JOINT STANDARD
ANSI-J-STD-607-A-2002 Approved October 22, 2002
Commercial Building Grounding (Earthing) and Bonding Requirements For Telecommunications J-STD-607-A OCTOBER 2002
Jointly Developed By: TELECOMMUNICATIONS TELECOMMUNICATI ONS INDUSTRY ASSOCIATION The Telecommunications Industry Association represents the communications sector of
Sponsored by the
NOTICE
Standards and Publications are adopted in accordance with the American National Standards Institute Institute (ANSI) patent policy. By such action, the Telecommunications Industry Association or the Alliance for Telecommunications Industry Solutions or its sponsored Committee Committee T1 does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard or Publication. This Standard does not purport to address all safety problems associated with its use o r all applicable regulatory requirements. requirements. It is the responsibility responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use.
(From Project No. 3-4351, formulated under the cognizance of the TIA TR-41.7 Subcommittee and Committee T1.) Published by TELECOMMUNICATIONS S �TELECOMMUNICATION
INDUSTRY ASSOCIATION 2002 Standards & Technology Department 2500 Wilson Boulevard, Suite 300 Arlington, VA 22201 Or
�ALLIANCE
FOR TELECOMMUNICATIONS INDUSTRY SOLUTIONS 1200 G Street, NW Suite 500 Washington, DC 20005 (202) 628-6380 All rights reserved Printed in U.S.A.
NOTICE
Standards and Publications are adopted in accordance with the American National Standards Institute Institute (ANSI) patent policy. By such action, the Telecommunications Industry Association or the Alliance for Telecommunications Industry Solutions or its sponsored Committee Committee T1 does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard or Publication. This Standard does not purport to address all safety problems associated with its use o r all applicable regulatory requirements. requirements. It is the responsibility responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use.
(From Project No. 3-4351, formulated under the cognizance of the TIA TR-41.7 Subcommittee and Committee T1.) Published by TELECOMMUNICATIONS S �TELECOMMUNICATION
INDUSTRY ASSOCIATION 2002 Standards & Technology Department 2500 Wilson Boulevard, Suite 300 Arlington, VA 22201 Or
�ALLIANCE
FOR TELECOMMUNICATIONS INDUSTRY SOLUTIONS 1200 G Street, NW Suite 500 Washington, DC 20005 (202) 628-6380 All rights reserved Printed in U.S.A.
NOTICE FROM THE DEVELOPERS
This document has been approved by the Telecommunications Telecommunications Industry Association (TIA) Engineering Engineering Committee and the Alliance for Telecommunications Industry Solutions (ATIS) sponsored Committee T1 – Telecommunications. Telecommunications. Users may submit comments to the Standards Secretariat of TIA at the following address: 2500 Wilson Boulevard, Boulevard, Suite 300, Arlington, Arlington, VA VA 22201-3438; Telephone: 703/9077700; FAX: 703/907-7728. This document is being published by Global Engineering on behalf of TIA and ATIS on behalf of Committee T1. This document was coordinated between ATIS’ ATIS’ Committee T1 and TIA. A Word from TIA
TIA/EIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his/her particular need. Existence of such Standards and Publications Publications shall not in any respect preclude preclude any member or nonmember of TIA/EIA from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than TIA/EIA members, whether the standard is to be used either domestically or internationally. A Word from ATIS Committee T1
Established in February 1984, Committee T1 develops technical standards, reports and requirements regarding interoperability interoperability of telecommunications networks at interfaces with with end- user systems, carriers, carriers, information and enhanced-service providers, a nd customer premises premises equipment (CPE). (CPE). Committee T1 is sponsored sponsored by ATIS and is accredited by ANSI. This document is issued under a joint copyright by ATIS and TIA. TIA. No part of this publications may be reproduced in any form, in an electronic retrieval retrieval system or otherwise, without prior written permission of ATIS. For information contact ATIS at 202/628-6380.
NOTICE OF COPYRIGHT
This document is issued under a joint copyright by the Telecommunications Industry Industry Association and the Alliance for Telecommunications Industry Solutions, and may not be reproduced without permission. Organizations may obtain permission to reproduce a limited number of copies by entering into a license license agreement. For information, information, contact: Global Engineering Documents Documen ts 15 Inverness Way East Englewood, CO 80112-5704 or call U.S.A. and Canada (1-800-854-7179) International International (303) 37-7956 37- 7956 Or ATIS Document Center: www.atis.org Alliance for Telecommunications Industry Solutions 1200 G Street, NW NW Suite 500 Washington, Washington, DC 20005 (202) 628-6380 NOTICE FROM PATENT HOLDERS
The user’s attention is called to the possibility that compliance with this standard may require use of an invention covered by patent rights. By publication of this standard, no position is taken with respect to the validity of this claim or of any patent rights in connection therewith. The patent holder has, however, filed a statement of willingness to grant a license under these rights on reasonable and nondiscriminatory terms and conditions to applicants desiring to obtain a license. Details may be obtained from the Telecommunications Industry Association, Alliance for Telecommunications Telecommunications Industry Solutions or the American National Standards Institute. �Copyright
Telecommunications Industry Association 2002
All rights reserved This document is subject to change.
NOTICE OF DISCLAIMER AND LIMITATION OF LIABILITY
The document to which this Notice is affixed has been prepared by one or more Engineering Committees of the Telecommunications Industry Association (“TIA”). In addition the document was balloted by Committee T1. Neither TIA nor ATIS is the author of the document contents, but both publish and claim copyright to the document pursuant to licenses and permission granted by the authors of the contents. TIA Engineering Committees are expected to conduct their affairs in accordance with the TIA Engineering Manual (“TIA Manual”), the current and predecessor versions of which are available at http://www.tiaonline.org http://www.tia online.org/standards/sfg /standards/sfg/engineering /engineering_manual. _manual.cfm cfm.. Committee T1 is expected to conduct their affairs in accordance with the Committee T1 Procedures Manual which is available at ftp://ftp.t1.org/pub/t1/t1-proc.pdf . TIA’s function is to administer the process, but not the content, of document preparation in accordance with the Manual and, when appropriate, the policies and procedures of the American National Standards Institute (“ANSI”). Likewise, ATIS’ function, as the Committee T1 Secretariat, is to administer the process according according to the Committee Committee T1 Procedures Procedures Manual, but not develop develop the the content content of the document. document. THE USE OR PRACTICE OF CONTENTS OF THIS DOCUMENT MAY INVOLVE THE USE OF INTELLECTUAL PROPERTY RIGHTS (“IPR”), INCLUDING PENDING OR ISSUED PATENTS, OR COPYRIGHTS, OWNED BY ONE OR MORE PARTIES. NEITHER TIA NOR ATIS MAKES ANY SEARCH OR INVESTIGATION FOR IPR. WHEN IPR CONSISTING OF PATENTS AND PUBLISHED PATENT APPLICATIONS ARE CLAIMED AND CALLED TO TIA’S ATTENTION, A STATEMENT FROM THE HOLDER THEREOF IS REQUESTED, ALL IN ACCORDANCE WITH THE TIA MANUAL. WHEN IPR CONSISTING OF PATENTS ARE CLAIMED AND CALLED TO ATIS’ ATTENTION, A STATEMENT FROM THE HOLDER THEREOF IS REQUESTED, ALL IN ACCORDANCE WITH THE ATIS MANUAL. NEITHER TIA NOR ATIS TAKES A POSITION WITH REFERENCE TO, AND DISCLAIMS ANY OBLIGATION TO INVESTIGATE OR INQUIRE INTO, THE SCOPE OR VALIDITY OF ANY CLAIMS OF IPR. ALL WARRANTIES, EXPRESS OR IMPLIED, ARE DISCLAIMED, INCLUDING WITHOUT LIMITATION, ANY AND ALL WARRANTIES CONCERNING THE ACCURACY OF THE CONTENTS, ITS FITNESS OR APPROPRIATENESS FOR A PARTICULAR PURPOSE OR USE, ITS MERCHANTABILITY AND ITS NON-INFRINGEMENT OF ANY THIRD PARTY’S INTELLECTUAL PROPERTY RIGHTS. TIA AND ATIS BOTH, INDIVIDUALLY, EXPRESSLY DISCLAIM ANY AND ALL RESPONSIBILITIES FOR THE ACCURACY OF THE CONTENTS AND MAKES NO REPRESENTATIONS OR WARRANTIES REGARDING THE CONTENT’S COMPLIANCE WITH ANY APPLICABLE STATUTE, RULE OR REGULATION. NEITHER TIA NOR ATIS SHALL BE LIABLE FOR ANY AND ALL DAMAGES, DIRECT ORINDIRECT, ARISING FROM OR RELATING TO ANY USE OF THE CONTENTS CONTAINED HEREIN, INCLUDING WITHOUT LIMITATION ANY AND ALL INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING DAMAGES FOR LOSS OF BUSINESS, LOSS OF PROFITS, LITIGATION, OR THE LIKE), WHETHER BASED UPON BREACH OF CONTRACT, BREACH OF WARRANTY, TORT (INCLUDING NEGLIGENCE), PRODUCT LIABILITY OR OTHERWISE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. THE FOREGOING NEGATION OF DAMAGES IS A FUNDAMENTAL ELEMENT OF THE USE OF THE CONTENTS HEREOF, AND THESE CONTENTS WOULD NOT BE PUBLISHED BY TIA OR ATIS WITHOUT SUCH LIMITATIONS.
