Copyright 2010 by The American Institute of Architects (AIA)

Exclusively published and distributed by Architectural Computer Services, Inc. (ARCOM) for the AIA

SECTION 260526 - GROUNDING AND BONDING FOR TELECOMMUNICATION SYSTEMS

Revise this Section by deleting and inserting text to meet Project-specific requirements.

This Section uses the term "Architect." Change this term to match that used to identify the design professional as defined in the General and Supplementary Conditions.

Verify that Section titles referenced in this Section are correct for this Project's Specifications; Section titles may have changed.

NFPA70 and IEEEC2 include basic grounding requirements for electrical safety. This Section supplements those requirements with additional grounding requirements and with optional grounding methods and materials for both power and electronic systems that go beyond basic minimum safety requirements.

PART 1 - GENERAL

1.1RELATED DOCUMENTS

Retain or delete this article in all Sections of Project Manual.

  1. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division01 Specification Sections, apply to this Section.
  2. Appendix A Figures 7 & 8.

1.2SUMMARY

Retain one of two paragraphs below.

  1. Section Includes: Grounding systems and equipment.
  2. Section includes grounding systems and equipment, plus the following special applications:

Retain one or more subparagraphs below for special grounding applications.

  1. Underground distribution grounding.
  2. Ground bonding common with lightning protection system.

1.3ACTION SUBMITTALS

  1. Product Data: For each type of product indicated.

1.4INFORMATIONAL SUBMITTALS

Retain first paragraph below to require Contractor to provide Drawings that locate significant grounding features. Section017839 "Project Record Documents" and Section017823 "Operation and Maintenance Data" require submittals to be included in those documents for use by maintenance forces throughout the life of the Project.

  1. Informational Submittals: Plans showing dimensioned as-built locations of grounding features specified in "Field Quality Control" Article, including the following:

.

  1. Grounding arrangements and connections for separately derived systems.
  2. Grounding for sensitive electronic equipment.

Coordinate first paragraph below with qualification requirements in Section014000 "Quality Requirements" and as supplemented in "Quality Assurance" Article.

1.5QUALITY ASSURANCE

Retain first paragraph below if Contractor retains testing agency or if Contractor is required to provide services of a qualified testing agency in "Field Quality Control" Article. Qualification requirements are in addition to those specified in Section014000 "Quality Requirements," which also includes the definition for "NRTL" (nationally recognized testing laboratory).

  1. Testing Agency Qualifications: Member Company of NETA or an NRTL.
  2. Testing Agency's Field Supervisor: Currently certified by NETA to supervise on-site testing.
  3. Electrical Components, Devices, and Accessories: Listed and labeled as defined in NFPA70, by a qualified testing agency, and marked for intended location and application.
  4. Comply with UL467 for grounding and bonding materials and equipment.

PART 2 - PRODUCTS

2.1CONDUCTORS

Retain first paragraph below to require one of the two preferred conductor materials permitted by NFPA70; delete to allow Contractor to retain any material that complies with Code. See "Grounding Products" Article in the Evaluations for discussion on alternative materials.

  1. Insulated Conductors: No.6AWG green insulated stranded for 600V unless otherwise required by applicable Code or authorities having jurisdiction.

Retain first paragraph below if Project includes overhead-line work.

Retain paragraph below if size of grounding bus and mounting details are not indicated on Drawings. The default dimension is recommended by BICSI for telecommunications bus bar.

2.2CONNECTORS

  1. Listed and labeled by an NRTL acceptable to authorities having jurisdiction for applications in which used and for specific types, sizes, and combinations of conductors and other items connected.
  2. Bolted Connectors for Conductors and Pipes: Copper or copper alloy, pressure type with at least two bolts.
  1. Pipe Connectors: Clamp type, sized for pipe.
  2. These connectors are to be used for bonding only. No building steel or pipes are to be used for grounding purposes.
  1. Welded Connectors: Exothermic-welding kits of types recommended by kit manufacturer for materials being joined and installation conditions.
  2. Bus-bar Connectors: Mechanical type, cast silicon bronze, solderless compression-type wire terminals, and long-barrel, two-bolt connection to ground bus bar.

