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Replacing an MX2020 Three-Phase Delta AC Power Cord

The MX2020 router has either one redundant PDM or two redundant PDMs. An AC power cord on a redundant PDM is hot-insertable and hot-removable. When a redundant PDM is powered down, the other PDM automatically assumes the entire electrical load for the router. If you have only one PDM, you must power off the system before removing the AC power cord.

Removing an MX2020 Three-Phase Delta AC Power Cord

To remove a three-phase delta AC power cord:

  1. Switch off the customer site circuit breakers to the PDM being removed. Make sure that the voltage across the AC power source cord is 0 V and that there is no chance that the cord might become active during the installation process.
  2. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
  3. Switch the power switch on the PSM faceplate to the off (O) position.
    Note:

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

  4. Remove the ESD grounding strap from the ESD point on the chassis, and attach it to an approved site ESD grounding point. See the instructions for your site.
  5. Disconnect the AC power cord (see Figure 1) from the power source.
    Figure 1: Three-Phase Delta AC Power CordThree-Phase Delta AC Power Cord
  6. Remove the ESD grounding strap from the approved site ESD grounding point. See the instructions for your site. Reconnect the strap to one of the ESD points on the chassis.
  7. Using a number 2 Phillips (+) screwdriver, loosen the four screws on the cover of the metal wiring compartment that protects the AC terminal block.
  8. Remove the cover of the metal wiring compartment.
  9. Disconnect the wires from the AC terminal block on the three-phase delta AC PDM (see Figure 2). Loosen each of the input terminals or grounding point screws, and remove each wire from the grounding point or input terminal.
    Note:

    The terminal connections have either slotted screws or hex screws. Use a 1/4-in. slotted screwdriver for the slotted screws. Use a 5/32-in. (4 mm) Allen wrench for the 5/16-in. hex screws.

    To remove wires from the terminal block that serves six PSMs:

    1. Remove the wire labeled L3 from the input terminal labeled C1.

    2. Remove the wire labeled L2 from the input terminal labeled B1.

    3. Remove the wire labeled L1 from the input terminal labeled A1.

    4. Remove the grounding wire from the grounding point labeled GND.

    Figure 2: Disconnecting the Power Cord from a Three-Phase Delta AC Power Distribution ModuleDisconnecting the Power Cord from a Three-Phase Delta AC Power Distribution Module

    To remove wires from the terminal block that serves three PSMs:

    1. Remove the wire labeled L3 from the input terminal labeled C2.

    2. Remove the wire labeled L2 from the input terminal labeled B2.

    3. Remove the wire labeled L1 from the input terminal labeled A2.

    4. Remove the grounding wire from the grounding point labeled GND.

    Note:

    The three-phase delta AC PDM terminal blocks will be flipped depending on which slot the PDM gets plugged into.

  10. Loosen the plastic cable tie fastening the AC power cord to the PDM.
  11. Loosen and remove the retaining nut from the AC power cord.
  12. Pull the AC power cord out of the metal wiring compartment.
  13. Carefully move the AC power cable out of the way.
  14. Disconnect the AC power cord from the AC PDM.

See Also

Installing an MX2020 Three-Phase Delta AC Power Cord

To install a three-phase delta AC power cord:

  1. Switch off the customer site circuit breakers to the PDM being removed. Make sure that the voltage across the AC power source cord is 0 V and that there is no chance that the cord might become active during the installation process.
  2. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
  3. Switch the power switches on all the PSM faceplates to the off (O) position for any PSMs that are powered only from this PDM.
    Note:

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

  4. Using a number 2 Phillips (+) screwdriver, loosen the four screws on the cover of the metal wiring compartment that protects the AC terminal block.
  5. Remove the cover of the metal AC wiring compartment.
  6. Unscrew the retaining nut from the AC power cord.
  7. Place the retaining nut inside the metal wiring compartment.
  8. Put the wires of the AC power cord through the hole of the retaining nut and rubber grommet.
  9. Put the wires of the AC power cord through the hole of the metal wiring compartment.
  10. Connect the wires to the AC terminal block on the three-phase delta AC PDM (see Figure 3). Loosen each of the input terminal or grounding point screws, and insert the wire into the grounding point or input terminal, and tighten the screw (see Table 1 for approved AC wire gauge).

