Transcript
APPLICATION NOTE
Ensuring Shielding Integrity to Ground in a Leviton Shielded Twisted Pair Installation by Dan Underbrink, RCDD, Principal Applications Engineer, Leviton Network Solutions
2. Run a Telecommunications Equipment Bonding Conductor (TEBC) for each row of racks or cabinets from the SBB.
TR
TBB (telecommunications bonding backbone)
TEBC (telecommunications equipment bonding conductor)
SBB (secondary bonding bussbar)
The following recommendations are best practices for ensuring shield integrity to ground for any Leviton shielded installation. The points below highlight grounding and bonding elements within a single telecommunications room. The ANSI/TIA-607-C standard outlines additional elements required for a larger Telecommunications Grounding System. 1. Install the Telecommunications Grounding System per TIA-607-C. • Use a Secondary Bonding Bussbar (SBB), formerly known as a Telecommunications Grounding Bussbar or TGB, within the Telecommunications Room/Horizontal Cross-connect (TR/HC) • The SBB should be bonded to the Primary Bonding Bussbar (PBB), formerly Telecommunications Main Grounding Bussbar or TMGB). This bonding element is called the Telecommunications Bonding Backbone (TBB). • Connections of SBB to the PBB should be made with an appropriate-size, UL listed, two-hole crimp style lug and appropriate gauge cable. • The PBB should be bonded via Telecommunications Bonding Conductor (TBC) to Structural Steel/Building Ground. If a bond to structural steel cannot be obtained, use the electrical system ground point. • Use recommendations from the TIA-607-C standard for proper conductor gauge for all of the above TBB and TBC connections.
• This is typically a #6 AWG bare or green-insulated stranded copper wire. • If insulated, the insulation must be appropriate for the space through which the TEBC runs (e.g., use plenum CMP insulation if running through a plenum space). • Connections of TEBC to the SBB should be made with an appropriate-size, UL listed, two-hole crimp style lug. 3. Ensure a specific equipment grounding element for each rack or cabinet. • Equipment connections to each rack or cabinet from the TEBC may use any one of the following three methods: • A Horizontal Rack Bonding Bussbar (Horizontal RBB) mounted to the rack or cabinet vertical equipment mounting rails. • A Vertical Rack Bonding Bussbar (Vertical RBB) mounted to and running the full height of the rack or cabinet. • A #6 AWG Rack Bonding Conductor (RBC) running full height of the rack or cabinet • For each of the three rack/cabinet options above, connections are made to the TEBC via irreversible compression-type connections. • The rack or cabinet itself is independently bonded to the TEBC via irreversible compressiontype connection. This ensures the structural metal of the rack or cabinet is bonded to the Telecommunications Grounding System in case that metal should become inadvertently energized. • Note: the grounding/bonding parts mentioned above are not provided by Leviton. Each of the elements above should be installed and tested per manufacturer recommendations to ensure a low-impedance path to ground.
Leviton Network Solutions 2222 - 222nd St. SE Bothell, WA 98021 Tech Support: 800.824.3005 +1.425.486.2222 Fax: 1.425.485.9170 www.leviton.com © 2017 Leviton Manufacturing, Inc All rights reserved. Subject to change without notice.
APPLICATION NOTE
• A Leviton shielded patch panel must be used. Various standard and high-density options are available, as well as flat and angled shielded options. • All patch cords used must be shielded patch cords. • Leviton Shielded Patch Panels are engineered to provide a low impedance path from the shielded connector bodies (i.e. shielded jacks) to the Patch Panel sheet metal. • A grounding stud is provided on the standard-density shielded patch panels. • For high-density shielded patch panels, the ground stud is accomplished via installation of a long rack-mount screw provided with the panel. Follow specific instructions that are included with these panels to ensure that adequate grounding is accomplished as part of panel installation. • If the permanent link or channel architecture includes a consolidation point (CP): • Shield continuity must be maintained across the CP interconnect. • Leviton recommends a shielded patch panel in the CP for interconnect purposes. Standards do not allow cross-connects in a CP. • Grounding for this architecture is still performed at the TR shielded patch panel (i.e. no shield grounding performed at/within the CP). • Horizontal cable section A will be a shielded cable running from the TR shielded patch panel to the rear of jack in the CP shielded patch panel. • Horizontal cable section B will be a shielded plug-to-jack cable assembly running from the front of the CP panel (shielded plug end into CP shielded jack in the patch panel and shielded jack end into workstation outlet). • Alternately, horizontal cable section B may be a plug-to-open cable assembly (shielded plug end into CP shielded jack in the patch panel and open end cut to length and field terminated to a shielded jack for the workstation outlet). • Shielded plug-to-jack or plug-to-open cable assemblies are make-to-order products available from Leviton.
5. The field tester should be set for the appropriate category rating for the wiring system (i.e. Cat 5e, Cat 6, or Cat 6A) and for FTP cable type. • Field tester shield continuity testing should be enabled. • All permanent links or channels should be characterized with the field tester, including shield integrity test. Repairs of any problem links should be undertaken and completed. 6. Finally, an individual equipment Unit Bonding Conductor (UBC) should be installed from each shielded patch panel to whatever element was provided for rack or cabinet bonding (i.e. Horizontal RBB, Vertical RBB, or RBC). This ensures bond integrity of the shielded links or Channels to the Telecommunications Grounding System. • If RBC was chosen as the rack or cabinet bonding element, UBC connections to the RBC are accomplished via irreversible compression type connector. • UBC connections to RBBs should be made with UL listed two-hole lugs. • Best practice would be for each shielded patch panel UBC to be a #6 AWG wire (NEC and TIA-607-C require a minimum #12 AWG for the UBC). • The thought behind the #6 AWG UBC as best practice is that this element is bonding the shields of all links or channels in the shielded patch panel (i.e. 24 or 48 Links or Channels). • If most or all of these shields were to become inadvertently energized, one would want a UBC of sufficient size to reliably shunt this undesirable energy to ground. In summary: • Install and verify the Telecommunications Grounding System (TBC, PBB, TBB, SBB, TEBC, and RBB or RBC) Per ANSI/TIA-607-C. • Install and verify all Leviton shielded permanent links or channels. • Install individual #6 AWG equipment Unit Bonding Conductors (UBC) between each shielded patch panel and the rack or cabinet bonding element. • Shielded permanent links or channels are bonded to the Telecommunications Grounding System at one point (the shielded patch panel). No grounding is done at the work area connector (which is typically a jack in a wallplate). Learn more about Leviton shielded solutions at Leviton.com/Copper.
Leviton Network Solutions 2222 - 222nd St. SE Bothell, WA 98021 Tech Support: 800.824.3005 +1.425.486.2222 Fax: 1.425.485.9170 www.leviton.com © 2017 Leviton Manufacturing, Inc All rights reserved. Subject to change without notice.
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4. Install Leviton shielded permanent link (work area jack to patch panel) or channel (includes patch cords at both ends) per the Leviton Shielded Connector Instruction Sheet.