2.3GROUNDING BUSBARS:

  1. Grounding Busbars shall be electro tin plated copper ¼” thick and shall be U.L. listed and manufactured for this purpose. Busbars shall be installed on insulators and stainless steel standoff brackets. Provide horizontally where shown on Drawings. Mount busbars at 18" above finished floor. Bus bars shall be as follows:
  2. Telecommunications Main Grounding Busbar (TMGB): Shall be a minimum of 4" high x 24" long. The TMGB shall be equipped with a minimum of 28 pairs of pre-drilled 5/16" diameter holes and 5 pairs of 7/16" diameter holes. The 5/16" hole spacing shall be 5/8" on center and the 7/16" hole spacing shall be 1" on center. The busbar shall meet EIA/TIA 607 standard.
  3. Telecommunications Grounding Busbar (TBG): Shall be a minimum of 2" high x 12" long. The TMGB shall be equipped with a minimum of 6 pairs of pre-drilled 5/16" diameter holes and 3 pairs of 7/16" diameter holes. The 5/16" hole spacing shall be 5/8" on center and the 7/16" hole spacing shall be 1" on center. The busbar shall meet EIA/TIA 607 standard.

PART 3 - EXECUTION

3.1HARDWARE:

  1. Conductors: No.6AWG green insulated stranded conductors will be installed and routed according to Appendix A Figures 7 & 8.

Coordinate first paragraph below with Drawings and with Section260543 "Underground Ducts and Raceways for Electrical Systems."

Retain first paragraph below if grounding bus is required. Coordinate with Drawings.

  1. Grounding Bus: Provide in telecommunication rooms, in rooms housing service equipment, and elsewhere as indicated.
  2. Provide bus on insulated spacers 2 inches (50 mm) minimum from wall, 6 inches (150 mm) above finished floor unless otherwise indicated.
  3. Where needed on both sides of doorways, route grounding conductor up to top of door frame, across top of doorway, and down to specified height above floor; connect to horizontal bus.
  4. Conductor Terminations and Connections:
  5. Pipe and Equipment Grounding Conductor Terminations: Bolted connectors.
  6. Underground Connections: Welded connectors
  7. Connections to Structural Steel: For Telecommunications it is not allowed.
  8. The Telecommunications Grounding system shall remain separate and only connect to the electrical grounding system at the main building ground.

3.2GROUNDING UNDERGROUND DISTRIBUTION SYSTEM COMPONENTS

Grounding practices of the local utility company may differ from requirements in three paragraphs below. Although grounding specified in this article is not for the utility company's use and does not have to comply with its standards, it is possible the utility company may be requested to repair or maintain the line in the future. For this reason, it may be desirable to design some grounding features according to the utility company's standards. Utility companies, for economic reasons, often design to a standard lower than what is appropriate for Project requirements. Alternatively, because of their experience with conditions in their service area, utility companies may design to a higher standard than is required by Code. In addition to Project requirements, evaluate the local utility company's practices and revise paragraphs accordingly. This evaluation is particularly important if Project's underground lines connect with utility lines. Coordinate with Drawings and with Section260543 "Underground Ducts and Raceways for Electrical Systems."

  1. Grounding Manholes and Handholes: Provide a driven ground rod through manhole or handhole floor, close to wall, and set rod depth so 4 inches (100 mm) will extend above finished floor. If necessary, provide ground rod before manhole is placed and provide No.1/0AWG bare, tinned-copper conductor from ground rod into manhole through a waterproof sleeve in manhole wall. Protect ground rods passing through concrete floor with a double wrapping of pressure-sensitive insulating tape or heat-shrunk insulating sleeve from 2 inches (50 mm) above to 6 inches (150 mm) below concrete. Seal floor opening with waterproof, nonshrink grout.
  2. Grounding Connections to Manhole Components: Bond exposed-metal parts such as inserts, cable racks, pulling irons, ladders, and cable shields within each manhole or handhole, to ground rod or grounding conductor. Make connections with No.6AWG minimum, stranded, copper bonding conductor. Train conductors level or plumb around corners and fasten to manhole walls. Connect to cable armor and cable shields according to written instructions by manufacturer of splicing and termination kits.