J-STD-607-A
CONTENTS FOREWORD.................................................................................................................iv 1 INTRODUCTION....................................................................................................... 1 1.1 General ................................................................................................................ 1 1.2 Purpose ............................................................................................................... 2 1.3 Expected usefulness........................................................................ .................... 2 1.4 Code-related sources........................................................................................... 3 1.5 Normative and supplementary elements .............................................................. 3 1.6 Mandatory and advisory terms ............................................................................. 3 1.7 Metric equivalents of U.S. customary units .......................................................... 3 1.8 Life of this Standard............................................................................................. 3 2 SCOPE ...................................................................................................................... 5 2.1 General............................................................................................................... 5 2.2 Exclusions from this Standard............................................................................. 7 2.3 Normative references.......................................................................................... 7 2.4 Other references............................................ ..................................................... 8 3 DEFINITIONS ........................................................................................................... 9 3.1 General............................................................................................................... 9 3.2 Definition of terms ............................................................................................... 9 3.3 Abbreviations and acronyms............................................................................. 11 3.4 Units of measure............................................................................................... 12 4 OVERVIEW OF TELECOMMUNICATIONS GROUNDING (EARTHING) AND BONDING SYSTEMS ................................................................................................. 13 4.1 General............................................................................................................. 13 4.2 Overview of the telecommunications grounding and bonding infrastructure...... 13 5 COMPONENTS OF THE TELECOMMUNICATIONS GROUNDING (EARTHING) AND BONDING INFRASTRUCTURE ......................................................................... 15 5.1 General............................................................................................................. 15 5.2 The telecommunications main grounding busbar (TMGB) ................................ 16 5.3 Bonding conductor for telecommunications....................................................... 18 5.4 The telecommunications bonding backbone (TBB) and the grounding equalizer (GE) ......................................................................................................................... 18 5.5 The telecommunications grounding busbar (TGB) ............................................ 20 5.6 Bonding to the metal building frame.................................................................. 21 6 TELECOMMUNICATIONS ENTRANCE FACILITY ................................................. 23 6.1 General............................................................................................................. 23 6.2 Placing the telecommunications main grounding busbar (TMGB) ..................... 23 6.3 Other attachments to the telecommunications main grounding busbar (TMGB) 23 6.4 Other grounding busbars .................................................................................. 24 6.5 Other service entrances.................................................................................... 24 7 TELECOMMUNICATIONS ROOM AND EQUIPMENT ROOM................................ 25 7.1 General............................................................................................................. 25 7.2 Multiple telecommunications grounding busbars (TGBs) .................................. 25 7.3 Placing the telecommunications grounding busbar (TGB)................................. 25 7.4 Other connections to telecommunications grounding busbar (TGB) .................. 25 8 WORK AREA........................................................................................................... 26 9 TOWERS AND ANTENNAS .................................................................................... 27
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9.1 General .............................................................................................................. 27 Annex A (informative).................................................................................................. 28 Cross-Reference of Terms....................................................................................... 28 Annex B (informative).................................................................................................. 29 Telecommunications electrical protection – primary protector grounding ................. 29 Annex C (informative) ................................................................................................ 31 Towers and antennas .............................................................................................. 31 C.1 General ............................................................................................................. 31 C.2 Antenna Locations............................................................................................. 31 C.3 Types of Support Structures............................................................................. 31 C.4 Structure grounding requirements ..................................................................... 32 C.5 Sites with Wood Poles...................................................................................... 32 C.6 Roof-Mounted Towers ...................................................................................... 33 C.7 Down Conductors ............................................................................................. 33 C.8 Roof Conductors .............................................................................................. 34 C.9 Radial Grounding Conductors .......................................................................... 34 C.10 Waveguide and coaxial cable grounding requirements................................... 34 C.11 Equipment Building Grounding Requirements................................................ 35 Annex D (informative) ................................................................................................ 37 Work Area................................................................................................................ 37 D.1 Co-location of electrical power and telecommunications grounding facilities ..... 37 D.2 Electrical protection for operator-type equipment positions .............................. 37 Annex E (informative).................................................................................................. 39 References .............................................................................................................. 39
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FIGURES Figure 2.1-1 Scope of standard for large commercial buildings ............................ 6 Figure 2.1-2 Scope of standard for smaller commercial buildings ......................... 7 Figure 5.1-1 Label for grounding and bonding conductors .................................... 15 Figure 5.2-1 Typical main grounding busbar (TMGB)............................................ 16 Figure 5.3-1 Bonding to the service equipment (power) ground ............................ 18 Figure 5.5-1 Typical grounding busbar (GB) ......................................................... 19 Figure D.2-1 Electrical protection for operator-type equipment positions .............. 36
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FOREWORD (This foreword is not part of this Standard) This joint TIA/T1 Standard was produced by TIA/EIA Working Group 41.7.2 in close coordination with ATIS T1E1.5 and T1E1.7. This joint Standard is published in accordance with the TIA Style Manual. Approval of Standard This Standard was approved by TIA/EIA Technical Committees TR-41, ATIS Committee T1 and the American National Standards Institute (ANSI). Contributing Organizations During the development of the original Standard, subject matter experts were gathered under the auspices of the Electronic Industries Alliance / Telecommunications Industry Association (EIA/TIA) to determine the minimum commercial building grounding and bonding infrastructure necessary to support, from a functional perspective, the variety of telecommunications equipment and systems found in many of today’s commercial buildings. This Standard has been revised as an ongoing effort between TIA Engineering Committee TR 41, Environmental Considerations Technical Subcommittee TR 41.7, and the Alliance for Telecommunications Industry Solutions (ATIS), Committee T1, Technical Subcommittee T1E1, Power Systems W orking Group T1E1.5 and Electrical Protection Working Group T1E1.7. Through this joint revision process, a broader telecommunications industry perspective has been achieved by bringing together telecommunications subject matter experts in the areas of central office and customer location grounding and bonding, r epresenting manufacturers, users, and individuals active in other standards organizations. Documents Superceded This Standard replaces the first edition of ANSI/EIA/TIA 607, originally published in August 1994. Significant technical changes and additions from the previous edition include: -- Greater grounding busbar detail. -- Tower and antenna grounding and bonding recommendations. -- W ork area and personal operator-type equipment position grounding and bonding recommendations. -- Revised, harmonized terminology. Terminology from the National Electrical Code (NEC) has been retained. There are five annexes to this Standard. All annexes are informative and are not considered part of this Standard.
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This standard replaces ANSI/EIA/TIA-607 Commercial Building Grounding and Bonding Requirements for Telecommunications. ANSI/EIA/TIA-607 is hereby rescinded. Suggestions for improvement of this Standard are welcome. They should be addressed to: Telecommunications Industry Association Engineering Department 2500 Wilson Blvd. Suite 300 Arlington, VA 22201-3834
At the time this Standard was approved, the joint TIA TR-41.7.2 Commercial Building Grounding and Bonding / T1E1 DC Power (T1E1.5) and Electrical Protection (T1E1.7) Working Groups had the following members: Jim Romlein, MIS Labs, Chair TR 41.7.2 P. E. Pool, Chair - T1E1.7 J. E. Brunssen, Vice-Chair - T1E1.7 R. Witherill, Chair - T1E1.5 N. Tullius, Vice-Chair - T1E1.5 Gregory Bain Donna Ballast Goeran Benjamin Steven Bipes George Borkowicz William Bush Marshall L. Cain G.W. Crane T. G. Croda Phillip Havens Bob Jensen Ralph E. Jensen Ray Keden Paul Kreager Stephen Kuba
Paul Kish Ronald Lai R. Langhage Gerry Monacelli Don Murray Jim Nienhuis Joe O’Brien Larry C. Payne Debbie R. Ryon Edward J. Silverman Greg Steinman Tom Varga Chris Wellborn Larry Young
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COMMERCIAL BUILDING GROUNDING (EARTHING) AND BONDING REQUIREMENTS FOR TELECOMMUNICATIONS 1 INTRODUCTION 1.1 General 1.1.1 Grounding (earthing) and bonding is important for reliable operation of telecommunications equipment and systems. Commercial buildings are often planned and constructed with incomplete knowledge of eventual building telecommunications equipment and systems. The telecommunications grounding and bonding system infrastructure is frequently designed and installed long before occupant and equipment needs are established. Despite these unknowns, the building grounding and bonding infrastructure is frequently placed during original building construction. It must be capable of supporting a multivendor, multiproduct environment and not be specific to particular equipment or systems. 1.1.2 Modern telecommunications requires an effective building infrastructure to support the wide variety of systems that rely on the electronic transport of information. This infrastructure encompasses telecommunications spaces, pathways, cables, connecting hardware, and the telecommunications grounding and bonding system. This infrastructure provides the basic support for the distribution of electronic information within the building. This Standard provides guidelines for the grounding and bonding portion of this infrastructure. Telecommunications, as used in this Standard, refers to all forms of information that are conveyed within the building (e.g., voice, data, video, environmental control, security, audio, etc.) 1.1.3 The grounding and bonding approach recommended in this Standard is intended to work in concert with the cabling topology as specified in ANSI/TIA/EIA-568-B.1-B.3 (Commercial Building Telecommunications Cabling Standard), pathways as specified in ANSI/TIA/EIA-569-A (Commercial Building Standard for Telecommunications Pathways and Spaces), administration as specified in ANSI/EIA/TIA-606 (Administration Standard for the Telecommunications Infrastructure of Commercial Buildings), and customer owned outside plant as specified in ANSI/TIA/EIA-758 (Customer Owned Outside Plant). The requirements specified in this Standard, in conjunction with a basic understanding of grounding and bonding concepts and methodologies will aid the user in achieving a reliable electrical solution when applied to specific telecommunications installations. 1.1.4 Compliance with the National Electrical Code (NEC) and local codes mandated by the authority having jurisdiction is essential for the proper application of this Standard. 1.1.5 The North American term “grounding” used in this Standard is equivalent to the accepted international term “earthing”.
