Grounding the Power Supply and Connecting the DC Power Inputs

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 source circuit, switch the circuit breaker to the off position, and tape the switch handle of the circuit breaker in the off position.

Note: For redundant systems, we recommend that you use a dedicated power source for each power supply so that the system can remain operational if a power supply fails and must be replaced.

You ground the device by connecting a grounding cable to earth ground and then attaching it to the grounding point on the DC power supply. You must provide the grounding cables. The cable lug used on the grounding cable should have a #10 stud hole and accommodate a minimum of 12-AWG wire. We recommend using the PANDUIT® LCB8-10H-L lug, which accommodates 8-AWG wire. See Table 9 for the specifications of the grounding lug and cables.

You connect DC power to the power supply by attaching power cables from the external DC power source to the terminal block on the DC power supply. You must provide the power cables. You must use a minimum of 12-AWG wire for the power cables. See Table 8 for the specifications of the power cables.

To connect the ground and DC power source cables to the power supply:

  1. Ensure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cable leads might become active during installation.
  2. Ground the power supply:
    1. Loosen the ground connection on the power supply.
    2. Connect the grounding cable to a proper earth ground.
    3. Secure the grounding cable to the power supply grounding point.
  3. Connect the DC power source input to the power supply:
    1. Loosen the –48V (input) and RTN (return) screws on the power supply terminal block.
    2. Secure the positive (+) DC power source cable to the RTN (return) terminal on the power supply.
    3. Secure the negative (–) DC power source cable to the –48V (input) terminal on the power supply.

    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 terminal studs on each power supply.

  4. If you are installing multiple power supplies, repeat Steps 1–3 for each power supply in the chassis.
  5. Route and secure the power cables with plastic cable ties, which you must provide.
  6. Verify that the power cabling is correct, that the cables are not touching or blocking access to other chassis components, and that they do not drape where people could trip on them.
  7. Switch on the DC power source circuit breaker. Follow your site's procedures for safety and ESD.