access to switch components, or drape where people could trip on it.
    Note:

    After powering off a power supply, wait at least 60  seconds before turning it back on. After powering on a power supply, wait at least 60  seconds before turning it off.

    If the system 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  system  halt command.

    After a power supply is powered on, it can take up to 60  seconds for status indicators— such as the status 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 60  seconds.

  8. Connect an external management device to the port labeled CON on one of the Routing Engines.
  9. Turn on power to the external management device.
  10. Switch on the dedicated customer-site circuit breakers.
  11. Verify that the status LED on the power supply faceplate is on and steadily lit green. If the LED is not lit green:
    • Verify that the fuse is installed correctly, and turn on the breaker at the battery distribution fuse board or fuse bay.

    • Check the voltage with a meter at the terminals of the power supply for correct voltage level and polarity.

  12. On the external management device, monitor the startup process to verify that the switch has booted properly.