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1.2 Purpose 1.2.1 The purpose of this Standard is to enable the planning, design, and installation of telecommunications grounding and bonding systems within a building with or without prior knowledge of the telecommunications systems that will subsequently be installed. This Standard also provides recommendations for grounding and bonding of customer owned towers and antennas. This telecommunications grounding and bonding infrastructure supports a multivendor, multiproduct environment as well as various system installation practices. 1.2.2 A large resource of information exists within the telephone industry in the form of telephone utility company guidelines and proprietary practices. The NEC covers the safety aspects of grounding and bonding of telecommunications equipment and systems; ANSI T1.318, Electrical Protection Applied to Telecommunications Network Plant and Entrances to Customer Structures or Buildings , provides information on grounding and bonding as necessary to support electrical protection considerations. However, prior to the original release of ANSI/TIA/EIA 607, there were no U. S. standards for telecommunications grounding and bonding in commercial buildings. This reissued Standard continues to provide a uniform telecommunications grounding and bonding infrastructure that supports simple and reliable deployment of telecommunications equipment and systems in a commercial building environment.
1.3 Expected usefulness 1.3.1 This Standard will be useful to anyone engaged in the design, maintenance, renovation, or retrofit of new or existing commercial buildings. 1.3.2 This Standard will be useful to manufacturers of telecommunications equipment. 1.3.3 This Standard will be useful to service providers or others purchasing, installing, or operating telecommunications equipment and devices. 1.3.4 This Standard may be used for specification of the exact interface points between the building electrical systems and the telecommunications grounding and bonding system. It may be used for specifying exact building grounding and bonding system configurations. 1.3.5 This Standard will be useful to building owners and developers who want to build an advanced technology structure that is compatible with modern telecommunications equipment. 1.3.6 A benefit of a telecommunications grounding and bonding infrastructure, as described in this Standard, is a reliable ground reference for telecommunications systems.
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1.4 Code-related sources This Standard does not replace any code, either partially or wholly. The reader should also be aware of local codes that might impact the use of this Standard.
1.5 Normative and supplementary elements TIA standards differentiate between normative and supplementary elements. Normative elements are those elements setting out the provisions with which it is necessary to comply in order to be able to claim conformity with this Standard. Supplementary elements are informative elements that provide additional information intended to assist in the understanding or use of this Standard.
1.6 Mandatory and advisory terms 1.6.1 Two categories of criteria, mandatory and advisory, are specified. The mandatory requirements are designated by the word "shall"; advisory requirements are designated by the word "should," "may," or "desirable" (which are used interchangeably in this document). 1.6.2 Mandatory criteria generally apply to protection, performance, and compatibility; they specify the absolute minimum acceptable requirements. Advisory or desirable criteria generally represent product goals. In some instances, these criteria are included in an effort to ensure product compatibility and universal facilities. In other cases, advisory criteria are presented when their attainment will enhance the general performance of the product in all its contemplated applications. 1.6.3 Where both a mandatory and an advisory level are specified for the same criterion, the advisory level represents a goal currently identifiable as having distinct compatibility or performance advantages, or both, toward which future designs should strive. 1.6.4 A note in a table or figure is an official part of this Standard. A note in the text is used only for giving information. 1.6.5 Citations of other documents refer to the latest revision unless specifically dated or otherwise noted.
1.7 Metric equivalents of U.S. customary units The majority of metric dimensions in this Standard are soft conversions of U.S. customary units; e.g., 4 inches equals 100 mm.
1.8 Life of this Standard
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1.8.1 This Standard is a living document. The criteria contained in this Standard are subject to revision and updating as warranted by advances in building construction techniques and telecommunications technologies. 1.8.2 TIA reviews most standards every five years. At that time standards are reaffirmed, rescinded, or revised according to the submitted updates. Update recommendations for inclusion in the next revision should be sent to the secretariat of TIA at the address shown in the forward.
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2 SCOPE 2.1 General 2.1.1 This Standard specifies the requirements for a uniform telecommunications grounding and bonding infrastructure that shall be followed within commercial buildings where telecommunications equipment will be installed. 2.1.2 This Standard specifies a telecommunications grounding and bonding infrastructure and its interconnection to other building systems. 2.1.3 Figure 2.1-1 depicts the scope of the telecommunications grounding and bonding infrastructure for larger, multi-story commercial buildings with multiple telecommunications backbones. Figure 2.1-2 depicts a smaller commercial building where telecommunications spaces are combined. This Standard specifies the requirements for: --A ground (earth) reference for telecommunications systems within the telecommunications entrance facility, the telecommunications room, and equipment room; --Bonding of metallic pathways, cable shields, conductors, and hardware at telecommunications rooms, equipment rooms, and entrance facilities. 2.1.4 This Standard is intended to encourage planning, which should include grounding and bonding arrangements to accommodate telecommunications equipment installation. 2.1.5 While primarily intended to provide direction for design of new commercial buildings, this Standard may be used as a guide for the renovation or retrofit of existing buildings. 2.1.6 Design requirements and choices are described to enable the designer to make informed design decisions.
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Telecommunications Room (TR)
Telecommunications Room (TR)
Grounding Equalizer (GE)
Equipment
Equipment
TGB
TGB
Metal Frame of Building
Pathways
Telecommunications Room (TR)
Telecommunications Room (TR)
Equipment
Equipment
TGB
TGB
Telecommunications Bonding Backbone (TBB) Electrical Entrance Facility
Telecommunications Entrance Facility (TEF)
Equipment Room (ER)
Equipment Equipment Telecommunications Main Grounding Busbar (TMGB) Grounding Electrode Conductor Grounding Electrode System
Bonding conductor for telecommunications
Telecommunications Grounding Busbar (TGB)
LEGEND
Cross connect
Panelboard
Grounding bar
Outside scope of this standard
Service equipment
Bonding conductor as labeled
Figure 2.1-1 Scope of the standard for large commercial buildings
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Electrical Entrance Facility
LEGEND
Telecommunications Entrance Facility (TEF)
Cross connect Grounding bar
Telecommunications Equipment
Telecommunications Main Grounding Busbar (TMGB) Grounding Electrode Conductor
Service equipment
Panelboard Outside scope of this standard Bonding conductor as labeled
Bonding conductor for teleommunications
Grounding Electrode System
Figure 2.1-2 Scope of standard for smaller commercial buildings
2.2 Exclusions from this Standard This Standard does not provide requirements for: a) b) c) d) e) f) g) h) i) j) k)
Specific grounding and bonding of any telecommunications equipment and associated wiring; Values of surge current immunity and insulation withstand voltages; Methods for verifying and maintaining grounding and bonding networks; Specific methods for RFI/EMI mitigation for equipment or systems; Primary protector/arrester specifications, applications and installation; Secondary protector specifications and applications; Specific user safety; Grounding and bonding practices of the local telecommunications utilities; Electrical service entrance; Grounding of ac surge protection devices; Buildings with more than one electrical service entrance.
2.3 Normative references The following standards contain provisions that, through reference in this text, constitute provisions of this Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. ANSI and TIA maintain registers of currently valid national standards published by them. -- ANSI/TIA/EIA 568-B.1-B.3, Commercial Building Telecommunications Cabling Standard ; -- ANSI/TIA/EIA 569-A, Commercial Building Standard for Telecommunications Pathways and Spaces;
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-- ANSI/TIA/EIA 606, Administration Standard for the Telecommunications Infrastructure of Commercial Buildings; -- ANSI/TIA/EIA 758, Customer Owned Outside Plant ; -- ANSI/NFPA-70, 2002, National Electrical Code.
