Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

Navigation
Guide That Contains This Content
[+] Expand All
[-] Collapse All

    Connecting AC Power to an MX2020 Router with Three-Phase Delta AC Power Distribution Modules

    Caution: Do not mix AC and DC power modules within the same router.

    Warning: Power connections must be performed by a licensed electrician only.

    You connect AC power to the router with three-phase delta AC PDMs by connecting the AC power cord from an AC PDM to an AC power source.

    To connect an AC power cord to an AC power source:

    1. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to an approved site ESD grounding point. See the instructions for your site.
    2. Switch off the dedicated customer site circuit breakers. Ensure that the voltage across the AC power source cable leads is 0 V and that there is no chance that the cable leads might become active during installation.
    3. Detach the ESD grounding strap from the approved site ESD grounding point, and connect the strap to one of the ESD points on the chassis.
    4. Switch the power switches on all the PSM faceplates to the off (O) position.
    5. Verify that the correct three-phase delta PDMs are installed and secured in the chassis before connecting power cables.

      Note: The power cables must be uninstalled and removed from the three-phase delta PDM before removal of the PDM from the chassis.

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

      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 connect wires to 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 1: Connecting Power to a Three-Phase Delta AC Power Distribution Module

      Connecting
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 connect wires to 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.

      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: 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.

      Note: Three-phase delta AC wire assembly kits can be purchased from Juniper Networks.

      Table 1: Supported Three-Phase Delta AC Wire Gauge

      Wire GaugeDescription

      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.

    12. Verify that the power cable connections are correct.
    13. Screw the retaining nut onto the AC power cord to secure it to the metal wiring compartment.
    14. Reinstall the metal PDM wiring cover, and using a number 2 Phillips (+) screwdriver, tighten the four captive screws on the metal AC wiring compartment. Apply between 10 lb-in. (1.13 Nm) to 12 lb-in. (1.35 Nm) of torque to each screw. Do not overtighten the screws.
    15. Use the provided plastic cable tie to fasten the AC power cord to the PDM.
    16. 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.
    17. Repeat the procedure for the other three-phase delta AC PDMs.

    Modified: 2016-03-29