    To insert wires into the terminal block that serves six PSMs:

    1. Insert the grounding wire into the grounding point labeled GND.

    2. Insert the wire labeled L1 into the input terminal labeled A1.

    3. Insert the wire labeled L2 into the input terminal labeled B1.

    4. Insert the wire labeled L3 into the input terminal labeled C1.

    Figure 3: Connecting Power to a Three-Phase Delta AC Power Distribution ModuleConnecting Power to a Three-Phase Delta AC Power Distribution Module
    Note:

    The three-phase delta AC PDM terminal blocks will be flipped depending on which slot the PDM gets plugged into.

    Note:

    The color of each AC power wire might vary. The MX2020 chassis is not sensitive to phase rotation sequence—either CW or CCW will operate correctly.

    CAUTION:

    Wire label configuration is for Juniper Networks supplied cable only. If using your own cable, make sure you use the proper connections.

    To insert wires into the terminal block that serves three PSMs:

    1. Insert the grounding wire into the grounding point labeled GND.

    2. Insert the wire labeled L1 into the input terminal labeled A2.

    3. Insert the wire labeled L2 into the input terminal labeled B2.

    4. Insert the wire labeled L3 into the input terminal labeled C2.

    Note:

    The terminal connections have either slotted screws or hex screws. Use a 1/4-in. slotted screwdriver for the slotted screws. Use a 5/32-in. (4 mm) Allen wrench for the 5/16-in. hex screws.

    Warning:

    To protect power supplies from input voltage that may be caused by miswired PDMs, before reinstalling the metal cover to the wiring compartment apply AC voltage to the PDM (with disengaged PSM) to make sure that two LEDs on the PDM are lit green and that the AC voltage between AC terminal blocks A1-B1, B1-C1, C1-A1, A2-B2, B2-C2, and C2-A2 for three-phase delta PDM is not more than 264VAC when measured with a DVM. Then turn off the AC breaker de-energizing the PDM and install the metal cover and engage all AC PSMs.

    Note:

    Three-phase delta AC wire assembly kits can be purchased from Juniper Networks.
    Table 1: Supported Three-Phase Delta AC Wire Gauge
    Wire Gauge Description

    4 x 6-AWG or equivalent

    4 conductor wires, each wire is 6-AWG
    Note:

    We recommend that you use the proper gauge wire in order for the cable clamps to hold the AC cables. Using smaller gauge wiring will result in the cable clamps not tightening properly.

    Warning:

    Power connections must be performed by a licensed electrician only.

  11. Verify that the power cord wire connections are correct.
  12. Screw the retaining nut onto the AC power cord to secure it to the metal wiring compartment.
  13. Using a number 2 Phillips (+) screwdriver, tighten the four captive screws on the metal AC wiring compartment.
  14. Verify that the AC power cord is not touching or blocking access to router components, and that it does not drape where people could trip on it.
  15. Remove the ESD grounding strap from the ESD points on the chassis. Connect the strap to an approved site ESD ground point. See the instructions for your site.
  16. Connect the AC power cord plug to the power source.
  17. Switch on the customer site circuit breakers to provide voltage to the AC power cord.
  18. Remove the ESD grounding strap from the approved site ESD grounding point. See the instructions for your site. Reconnect the strap to one of the ESD points on the chassis.
  19. Verify the LED on the PDM faceplate is lit steadily, indicating that the AC terminal block is receiving power.
  20. Switch the power switch on the PSM to the on (|) position to provide power to the router components.
    Note:

    After a PDM is powered on, it can take up to 60 seconds for status indicators—such as the LEDs on the PDM, the command output displays, and messages on the LED display on the craft interface—to indicate that the PDM is functioning normally. Ignore error indicators that appear during the first 60 seconds.

See Also

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