2.4 Other references For applications requiring more stringent specifications than provided by this Standard such as security, electromagnetic interference, or protection fr om electromagnetic pulse, the reader is referred to other standards described in Annex E.
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3 DEFINITIONS 3.1 General This clause contains definitions of terms, acronyms, abbreviations, units of measure, and symbols that have a special meaning or that are unique to the technical content of this Standard. The terms that are used in only one clause may be defined within, and at the beginning of, that clause.
3.2 Definition of terms For the purposes of this Standard, the following definitions apply: antenna entrance: A pathway facility from the antenna to the associated equipment. backbone: A facility (e.g. pathway, cable or conductors) between telecommunications rooms, or floor distribution terminals, the entrance facilities, and the equipment rooms within or between buildings. bonding: The permanent joining of metallic parts to form an electrically conductive path that will assure electrical continuity and the capacity to conduct safely any current likely to be imposed. bonding conductor for telecommunications: A conductor that interconnects the telecommunications bonding infrastructure to the building's service equipment (power) ground. commercial building: A building or portion thereof that is intended for office use. connecting hardware: A device providing mechanical cable terminations. earthing: An international term that is equivalent to grounding. See ground. effectively grounded: Intentionally connected to earth through a ground connection or connections of sufficiently low impedance and having sufficient current-carrying capacity to prevent the buildup of voltages that may result in undue hazard to connected equipment or to persons. electrical closet: A floor-serving facility for housing electrical equipment, panelboards, and controls. entrance facility (telecommunications): An entrance to a building for both public and private network service cables (including antennae) including the entrance point at the building wall and continuing to the entrance room or space.
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entrance point (telecommunications): The point of emergence of telecommunications conductors through an exterior wall, a concrete floor slab, or from a rigid metal conduit or an intermediate metal conduit. entrance room or space (telecommunications): A space in which the joining of interor intrabuilding telecommunications backbone facilities takes place. NOTE - An entrance room may also serve as an equipment room. equipment room (telecommunications): An centralized space for telecommunications equipment that serves the occupants of the building. NOTE – An equipment room is considered distinct from a telecommunications room because of the nature or complexity of the equipment. exothermic weld: A method of permanently bonding two metals together by a controlled heat reaction resulting in a molecular bond. ground: A conducting connection, whether intentional or incidental, between an electrical circuit or equipment and the earth, or to some conducting body that serves in place of the earth. grounding electrode conductor : The conductor used to connect the grounding electrode to the equipment grounding conductor, to the grounded conductor, or to both, of the circuit at the service equipment, or at the source of a separately derived system. grounding electrode system: An electrode(s) as specified in the National Electrical Code, Article 250. grounding equalizer (GE): The conductor that interconnects elements of t he telecommunications grounding infrastructure (formerly TBBIBC). infrastructure (telecommunications): A collection of those telecommunications components, excluding equipment, that together provide the basic support for the distribution of all information within a building or campus. listed: Equipment included in a list published by an organization, acceptable to the authority having jurisdiction, that maintains periodic inspection of production of listed equipment, and whose listing states either that the equipment meets appropriate standards or has been tested and found suitable for use in a specified manner. pathway: A facility for the placement of telecommunications cable. primary protector : The protector located at the building telecommunications entrance point and listed under ANSI/UL 497. primary protector grounding conductor : The conductor used to connect the primary protector either to the TMGB or to the telecommunications grounding (earthing) and bonding system.
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protector : A device consisting of one or more protector units intended to limit abnormal surges on metallic communications circuits. Includes a mounting assembly for the protector units. protector unit: A device intended to protect against either overvoltage or overcurrent, or both. The unit may contain carbon arresters, gas tubes, solid state devices, heat coils, PTC devices, or a combination of these components for a specific application. room (telecommunications): An enclosed space for housing telecommunications equipment, cable terminations, and cross-connect cabling, that is the recognized location of the cross-connect between the backbone and the horizontal facilities. telecommunications: Any transmission, emission, and reception of signs, signals, writings, images, and sounds, that is information of any nature by cable, radio, optical, or other electromagnetic systems. telecommunications bonding backbone: A conductor that interconnects the telecommunications main grounding busbar (TMGB) to the telecommunications grounding busbar (TGB). telecommunications bonding backbone interconnecting bonding conductor : See grounding equalizer. telecommunications equipment room: See equipment room (telecommunications). telecommunications infrastructure: See infrastructure (telecommunications). telecommunications grounding busbar : The interface to the building telecommunications grounding system generally located in telecommunications room. A common point of connection for telecommunications system and equipment bonding to ground, and located in the telecommunications room or equipment room. telecommunications main grounding busbar : A busbar placed in a convenient and accessible location and bonded by means of the bonding conductor for telecommunications to the building service equipment (power) ground. telecommunications room: See room, telecommunications. termination hardware: See connecting hardware.
3.3 Abbreviations and acronyms ac ACEG AWG BICSI ATIS CISPR CSA dc
alternating current alternating current equipment ground American Wire Gage A Telecommunications Association Alliance for Telecommunications Industry Solutions International Special Committee on Radio Interference Canadian Standards Association International direct current
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EF EIA EMI EMT ESD GB GE NRTL NEC NEMA NFPA PBG SBC SBTC ScTP STP T1E1 TBB TEF TER TGB TIA TMGB TR UTP
entrance facility Electronic Industries Alliance electromagnetic interference electrical metallic tubing electrostatic discharge grounding bar grounding equalizer national recognized testing laboratory National Electrical Code National Electrical Manufacturers Association National Fire Protection Association principal building ground solid bare copper conductor solid bare tinned copper screened twisted pair shielded twisted pair T1 Technical Subcommittee telecommunications bonding backbone telecommunications entrance facility telecommunications entrance room telecommunications grounding busbar Telecommunications Industry Association telecommunications main grounding busbar telecommunications room unshielded twisted pair
3.4 Units of measure A dB o C o F ft Hz in J kg kHz km lbf m mm ppm Vac Vdc Ω
ampere decibel degrees Celsius degrees Fahrenheit feet, foot hertz inch joule kilogram kilohertz kilometer pound force meter millimeter parts per million volts alternating current volts direct current ohm
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4 OVERVIEW OF TELECOMMUNICATIONS GROUNDING (EARTHING) AND BONDING SYSTEMS 4.1 General 4.1.1 The basic principles, components, and design methods of the telecommunications grounding and bonding infrastructure specified in this Standard shall be followed amongst buildings of differing design and structure. 4.1.2 This clause specifies the telecommunications grounding and bonding infrastructure, identifies the different elements that make up the infr astructure, and describes their interrelations. The following clauses provide the detailed requirements associated with each of the components. 4.1.3 When secondary protection is provided, the secondary protector grounding conductor shall be connected to the nearest telecommunications grounding busbar (e.g., telecommunications main grounding busbar (T MGB) or telecommunications grounding busbar (TGB)), using the shortest grounding conductor practicable. 4.1.4 While the grounding and bonding of the electrical service entrance is outside the scope of this Standard, coordination between electrical and telecommunications grounding and bonding systems is essential for the proper application of this Standard. 4.1.5 In all cases the applicable electrical codes for grounding and bonding for telecommunications shall be met.
4.2 Overview of the telecommunications grounding and bonding infrastructure 4.2.1 The telecommunications grounding and bonding infrastructure originates at the service equipment (power) ground and extends throughout the building. It includes the following major components: a) b)
Telecommunications main grounding busbar (TMGB); Bonding conductor for telecommunications;
and may also include the following: c) d) e)
Telecommunications Bonding Backbone (TBB); Grounding Equalizer (GE); Telecommunications grounding busbar (TGB).
4.2.2 These telecommunications grounding and bonding components are intended to work in concert with telecommunications pathways and spaces ( ANSI/TIA/EIA 569-A), cabling ( ANSI/TIA/EIA 568-B.1-B.3), and administration ( ANSI/EIA/TIA-606), including, when present:
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a) b) c) e) f)
Telecommunications Entrance Facility (TEF); Telecommunications Equipment Room (TER); Telecommunications Room (TR); Telecommunications cable and connecting hardware; Telecommunications labeling and record keeping.
4.2.3 Although the electrical closet and associated panelboard(s) are not part of the telecommunications infrastructure, they are depicted in this Standard because they are integral to the telecommunications grounding and bonding system.
