Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

 

Connecting DC Power to an EX6200 Switch

 

An EX6200 switch can be configured with up to four DC power supplies. After you have installed at least one power supply, you can connect power to the switch.

Note

Grounding is required for DC systems and recommended for AC systems.

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 of power supplies (AC and DC) in the same chassis.

Before you begin connecting DC power to an EX6200 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 EX6200 switches to earth ground before you connect them to DC 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 EX6200 switch to ground using a separate grounding conductor, see Connecting Earth Ground to an EX Series Switch.

  • Install the power supply in the chassis. See Installing a DC Power Supply in an EX6200 Switch.

Ensure that you have the following parts and tools available to connect DC power to an EX6200 switch:

  • Electrostatic discharge (ESD) grounding strap

  • DC power source cables (not provided) with the cable lugs (provided) attached.

    The DC power source cables that you provide must be the same gage as the power source cables and as permitted by the local codes. We recommend that you install heat-shrink tubing insulation around the power cables and lugs.

  • 3/8 in. (9.5 mm) nut driver or socket wrench

  • Phillips (+) screwdriver, number 2

  • Multimeter

To connect DC power to an EX6200 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. Flip the Enable switch on the power supply faceplate to the Standby position.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 EX6200 Switch.

  3. Remove the plastic cover from the DC power input terminals, using the Phillips (+) screwdriver to loosen the screw (see Figure 1).
    Figure 1: Plastic Cover for Terminal Block
    Plastic Cover for Terminal
Block
  4. Remove the washers and nuts from each DC power input terminal, using the 3/8-in. (9.5 mm) nut driver or socket wrench to loosen the nuts. Leave the bolts installed on the input terminals.
  5. 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.
  6. 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 the multimeter to verify the resistance of the and + DC cables to chassis ground:
    • The cable with very high resistance (indicating an open circuit) to chassis ground is negative (–) and must be installed on the (input) DC power input terminal.

    • The cable with very low resistance (indicating a closed circuit) to chassis ground is positive (+) and must be installed on the + (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 50 A at –48 VDC.

    Note

    A 2100 W DC power supply requires a dedicated 60 A circuit breaker for each input DC feed.

    Note

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

  7. Install each power cable lug on the DC power input terminal, securing it first with a locking washer, then with the nut (see Figure 2). Caution

    Apply maximum of 56.4 in.-lb (6.4 Nm) of torque to tighten each nut—do not overtighten. Applying excessive force might damage the terminal studs or power supply.

    1. Secure each positive (+) DC source power cable lug to the + (return) DC power input terminal.

    2. Secure each negative (–) DC source power cable lug to the (input) DC power input terminal.

    Note

    If the optional power cord tray is installed, you can thread the DC power cables through the power cord tray.

    Figure 2: Connecting the Power Supply Cables to an EX6200 Switch
  8. Install the plastic cover over the DC input terminals, using the Phillips (+) screwdriver to tighten the screw (see Figure 1).Caution

    Do not overtighten the screws. Applying excessive force might damage the screws or power supply.

  9. Ensure that the power supply is fully inserted and secured in the chassis. See Installing a DC Power Supply in an EX6200 Switch.
  10. Repeat Steps 2 through 9 for the remaining power supplies.