Grounding the DSC 8000

Grounding the DSC Platform hardware can vary depending on the site and national and/or local safety codes and practices.

The copper grounding bar is installed in the rear of the cabinet, left-side (approximately 77 x 1 x 0.25 inches). This grounding bar has 48 1/4-20 tapped holes for grounding connections from the PDU and the shelves.

The required hardware for the various connections is not supplied with the DSC Platform, but recommendations for this hardware are made for the in the following sections.

Before making any connections to the DSC Platform, the cabinet must be grounded as follows:

• To protect the platform from electrostatic discharge (ESD), and therefore to reduce the risk of damage to the equipment, the platform should be installed in an ESD protected environment (see Electrostatic Discharge Requirements).
• Always wear an antistatic wrist strap when installing or upgrading the platform. This wrist strap should be plugged into an ESD ground jack located at the rear or at the front of a shelf (see Electrostatic Discharge Requirements).
  The building installation must provide a means for connection to protective earth. The platform must be connected to this protective earth.Your service/maintenance person must arrange for the installation of protective earthing conductors.
• To reduce the possibility of electric shock from a telephone or Ethernet system, make all connections to the system grounding and power source before making these connects.
• Disconnect telephone and Ethernet before disconnecting your enclosure from the power source.

Connecting the Cabinet Grounding Bar to Facility Ground

The cabinet grounding bar must be connected to the floor grounding bus or Main Facility grounding bus, depending on the facility grounding design, and test result performed by the installation technicians. #2 AWG cables are recommended to compensate for longer cable runs, and higher resistance. It is also recommended that various sizes of lugs, bolts, nuts, star and regular copper washers are available at the time of the installation to adopt the grounding bar for proper grounding as required.

Grounding the PDU

The following table provides a summary of the recommended Power Distribution Unit (PDU) grounding connection hardware between the PDU and the grounding bar.

DSC 8000 PDU Grounding Hardware Summary (Example)

Unless otherwise indicated, the items listed in this table are not supplied with the DSC Platform.

The following figure illustrates the example PDU grounding connections.

Grounding Connection on the PDU (Example for one side)

The following figure illustrates an example of the PDU grounding connection to the grounding bar.

PDU Grounding Connection to the Grounding Bar (Example for one side)

Start

1. Make sure that the PDU is disconnected from any power source.
2. Using an appropriate wire cutting tool, cut one 8 AWG cable as required for the PDU ground to reach the grounding bar.
3. Remove approximately 12.7 mm (0.5 in.) of the insulation on both ends of the cable.

4. Insert each end of the cable into a 6.86 mm (1/4 in.) double main earthing lug such as an AMPOWER II, 4 AWG terminal, AMP P/N 606209 or equivalent, and using the appropriate crimping tool for this terminal, crimp the terminal onto the cable end.

   Tip

   The closest metric equivalent for a 1/4 in. ring terminal is a ring terminal for an M6 stud. This ring terminal has a 6.86 mm hole.

5. Remove the nut and lock washer from the PDU ground posts.
6. Place the cable’s double ring terminal on the ground posts.
7. Thread a nut and lock washer onto each ground post. The nuts and lock washers on the ground posts are 7/16 in. Use the appropriate torque wrench to securely fasten these nuts and lock washers onto the DC ground posts using 5.0Nm (45 lbf-in) torque.
8. Line up the other end of the cable’s double ring terminal with two holes on the grounding bar.
9. Fasten the double ring terminal with 1/4-20 x 1/2 Hex Serr Flange screws to the grounding bar.

Grounding the Shelves

Each shelf of the DSC Platform platform must be independently grounded to the grounding bar.

The following table provides a summary of example grounding hardware for each shelf. Unless otherwise indicated, the items listed in this table are not supplied with your hardware.

Shelf Grounding Hardware Summary (Example)

The following figure a shows the location of the shelf grounding posts.

Shelf Grounding Post

If the DSC Platform DC grounding post terminals are connected to the supply circuit ground, all of the following conditions must be met to comply with Underwriter Laboratories (UL) requirements:

• The chassis ground circuit must be directly connected to the DC supply circuit earthing conductor.
• If there is any other equipment connected to the ground of the same DC supply circuit, this equipment must be located in the same immediate area as the DC chassis (such as in adjacent racks).
• The grounding point of the DC chassis must also be located in the same immediate area.
• The DC supply source must be located within the same premise as the equipment it supplies.
• In the DC supply circuit, there must be no switches or disconnecting devices between the DC supply source and the circuit earthed ground.
• Attach a safety grounding cable to the grounding terminal on the chassis.

For additional grounding requirements, see Grounding Requirements.

Start

1. Depending on your build option, the shelf ground wire may already be installed. If so, go to step 6.
2. Using an appropriate wire cutting tool, cut one 8 AWG cable no longer than 4.6m (15ft.) for the chassis ground.
3. Remove approximately 12.7mm (½ in.) of the insulation on both ends of the 8 AWG cable.
4. Insert one of the stripped ends of the cable into the PANDUIT LCD8-14A-L double-hole, or equivalent, ring terminal. Using the appropriate size crimping tool for this terminal, crimp the terminal and the cable.
5. Remove the 8mm (5/16 in.) nuts and lock washers from the grounding posts.

6. Fit the double-hole terminal that is now securely crimped to the 8 AWG cable to both grounding posts.

   
     

7. Thread a nut and lock washer onto each grounding post and tighten them down over the ring terminal. Use the appropriate torque wrench with 2.8-3.4Nm (25-30 lb-in.) to secure the nuts and bolts onto the grounding posts.
   
   
8. Securely attach the other end of the grounding cable to an appropriate grounding point such as a grounding strip or grounded terminal rack. This connection depends on installation location; hence it is at the discretion of the installer. Make sure to install the DSC Platform chassis ground with metal screws and bolts that provide a good electrical connection between the installation hardware and the mounting surface. Failure to observe proper grounding practices may cause a safety issue.

Grounding the Cabinet Door

The following figure illustrates an example for grounding the cabinet door to the grounding bar. #8 AWG cable is recommended with #8 single or double hole lug and star washer. Heat shrink tube and heat gun are required for the installation.

Cabinet Door Grounding Connection

Grounding the Cabinet

The DSC Platform cabinet should be connected to the grounding bar similarly as the cabinet door (see preceding section).