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5 COMPONENTS OF THE TELECOMMUNICATIONS GROUNDING (EARTHING) AND BONDING INFRASTRUCTURE 5.1 General 5.1.1 This section describes the characteristics of the major components of the telecommunications grounding and bonding infrastructure. 5.1.2 All grounding and bonding connectors shall be listed by a nationally recognized testing laboratory (NRTL) as required by the NEC. Note: Connectors are listed for the application (e.g., above ground or direct buried.) 5.1.3 All grounding and bonding conductors shall be copper and may be insulated. When conductors are insulated, they shall be listed for the application. The minimum bonding conductor size shall be a No. 6 AWG. Note: Conductors are listed for the space in which they are intended to be placed, such as riser systems or plenum spaces. 5.1.4 Grounding and bonding conductors should not be placed in ferrous metallic conduit. If it is necessary to place grounding and 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 using a grounding bushing or a No. 6 AWG conductor, minimum. 5.1.5 Labeling, color-coding, and marking 5.1.5.1 Each telecommunications grounding and bonding conductor shall be labeled. Labels shall be located on conductors as close as practicable to their point of termination in a readable position. Labels shall be nonmetallic and include the information depicted in figure 5.1-1. Refer to ANSI/TIA/EIA 606 for additional labeling requirements.
IF THIS CONNECTOR OR CABLE IS LOOSE OR MUST BE REMOVED, PLEASE CALL THE BUILDING TELECOMMUNICATIONS MANAGER Figure 5.1-1 Label for grounding and bonding conductors
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5.1.5.2 The Bonding Conductor for Telecommunications, each telecommunications bonding backbone (TBB) conductor, and each grounding equalizer (GE), shall be green or marked with a distinctive green color.
5.2 The telecommunications main grounding busbar (TMGB) 5.2.1 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 the telecommunications bonding backbone(s) (TBB) and equipment. Typically, there should be a single TMGB per building. Note: For buildings with more than one electrical service entrance, each of which serves telecommunications equipment, the user is urged to consult with a licensed engineer. 5.2.2 The ideal location of the TMGB is in the telecommunications entrance facility. However, the TMGB should be located to minimize the length of the bonding conductor for telecommunications. 5.2.3 The TMGB should serve telecommunications equipment that is located within the same room or space. 5.2.4 Extensions of the TMGB (i.e., other telecommunications busbars in other telecommunications spaces) shall be TGBs. 5.2.5 Description of the telecommunications main grounding busbar (TMGB) 5.2.5.1 The TMGB shall: a) be a predrilled copper busbar provided with holes for use with standard sized lugs; b) be sized in accordance with the immediate application requirements and with consideration of future growth; c) have minimum dimensions of 6 mm (0.25 in) thick x 100 mm (4 in) wide and variable in length; d) be listed by a nationally recognized testing laboratory. 5.2.5.2 It is desirable that the busbar be electrotin plated for reduced contact resistance. If not plated, the busbar shall be cleaned prior to fastening of conductors and an anti-oxidant should be applied to the contact area to control corrosion and reduce contact resistance. Figure 5.2-1 depicts a typical TMGB.
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16 mm (5/8 in) typ
8 mm (5/16 in) typ dia.
13 mm (1/2 in)
11 mm dia. (7/16 in), typ 25 mm (1 in)
100 mm (4 in) min. 29 mm (1-1/8 in) typ
50 mm (2 in)
29 mm 11 mm dia. (1-1/8 in) (7/16 in) typ mounting holes, typ
Figure 5.2-1 Typical telecommunications main grounding busbar (TMGB)
5.2.6 Bonding to a panelboard for telecommunications equipment 5.2.6.1 Where a panelboard (electrical power panel) is located in the same room or space as the TMGB that panelboard’s alternating current equipment ground (ACEG) bus (when equipped) or the panelboard enclosure shall be bonded to the TMGB. 5.2.6.2 The TMGB shall be as close to the panelboard as practicable and shall be installed to maintain clearances required by applicable electrical codes. 5.2.7 Connections to the telecommunications main grounding busbar (TMGB) 5.2.7.1 The connections of the bonding conductor for telecommunications and the TBB to the TMGB shall utilize exothermic welding, listed compression two-hole lugs, suitable and equivalent one hole non-twisting lugs, or other irreversible compression type connections. Two-hole lugs are preferred. 5.2.7.2 The connection of conductors for bonding telecommunications equipment to the TMGB shall utilize exothermic welding, listed compression lugs, or other irreversible compression type connections. Two-hole lugs are preferred. 5.2.7.3 All metallic raceways for telecommunications cabling located within the same room or space as the TMGB shall be bonded to the TMGB. However for metallic pathways containing grounding conductors where the pathway is bonded to the grounding conductor, no additional bond to the TMGB is required. 5.2.8 Installation requirements 5.2.8.1 The TMGB shall be insulated from its support. A minimum of 50 mm (2 in) separation from the wall is recommended to allow access to the r ear of the busbar. 5.2.8.2 The TMGB shall be located such that it is accessible to telecommunications personnel. A practical location for the TMGB is to the side of the panelboard (where provided). The mounting height of the TMGB should be adjusted to accommodate
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overhead or underfloor cable routing. Also see 6.2.1.
5.3 Bonding conductor for telecommunications 5.3.1 Bonding to the service equipment (power) ground The bonding conductor for telecommunications shall bond the TMGB to the service equipment (power) ground. Figure 5.3-1 schematically depicts this connection to the service equipment (power) ground.
Telecommunications Entrance Facility
Electrical Entrance Facility Service Equipment
TB B
N
Equipment G
Grounding Electrode Conductor
Bonding conductor for telecommunications
TMGB
Outside the scope o f this Standard Within the scope of this Standard
Figure 5.3-1 Bonding to the service equipment (power) ground
5.3.2 Sizing the bonding conductor for telecommunications The bonding conductor for telecommunications shall be, as a minimum, the same size as the TBB.
5.4 The telecommunications bonding backbone (TBB) and the grounding equalizer (GE) 5.4.1 The TBB is a conductor that interconnects all TGBs with the TMGB. 5.4.2 The TBB originates at the TMGB extends throughout the building using the telecommunications backbone pathways, and connects to the TGBs in all telecommunications rooms and equipment rooms. The GE interconnects multiple TBBs. 5.4.3 Description of the telecommunications bonding backbone (TBB) and the grounding equalizer (GE) 5.4.3.1 The TBB should be designed with consideration given to the type of building construction, building size, general telecommunications requirements, and the
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configuration of the telecommunications pathways and spaces. Specifically, the design of a TBB shall: --be consistent with the design of the telecommunications backbone cabling system; --permit multiple TBBs as dictated by the building size; --address routing to minimize the lengths of the TBBs. 5.4.3.2 The interior water piping system of the building shall not be used as a TBB. 5.4.3.3 The metallic cable shield shall not be used as a TBB. 5.4.3.4 Whenever two or more TBBs are used within a multistory building, the TBBs shall be bonded together with a GE (formerly known as telecommunications bonding backbone interconnecting bonding conductor) at the top floor and at a minimum of every third floor in between. The GE shall be sized as specified in 5.4.4.1. 5.4.4 Bonding and sizing the telecommunications bonding backbone (TBB) 5.4.4.1 The TBB shall be a copper conductor. The minimum TBB conductor size shall be a No. 6 AWG. The TBB should be sized at 2 kcmil per linear foot of conductor length up to a maximum size of 3/0 AWG. The TBB may be insulated. If the TBB is insulated, the insulation shall meet the fire ratings of its pathway. The sizing of the TBB is not intended to account for the reduction or control of electromagnetic interference. Sizing of the TBB TBB length TBB Size (AWG) linear m (ft) less than 4 (13) 6 4 – 6 (14 – 20) 4 6 – 8 (21 – 26) 3 8 – 10 (27 – 33) 2 10 – 13 (34 – 41) 1 13 – 16 (42 – 52) 1/0 16 – 20 (53 – 66) 2/0 greater than 20 (66) 3/0 Figure 5.4.4.1 - Sizing of the TBB 5.4.4.2 The TBB shall be connected to the TMGB as specified in 5.2.7.1. The intended function of a TBB is to reduce or equalize potential differences between telecommunications systems. While the TBB will carry some current under ac power ground fault conditions, it is not intended to provide the only ground fault return path. A TBB is not intended to serve as the only conductor providing a ground fault current return path. 5.4.5 Installation considerations
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5.4.5.1 The TBB conductors shall be installed and protected from physical and mechanical damage. 5.4.5.2 The TBB conductors should be installed without splices. Where splices are necessary, the number of splices should be a minimum and they shall be accessible and located in telecommunications spaces. Joined segments of a TBB shall be connected using exothermic welding, irreversible compression-type connectors, or equivalent. All joints shall be adequately supported and protected from damage.
