Please enable the view of Javascript on your browser, so that you may view update information.
ACCC Home Page ACADEMIC COMPUTING and COMMUNICATIONS CENTER
Accounts / Passwords Email Labs / Classrooms Telecom Network Security Software Computing and Network Services Education / Teaching Getting Help
 
  1. GROUNDING AND BONDING


    1. All UIC Telecommunications Equipment and raceways shall be properly grounded in accordance with ANSI/TIA/EIA-607, the NFPA 70 (National Electrical Code), Chicago Electrical Code, and all other applicable codes and regulations.


    2. The major components of the telecommunications grounding and bonding infrastructure are as follows: (See diagram 8a).


      1. The bonding conductor for telecommunications.


      2. The Telecommunications Main Grounding Busbar (TMGB).


      3. The Telecommunications Grounding Busbar (TGB).


      4. The Telecommunications Bonding Backbone (TBB).


      5. The Telecommunications Bonding Backbone Interconnecting Bonding Conductor (TBBIBC).


      6. The conductors used to bond the components to the TMGB & the TGB's.


      Click for Diagram 8a
    3. The bonding conductor for telecommunications.


      1. The bonding conductor for telecommunications shall bond the TMGB to the service equipment (power) ground.


      2. This bonding conductor is intended to conduct lightning and ac fault currents from the telecommunication primary protectors.


      3. A minimum of 300 mm (1 ft) separation shall be maintained between this insulated conductor and any dc power cables, switchboard cable, or high frequency cables, even when isolated by metallic conduit or EMT.


      4. The minimum size for this conductor shall be 3/0 green insulated stranded copper cable.


    4. The Telecommunications Main Grounding Busbar (TMGB).


      1. The Telecommunications Main Grounding Busbar (TMGB) serves as the dedicated extension of the building grounding electrode system for the telecommunications infrastructure. The TMGB also serves as the central attachment point for telecommunications bonding backbones (TBB) and equipment, and is located such that it is accessible to telecommunications personnel.


      2. The IDF / Node is the desirable location for the TMGB. This TMGB may serve as the TGB for collocated equipment in the IDF / Node as appropriate.


      3. The TMGB should be located so that the bonding conductor for telecommunications is as short and straight as possible.


      4. The TMGB should be located to result in the straightest route considering the total length of the bonding conductor from the telecommunications primary protectors to the TMGB.


      5. The TMGB should be located near the backbone cabling and associated terminations.


      6. The TMGB shall be as close to the Data Racks as practicable and shall be installed to maintain clearances required by applicable electrical codes.


      7. Telecommunications primary protectors on the inter-building backbone cables shall be bonded to the TMGB.


      8. The TMGB is the common point in the IDF/Node to which all grounding connections for that room are made.


      9. The TMGB is intended to be the location for connecting grounding bars incorporated in telecommunications equipment located in the TEF (e.g., MUX or optical fiber termination equipment).


      10. The connections of the bonding conductor for telecommunications and the TBB's to the TMGB shall utilize listed 2-hole compression connectors, exothermic type welded connections, or equivalent.


      11. The TMGB shall be a predrilled copper busbar provided with standard NEMA bolt hole sizing and spacing for the type of connectors to be used.


      12. The TMGB shall have minimum dimensions of 1/4" thick x 4" wide and 12" in length. The length may need to be adjusted longer to meet the application requirements with consideration of future growth.


      13. It is required that the busbar be electrotin-plated for reduced contact resistance.


      14. The TMGB shall be insulated from its support. A 50 mm (2 in) separation is required.


      15. Where an electrical panelboard for telecommunications is located in the same room or space as the TMGB, that panelboard's Alternating Current Equipment Ground (ACEG) bus (when equipped) or the enclosure shall be bonded to the TMGB.


    5. The Telecommunications Grounding Busbar (TGB).


      1. The Telecommunications Grounding Busbar (TGB) is the common central point of connection for telecommunications systems and equipment in the location served by that telecommunications closet or equipment room.


      2. Each telecommunications closet and equipment room shall contain a TGB.


      3. The TGB should be located near the backbone cabling and associated terminations.


      4. The TGB should be located so that the grounding conductors are as short and straight as possible.


      5. The bonding conductor between a TBB and TGB shall be continuous and routed in the shortest possible straight-line path.


      6. The TGB shall be a predrilled copper busbar provided with standard NEMA bolt hole sizing and spacing for the type of connectors to be used.


      7. The TGB shall have minimum dimensions of 1/4" thick x 4" wide and 12" in length.


      8. It is required that the busbar be electrotin-plated for reduced contact resistance.


      9. The TGB shall be insulated from its support. A 50 mm (2 in) separation is required.


      10. Where an electrical panelboard for telecommunications is located in the same room or space as the TGB, that panelboard's Alternating Current Equipment Ground (ACEG) bus (when equipped) or the enclosure shall be bonded to the TGB.


      11. Where a panelboard for telecommunications is not located within the same room or space as the TGB, consideration should be given to bonding the panelboard's ACEG bus (when equipped) or the enclosure to the TGB.