Retain and revise paragraph below to exceed NFPA70 requirements. If concrete pad is for equipment to be supplied by utility company, revise paragraph to comply with utility company's grounding standards or delete and detail on Drawings.

3.3EQUIPMENT GROUNDING

NFPA70 permits two types of equipment grounding conductors: metallic raceway or cable sheath that encloses supply conductors, and a separate grounding conductor of insulated wire or cable installed with supply conductors. Installation of a separate insulated equipment grounding conductor provides an additional degree of safe operation when compared to relying on raceway or cable sheath for ground continuity. NFPA70 requires separate insulated equipment grounding conductors in some situations and not in others. Retain and revise one of first two paragraphs below to require insulated equipment grounding conductors that exceed NFPA70 requirements. Coordinate with Drawings.

Coordinate first paragraph below with Drawings and with Sections for signal and communication equipment. Revise to suit Project.

  1. Signal and Communication Equipment: In addition to grounding and bonding required by NFPA70, provide a separate grounding system complying with requirements in TIA/ATIS J-STD-607-A.
  2. For telephone, alarm, voice and data, and other communication equipment, provide No.6 AWG minimum green insulated grounding conductor from main building grounding electrode system to each service location, terminal cabinet, wiring closet, and central equipment location.
  3. Service and Central Equipment Locations and Wiring Closets: Terminate grounding conductor on a (6.3-by-100-by-300-mm)grounding busbar. For the Service Entrance Telecommunications Room (TR) provide a TMGB (section 2.4.A.3) and for all other Telecommunications Rooms provide a TGB (section 2.4.A.4).
  4. Terminal Cabinets: Terminate grounding conductor on cabinet grounding terminal.
  5. In the Entrance TR all of the following must be bonded with a No. 6 AWG Bonding Conductor back to the TMGB:

1.The vault splice closure for the entrance telephone cable

2.The telephone building protectors

3.All metallic conduits

4.All data relay racks

In all TRs the following must be bonded with a BC back to the TGB:

1.All metallic conduits

2.All data relay racks

Paragraph below may supplement equipment grounding conductor and may be in excess of NFPA70 requirements. Retain if necessary and coordinate with Drawings.

3.4INSTALLATION

  1. Grounding Conductors: Route along shortest and straightest paths possible unless otherwise indicated or required by Code. Avoid obstructing access or placing conductors where they may be subjected to strain, impact, or damage.
  2. Grounding for Steel Building Structure: The Telecommunications grounding system shall not be grounded using steel building structure.

See Evaluations for discussion on ground rings.

3.5LABELING

  1. Comply with requirements in Section260553 "Identification for Electrical Systems" for instruction signs.
  2. Provide labels at the telecommunications bonding conductor and grounding equalizerand at the grounding electrode conductor where exposed.

3.6FIELD QUALITY CONTROL

Retain one of first three paragraphs below to identify who shall perform tests and inspections. If retaining second option in first paragraph, or if retaining second or third paragraph, retain "Field quality-control reports" Paragraph in "Informational Submittals" Article.

  1. Testing Agency: Engage a qualified testing agency to perform tests and inspections.

Retain first paragraph below to require a factory-authorized service representative to perform inspections, tests, and adjustments.

Retain first paragraph below to describe tests and inspections to be performed.

See Section014000 "Quality Requirements" for retesting and reinspecting requirements and Section017300 "Execution" for requirements for correcting the Work.

  1. Grounding system will be considered defective if it does not pass tests and inspections.
  2. Prepare test and inspection reports.

END OF SECTION 260526

GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS / 260526 - 1