5.5 The telecommunications grounding busbar (TGB) The TGB is the grounding connection point for telecommunications systems and equipment in the area served by that telecommunications room or equipment room. 5.5.1 Description of the telecommunications grounding busbar (TGB) 5.5.1.1 The TGB shall: --be a predrilled copper busbar provided with holes for use with standard sized lugs, and --have minimum dimensions of 6 mm (0.25 in) thick x 50 mm (2 in) wide and variable length to meet the application requirements and with consideration of future growth. -- be listed by a nationally recognized testing laboratory. 5.5.1.2 It is desirable that the busbar be electrotin-plated for reduced contact resistance. If not plated, the busbar shall be cleaned prior to fastening the conductors to the busbar, and an anti-oxidant should be applied to the contact area to control corrosion and reduce contact resistance. Figure 5.5-1 depicts a typical telecommunications grounding busbar (TGB).
16 mm (5/8 in)
8 mm (5/16 in) dia.
11 mm (7/16 in) dia.
13 mm (1/2 in)
11 mm (7/16 in) dia.
25 mm (1 in)
50 mm (2 in)
mounting holes
29 mm (1-1/8 in)
Figure 5.5-1 Typical telecommunications grounding busbar (TGB)
5.5.2 Bonds to the telecommunications grounding busbar (TGB) 5.5.2.1 The TBBs and other TGBs within the same space shall be bonded to the TGB with a conductor the same size as the TBB.
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5.5.2.2 The bonding conductor between a TBB and a TGB shall be continuous and routed in the shortest possible straight-line path. 5.5.2.3 Where a panelboard (electrical power panel) for telecommunications equipment is located within the same room or space as the TGB, that panelboard’s ACEG bus (when equipped) or the panelboard enclosure shall be bonded to the TGB. 5.5.2.4 The TGB shall be as close to the panelboard as is practicable and shall be installed to maintain clearances required by applicable electrical codes. 5.5.2.5 Where a panelboard for telecommunications equipment 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. 5.5.2.6 The TGB shall be bonded to the GE where required per 5.4.3.4. 5.5.2.7 All metallic raceways for telecommunications cabling located within the same room or space as the TGB shall be bonded to the TGB. 5.5.3 Connections to the telecommunications grounding busbar (TGB) 5.5.3.1 Connections of the TBB and the GE to the TGB shall utilize exothermic weld connections, listed compression two hole lugs connectors, suitable and equivalent onehole non-twisting lugs or other irreversible compression type connectors. Two-hole connectors are preferred. 5.5.4 Installation considerations 5.5.4.1 The TGB shall be insulated from its support. A minimum of 50 mm (2 in) separation from the wall is recommended to allow access to the r ear of the busbar. 5.5.4.2 A practical location for the TGB is to the side of the panelboard (where provided). The vertical location of the TGB should take into consideration whether the bonding conductors are routed in an access floor or overhead cable tray.
5.6 Bonding to the metal building frame 5.6.1 All connectors used for bonding to the metal frame of a building shall be listed for the intended purpose. 5.6.2 In a metal frame (structural steel) building, where the steel framework is readily accessible within the room; each TGB and TMGB shall be bonded to the vertical steel metal frame using a minimum No. 6 AW G conductor. 5.6.3 Where the metal frame is external to the room and readily accessible, the metal frame should be bonded to the TGB or TMGB with a minimum No. 6 AWG conductor.
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5.6.4 When practicable because of shorter distances and, where horizontal steel members are permanently electrically bonded to vertical column members, the TGB may be bonded to these horizontal members in lieu of the vertical column members. 5.6.5 This Standard does not require bonding of the steel bars of a reinforced concrete building to the TGB or TBB.
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6 TELECOMMUNICATIONS ENTRANCE FACILITY 6.1 General 6.1.1 The telecommunications entrance facility (TEF) is the entrance point (room or space within the building) where: -- the telecommunications facilities enter, -- the joining of inter- and intrabuilding backbone facilities takes place, and -- the grounding (earthing) of these facilities is accomplished. The TEF may also include antenna cable entrances, and electronic equipment serving telecommunications functions. 6.1.2 It is desirable that all utilities enter the building in close proximity to each other. Refer to Annex B.
6.2 Placing the telecommunications main grounding busbar (TMGB) 6.2.1. The TEF is the desirable location for the telecommunications main grounding busbar (TMGB). The TMGB may also serve as the telecommunications grounding busbar (TGB) for equipment in the TEF. 6.2.2 The TMGB should be placed to provide for the shortest and straightest routing of the primary protector grounding conductor. See Annex B. 6.2.3 The TMGB is the common point in the TEF for all telecommunications grounding connections in that room or space. 6.2.4 The TMGB shall be placed as close as practicable to the panelboard for telecommunications equipment and shall be installed to maintain clearances required by applicable electrical codes. 6.2.5 When a panelboard for telecommunications equipment is not installed in the TEF, the TMGB should be located near the backbone cabling and associated terminations. In addition, the TMGB should be located so that the bonding conductor for telecommunications is as short and straight as possible.
6.3 Other attachments to the telecommunications main grounding busbar (TMGB) 6.3.1 The primary protector grounding conductor shall be connected to the TMGB. This conductor is intended to conduct lightning and ac fault currents from the telecommunication primary protectors. A minimum of 300 mm (1 ft) separation shall be maintained between this insulated conductor and any dc power cables, switchboard
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cable, or high frequency cables, even when placed in rigid metal conduit or EMT. Also see 5.2.8.2. 6.3.2 When the outside plant cables in the TEF incorporate a cable shield isolation gap, the cable shield on the building side of the gap shall be bonded to the TMGB. 6.3.3 In buildings where the backbone cable incorporates a shield or metallic member, this shield or metallic member shall be bonded to the TMGB or TGB. 6.3.4 Telecommunications primary protectors for the interbuilding backbone cables shall be bonded to the TMGB. 6.3.5 All metallic pathways for telecommunications cabling located within the same room or space as the TMGB shall be bonded to the TMGB. However, for metallic pathways containing grounding conductors where the pathway is bonded to the grounding conductor, no additional bond to the TMGB is required.
6.4 Other grounding busbars The TMGB is intended to be the location for connecting grounding busbars incorporated in telecommunications equipment located in the TEF (e.g., multiplexer or optical fiber termination equipment).
6.5 Other service entrances Where antenna cables enter a building, the point of entry should be treated as an entrance facility. Where an entrance facility is located at the roof, a TGB shall be provided in accordance with entrance facility requirements.
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7 TELECOMMUNICATIONS ROOM AND EQUIPMENT ROOM 7.1 General Each telecommunications room and equipment room shall contain a telecommunications grounding busbar (TGB). The TGB shall be located inside the room. The TGB shall be located so as to provide the greatest flexibility and accessibility for telecommunications system grounding, (minimizing lengths and number of bends of the bonding conductor to the TGB, but within the constraints of Clause 5).
7.2 Multiple telecommunications grounding busbars (TGBs) Multiple TGBs may be installed within the same telecommunications room to aid in minimizing bonding conductor lengths and terminating space. In all cases, multiple TGBs within a room shall be bonded together with a conductor the same size as the TBB or with splice bars.
7.3 Placing the telecommunications grounding busbar (TGB) The TGB shall be placed per 5.5.2.4. Where a panelboard for telecommunications equipment is not installed in the telecommunications room, the TGB should be located near the backbone cabling and associated terminations. In addition, the TGB should be placed to provide for the shortest and straightest routing of the grounding conductors.
7.4 Other connections to telecommunications grounding busbar (TGB) 7.4.1 In buildings where the backbone telecommunications cabling incorporates a shield or metallic member, this shield or metallic member shall be bonded to the TGB where the cables are terminated or where pairs are broken out. 7.4.2 All metallic pathways for telecommunications cabling located within the same room or space as the TGB shall be bonded to the TGB. However, for metallic pathways containing grounding conductors where the pathway is bonded to the grounding conductor, no additional bond to the TGB is required. 7.4.3 Short metallic pathways (e.g. wall and floor sleeves) are not required to be bonded.
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8 WORK AREA Work area grounding is beyond the scope of this Standard. For information, refer to Annex D.
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9 TOWERS AND ANTENNAS 9.1 General For minimum tower and antenna grounding specifications refer to Annex C (Informative). It is anticipated that the requirements in this Standard, which address grounding for commercial buildings, will differ from commercial service provider requirements, which are specified in T1.313-1998. The document T1.313-1998 specifications support a very robust level of service appropriate to a service provider. Users of this Standard are encouraged to refer to T1.313-1998 where robust service requirements exist.