      12. Bonding to the metal frame of a building


        1. All bonding conductors and connectors for bonding the metal frame of a building shall be listed for the purpose intended and approved by a NRTL.


        2. In buildings where metal frames (structural steel) are effectively grounded, each TGB shall be bonded to the metal frame within the room using a No. 6 AWG conductor.


        3. Where the metal frame is external to the room and readily accessible the metal frame should be bonded to the TGB with a No. 6 AWG conductor.


        4. Where the metal frame is external to the room and readily accessible the metal frame should be bonded to the TMGB with a No. 6 AWG conductor.


        5. When practicable because of shorter distances and other considerations, and where horizontal steel members are permanently electrically bonded to vertical column members, TGB's may be bonded to these horizontal members in lieu of the vertical column members.


        6. This Standard does not require the steel bars of a reinforced concrete building to be bonded to the TGB or TBB.


    6. The Telecommunications Bonding Backbone (TBB).


      1. A TBB is a conductor that interconnects all TGB's with the TMGB. A TBB's basic function is to reduce or equalize potential differences between telecommunications systems bonded to it. A TBB is not intended to serve as the only conductor providing a ground fault current return path.


      2. A TBB should be designed with consideration given to the type of building construction, building size, the telecommunications requirements, and the configuration of the telecommunications pathways and spaces. Specifically, the design of a TBB shall:


        1. be consistent with the design of the telecommunications backbone cabling system.


        2. permit multiple TBB as dictated by the building size.


        3. address routing to minimize the lengths of the TBB.


      3. A TBB shall be an insulated copper conductor. The minimum TBB conductor size shall be a No. 3/0 AWG.


      4. TBB conductors should be installed without splices, where practicable. Where splices are necessary they should be minimum and shall be accessible and located in telecommunications spaces. Joined segments of a TBB shall be connected using irreversible compression-type connectors, exothermic welding, or equivalent. All joints shall be adequately supported and protected from damage.


    7. The Telecommunications Bonding Backbone Interconnecting Bonding Conductor (TBBIBC).


      1. Whenever two or more vertical TBB are used within a multistory building, the TBB shall be bonded together with a TBB interconnecting bonding conductor (TBBIBC) at the top floor and at a minimum of every third floor in between.


      2. The TBBIBC shall be sized as 3/0 green insulated stranded copper cable.


    8. All bonding conductors and connectors shall be listed for the purpose intended and approved by a Nationally Recognized Testing Laboratory (NRTL).


    9. All bonding conductors shall have green insulation and be copper. The minimum bonding conductor size shall be a No. 6 AWG.


    10. Route ground conductors to provide the shortest, most direct path from point to point.


    11. Bonding conductors should not be placed in ferrous metallic conduit. If it is necessary to place bonding conductors in ferrous metallic conduit that exceeds 1 m (3 ft) in length, the conductors shall be bonded to each end of the conduit with a conductor sized as a No. 6 AWG, minimum (this makes the conduit a parallel path with the cable).


    12. Splices in bonding or grounding conductors are not allowed.


    13. A continuous ground path shall be provided in all telecommunications raceways.


    14. The IDF protector frames shall be grounded to the TMGB.


    15. At each FDF all equipment and raceways must be bonded to the TGB.


    16. Any grounding or bonding conductor which is run through a metallic conduit shall be bonded to the conduit at both ends.


    17. Gas pipes must not be utilized as a grounding electrode.


    18. Water pipes must not be used as a grounding electrode except for the service equipment power ground.


    19. The Telecommunications Ground & Bonding System shall be tested with a Earth Ground Resistance Tester used in the Two Point Test Method. (Diagram 8b)



    20. The following will be needed to test the grounding and bonding. They can be supplied by UIC ACCC TED.


      1. An Earth Ground Resistance Tester with the attachments.


      2. 500 foot reel of # 10 copper wire with ground clamps on both ends.


    21. The following is the procedure to test the grounding & bonding:


      1. All testing should be done with the entire building in operation. Nothing needs to be shut down to test the grounding and bonding with this tester.


      2. Set up the meter in the two point test mode.


      3. Zero the meter using the 500 foot number 10 copper test lead.


      4. Connect the short test lead from the meter to the close end of the wire/cable under test.


      5. Connect the end of the 500 foot lead to the other end of the wire/cable under test.


      6. Take the reading of the wire/cable under test.


      7. If the ohmic value is less than 0.1 Ohm between the two test points the bonding is adequate.


    22. Tests to be conducted:


      1. The installer / technician conducting these tests must be certified level VI by UIC ACCC TED.


      2. Test between the TMGB and the service equipment (power) ground.


      3. Test between the TMGB and each TGB in the system.


      4. Test between the TGB and:


        1. Data racks.


        2. Cable tray.


        3. Telecommunication conduit.


        4. Caging.


        5. Electronic equipment.


      5. These tests shall be conducted with the systems in operation.


      6. These tests shall be recorded on sheets provided for this purpose by UIC ACCC TED.
Back
Table of Content
 Next


2002-9-11  ACCC Webstaff
UIC Home Page Search UIC Pages Contact UIC