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Annex A (informative) Cross-reference of terms Preferred terms used in this Standard Telecommunications Main Grounding Busbar (TMGB)
Telecommunications Grounding Busbar (TGB) Telecommunications Bonding Backbone (TBB)
Grounding Equalizer (GE)
Other industry terms Building Principal Ground (BPG) CO GRD Bus COG Facility Ground Main Earthing Terminal (MET) Master Ground Bar (MGB) OPGPB PGP Bus Principal Ground Point (PGP) Reference Point 0 (RP0 Zero Potential Reference Point) Extended Reference Point 0 (Extended RP0) Floor Ground Bar (FGB) Approved Floor Ground Equalizer Equalizing Conductor Grounding Equalizer (GE) Vertical Equalizer Vertical Ground Riser Horizontal Equalizer Telecommunications Bonding Backbone Interconnecting Bonding Conductor (TBBIBC)
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Annex B (informative) Telecommunications electrical protection – primary protector grounding B.1 Telecommunications network plant is often subject to electrical disturbances arising from lightning and commercial ac power line faults. To help safeguard persons and property from the effects of these disturbances, primary telecommunications electrical protection is placed at the telecommunications entrance to the building or structure by the network telecommunications utility access provider. The National Electrical Code (NEC) specifies the minimum primary protection requirements, and states that “the primary protector shall be located in, on, or immediately adjacent to the structure or building served and as close as practicable to the point at which the exposed conductors enter or attach.” The network telecommunications utilities, in addition to conforming to the NEC requirements, also provide primary telecommunications electrical protection where they deem their network plant potentially exposed to lightning or commercial ac power disturbances. One exception is urban areas where tall, steel-framed buildings provide shielding from lightning, the large mass of underground metallic structures dissipates lightning energy, and power conductors are placed underground in conduit separate from telecommunications conductors. In such areas, primary telecommunications electrical protection is generally not necessary as there is no lightning or power exposure. B.2 A critical consideration when placing the primary protector is the length of the primary protector grounding conductor. The primary protector grounding (earthing) conductor provides the grounding path between the primary protector ground terminal and the building or structure power grounding electrode system. During a lightning event to the network telecommunications plant, substantial voltages can be developed in the primary protector grounding conductor. The magnitude of the voltage is dependent both on the waveshape of the lightning surge and the impedance of the grounding conductor which is directly proportional to conductor length. For this reason, network telecommunications utility practices recommend: -- Locating the telecommunications entrance as close as practicable to the power entrance to minimize the length of the primary protector grounding conductor. The NEC also emphasizes this by requiring a means for intersystem bonding between power and other systems, such as telecommunications systems. -- Placing the primary protector to allow for the shortest and most direct routing of the primary protector grounding conductor. B.3 While the telecommunications network is only one means by which lightning voltages can be introduced into a building or structure (power phase conductors, the power neutral conductor, and a strike to the building itself are others), maximum effort should be made to keep the primary protector grounding conductor as short as possible. This may be accomplished by locating the primary protector in close proximity to the power service entrance at the building or structure. In addition to the primary protector grounding conductor, the overall conductor path between the primary protector and the power service ground should be kept as short as possible. This path may include the Bonding Conductor for Telecommunications as illustrated in Figures 2.1-1 and 2.1-2 of
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this Standard. The length of the Bonding Conductor for Telecommunications may be minimized by locating the telecommunications main grounding busbar (TMGB) as close as practicable to the electrical entrance facility. B.4 Requirements for telecommunications electrical protection, grounding and bonding at building or structure entrances are contained in the NEC, Chapter 8, Communications Systems. Additional detailed electrical protection, grounding and bonding considerations and criteria are contained in ANSI T1.318-1994, Electrical Protection Applied to Telecommunications Network Plant at Entrances to Customer Structures or Buildings. The reader is directed to these documents for guidance regarding the primary protector, and the placement, routing, and length of the primary protector grounding conductor
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Annex C
(informative)
Towers and antennas C.1 General This section describes specific electrical protection considerations for antenna support structures (towers).
C.2 Antenna locations C.2.1 Antennas can be mounted on wood or metal supports. In some cases, the antenna support structures (towers) are mounted on the roof of a building. Mounting towers or antennas on a roof could damage the structural integrity of the building and/or void the warranty of the roof. C.2.2 Occasionally, the antenna might be mounted on the side wall of a building or on a parapet wall using special braces or supports. C.2.3 The presence of an antenna and its supporting structure on the roof of a building is not expected to significantly increase the probability of lightning striking the building. However, if lightning does strike, the antenna and its supporting tower may be the focal point of the strike.
C.3 Types of support structures Typical antenna support structures (towers) include: -- guyed metallic, -- self-supporting metallic, -- wooden structures (poles). The towers can be installed at grade level (surface), on building roofs or side walls. C.3.1 Guyed metallic towers These are structures with upright support members (legs) mounted on a foundation or pier that require multiple anchors and down guys. C.3.2 Self-Supporting metallic towers These are free-standing structures with upright support members (legs) mounted on a foundation or pier that need no other supporting elements. C.3.3 Wooden structures (poles)
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These are either free-standing or guyed structures either mounted on a foundation or partially buried.
C.4 Structure grounding requirements C.4.1 All towers and satellite dish mountings should have a grounding electrode system consisting of a ground ring and ground rods. C.4.2 A #2 AWG solid, bare copper (SBC) conductor should be buried around the tower at a minimum depth of 760 mm (30 in) below grade, and at least 610 mm (24 in) from the base of the tower or mounting. The ends of the #2 AWG conductor should be connected using exothermic welding or a listed connector to form a continuous ring. C.4.3 Driven ground rods minimum 2.5 m (8 ft) in length and 16 mm (5/8 in) diameter should be placed at the base of each tower leg, a minimum of 460 mm (18 in) below grade. The connection of the ground rods to the ground ring should be accomplished using exothermic welding or listed connectors. Ground rods should be copper, copper clad steel, stainless steel, or zinc clad steel. C.4.4 The base of each tower leg should be bonded to the ground ring with a #2 AWG conductor. The bonding conductor should be as short and straight as possible. C.4.5 The metallic frame supporting a satellite dish should be bonded to the ground ring with a #2 AWG conductor, which should be as short and straight as possible. C.4.6 For monopole or guyed towers, there should be at least two ground rods, driven a minimum of 25 mm (1 in) below grade, equally spaced, and connected to the ground ring using exothermic welding or listed connectors. Grounds of monopole tower mounted antennas should be connected to the ground ring with a #2 AWG SBC conductor using exothermic welding or listed connectors. C.4.7 The tower ground ring should be bonded to the equipment building ground ring, described in clause C.11.1 with at least two #2 AWG SBC conductors buried at a minimum depth of 760 mm (30 in) between the tower and building ground rings. C.4.8 If there is a metal fence within 1.8 m (6 ft) of the tower, the tower ground ring should be bonded to the fence with a #2 AWG SBC conductor. C.4.9 Similar rules apply for bonding a monopole or satellite-mounting ground ring to the equipment building ground ring or fence.
C.5 Sites with wood poles C.5.1 In some cases, a site consists only of a wood pole supporting the antenna and the radio equipment cabinet.
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C.5.2 All wood poles should have a #2 AWG SBC vertical ground wire terminating in either ground rods, or radials. C.5.3 Common bonding and grounding principles used on separate building and tower sites also apply in this case. In addition, the following requirements must be met: C.5.3.1 Any electric power conduit should extend and terminate above any telephone attachment (cable, wire, or drop) at a point where the weatherhead is near the power circuit attachments or warning light. C.5.4 The conduit from the weatherhead to the power meter should be at least 6 m (20 ft) long. This aids the operation of the power arrester at the weatherhead.
C.6 Roof-mounted towers C.6.1 When the antenna support or tower is mounted on the roof of a building, a grounding system should be designed that meets the following clauses: C.6.1.1 Uses regular lightning protection cables and hardware following the recommendations of the NPFA-780 Standard for the Installation of Lightning Protection Systems. C.6.1.2 Places a wire ring (roof ring) around the antenna support or tower. C.6.1.3 Connects the tower base footings to the: -- Tower ground ring. -- Waveguide, or coaxial, outer conductor. -- Lighting AC branch circuit metallic conduit and green wire (ACEG). -- Lightning arrester ground. C.6.1.4 Connects: -- Antenna metal members to the tower or antenna support structure. -- Antenna support structure to ring. -- Lightning protection system perimeter wires. -- Ring to any other metallic object on the roof within flashover range. NOTE: Coordinate the lightning protection system of the building and the grounding system for the tower.
C.7 Down conductors C.7.1 A roof-mounted tower or antenna mast of any size should have at least two down conductors from opposite sides of the roof ground ring down the building wall to connect to either a buried ground ring around the building (preferred), or two or more rods.
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C.7.2 Additional down conductors are needed for each 30 m (100 ft) of building length. NOTE: These down conductors are in addition to the ones used in the lightning protection system.
C.8 Roof conductors C.8.1 Roof conductors should be supported every 1 m (3 ft) using either no-nail paste down cable fasteners, or pan-type base ridge cable supporters.
C.9 Radial grounding conductors C.9.1 Radials should be provided if ground rods cannot be driven and it is not feasible to drill. When radial grounding conductors are necessary, the following should be used to determine requirements: C.9.1.1 When towers are constructed on sites where bedrock prevents placing ground rods, a network of buried grounding conductors should be provided radiating from each base of the antenna and building corner and connecting to the ground rings. C.9.2 When radial grounding conductors are required a #2 AWG SBC conductor connected to the ground ring and buried at least 760 mm (30 in) below grade level should be used. C.9.3 If adequate contact cannot be reached with the soil at 7.6 m (25 ft), extend each radial wire as far as necessary to obtain the desired resistance. The conductor length should not be less than 7.6 m (25 ft). NOTE: Low resistance in radial grounding arrangements is desirable but not essential. Low resistance in the dissipating path of strike currents into the earth is of secondary importance when compared to the major objective of controlling voltage gradients and voltage differences between structures close to the radio equipment.
C.10 Waveguide and coaxial cable grounding requirements C.10.1 Waveguide and coaxial cable shields should be bonded to the tower at the top and bottom of the tower. If the tower is greater than 60 m (200 ft) in height, the waveguide or coax shield should also be bonded at the tower midpoint or every 15 m (50 ft). C.10.2 Where the waveguide or coaxial cable enters the building, the waveguide or coaxial shield should be bonded to the building’s external grounding electrode system with a #2 AWG conductor. Once inside the building, the waveguide or coaxial cable shield should be bonded to the building’s interior grounding electrode system, using a #2 AWG conductor, as close as practical to the entrance.
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C.10.3 If there is a metallic waveguide or coaxial cable entrance plate, the entrance plate should be bonded to both the exterior and interior grounding system with a #2 AWG conductor. The waveguide or coaxial cable shield should be bonded to the metallic entrance plate on both the outside and inside of the building with a #2 AWG conductor. C.10.4 The coaxial cable should be protected by a lightning surge arrester, which is bonded to the exterior grounding electrode system with the proper size grounding conductor specified by the manufacturer. C.10.5 If the tower is lighted, the conduit for the lighting power conductors should be bonded and grounded as described for waveguide and coaxial cable shields.
C.11 Equipment building grounding requirements C.11.1 When the equipment building is located atop a building, grounding for externally mounted system metallic components including antennas, cabling, conduits, cable trays, entry ports, window frames and door frames is a critical requirement. Externally mounted wireless components should be grounded to the building lightning protection system, which may include bonding to down conductors or building steel, or may employ an independent system to achieve adequate grounding. C.11.2 Special grounding procedures should be followed for buildings that house radio equipment. Radio equipment buildings should have an exterior ground ring consisting of #2 AWG bare wire buried a minimum of 760 mm (30 in) below grade and at least 610 mm (2 ft) from any portion of the structure. The ends of the wire should be joined with an exothermic connection or listed connectors to f orm a continuous ring. C.11.3 Ground rods, driven to a minimum cover depth of 460 mm (18 in) should be placed at 3 - 4.5 m (10 – 15 ft) intervals and connected directly to the ground ring with exothermic connections or listed connectors. C.11.4 The equipment building ground ring should be bonded to the tower ground ring, described in section C.4, with at least two #2 AWG SBC conductors. C.11.5 If there is a metal fence within 1.8 m (6 ft) of the building, the building ground ring should be bonded to the fence with a #2 AWG SBC conductor. C.11.6 Radio equipment buildings with nonmetallic walls should have an interior ground ring consisting of a #2 AWG conductor mounted, with nonmetallic connections, to the interior wall within 0.3 m (1 ft) of the ceiling. C.11.7 Radio equipment buildings with metallic walls should have an interior ground ring consisting of a #2 AWG conductor mounted directly to the interior wall within 0.3 m (1 ft) of the ceiling.
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C.11.8 The interior ground ring should be bonded to the exterior ground ring with #2 AWG conductor, routed as straight as possible, using exothermic connections or listed connectors.
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Annex D
(informative)
Work Area D.1 Co-location of electrical power and telecommunications grounding facilities D.1.1 Telecommunications equipment is often connected to both the electrical power and telecommunications grounding systems. It is important that both grounding systems be at the same reference potential. This is critical for implementation of shielded/screened twisted pair cabling systems. ANSI/TIA/EIA 568-B.1-B.3 limits the potential difference between power and telecommunications ground references to a maximum of 1 volt for shielded/screened cable applications.
D.2 Electrical protection for operator-type equipment positions D.2.1 High technology devices are increasingly being implemented at the work area, including one or more computers, phones, printers, etc. In communications-intensive operations, personnel may wear voice headsets connected to headset interface equipment in addition to the typical work area devices. At these locations, personnel use a variety of electronic equipment including a headset, headset interface equipment, other electronic equipment such as a computer keyboard and Video Display Terminal (VDT), and the work station furniture. Frequently, workstations are arranged in clusters consisting of several positions. These positions are typically used at reservation bureaus, telemarketing agencies, and such. Refer to Figure D.2-1. D.2.2 Operator-type equipment positions (workstations) should be grounded in accordance with T1.321-1995 Electrical Protection for Network Operator-type Equipment Positions. D.2.3 Electrical disturbances may appear at operator-type equipment positions arising either from electrostatic discharge (ESD), or fr om sources that are internal or external to the building such as lightning or ac power disturbances. Standard T1.321-1995 Electrical Protection for Network Operator-type Equipment Positions covers new installations of network operator-type equipment positions in which personnel are required to access a computer terminal keyboard while continually wearing a headset. This standard presents measures that are intended to help to control ESD in the network operator-type environment. Standard T1.321 also presents additional measures that are intended to help minimize the effects of lightning, surges from commercial ac power lines, and power switching operations, both at the facility (building) level and at the network operator-type equipment position. These measures provide for equipotential bonding and grounding at the TEF and the power entrance facility (PEF), as well as for equipotential bonding and grounding, where necessary, and electrical protection at the network operator-type equipment positions. Although
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standard T1.321 deals specifically with network locations, the measures outlined in the standard are applicable to non-network installations, as well as at existing installations. D.2.4 The electrical protection measures included in standard T1.321 are intended to minimize potential differences at the network operator-type equipment position (work station) but are not intended to guarantee against damage or injury that may r esult from ESD or other similar occurrences. D.2.5 General electrical safety and protection requirements that may be applied to work areas are contained in the NEC. ACEG provided in supply cords. branch circuit outlet box Video
External surge protective device
Electrical closet
Processor/ controller
Telecommunications Room
Headset interface
Equipment
Position bonding terminal
TGB
Telecommunications Room TBB
External secondary protector unit
Bond to furniture Bond to building steel
Electrical service entrance
Telecommunications entrance facility
TC equipment TMGB Bonding conductor for telecommunications Metal Frame of Building
Fig.D.2-1 Electrical protection for operator-type equipment positions
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Annex E (informative) References E.1 ANSI/IEEE 1100 Recommended Practice for Power and Grounding Sensitive Electronic Equipment in Industrial and Commercial Power Systems (also known as IEEE Emerald Book), Institute of Electrical and Electronic Engineers. E.2 BICSI Telecommunications Distribution Methods Manual, BICSI. E.3 EIA EP-7B, Style Manual for Standards and Publications , Electronic Industries Association. E.4 T1.313-1998 Electrical Protection for Telecommunications Central Offices and Similar Type Facilities E.5 CSA-T529-M91, Design Guidelines for Telecommunications Wiring Systems in Commercial Buildings; E.6 CSA-T530-M90, Building Facilities, Design Guidelines for Telecommunications ; E.7 CSA-T528-M93, Building Facilities and Wiring/Cabling for Telecommunications, Design Guidelines for Administration. E.8 The National Communications System (NCS), Technical Information Bulletin (TIB) 92.15, Grounding and Bonding for Commercial and Government Buildings Conforming to Telecommunications Infrastructure Standards - A Background Report. E.9 MIL-STD-188-124B, Military Standard Grounding, Bonding and Shielding . E.10 Military Handbook 419A, Grounding, Bonding, and Shielding for Electronic Equipment and Facilities, Volumes 1 & 2. E.11 T1.318-1999 Electrical Protection Applied to Telecommunications Network Plant at Entrances to Customer Structures or Buildings. E.12 International Special Committee on Radio Interference (CISPR) Publication 22. E.13 T1.321-1995 (R 2000) Electrical Protection for Network Operator-type Equipment Positions. E.14 ANSI/NPFA-780-1997 Standard for the Installation of Lightning Protection Systems
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For additional information about references, contact the respective organizations at the following addresses: ANSI
American National Standards Institute 430 Broadway New York, NY 10018 USA (212) 642-4900
ATIS
Alliance for Telecommunications Industry Solutions 1200 G Street, NW Suite 500 Washington, D.C. 20005 (202)628-6380
BICSI
BICSI 8610 Hidden River Pkwy. Tampa, FL 33637-1000 USA (813) 979-1991
EIA
Electronic Industry Alliance 2500 Wilson Blvd., Suite 400 Arlington, VA 22201 USA (703) 907-7500
IEEE
Institute of Electrical and Electronic Engineers 445 Hoes Lane PO Box 1331 Piscataway, NJ 08855-1331 USA (800) 678 IEEE
NFPA National Fire Protection Association 1 Batterymarch Park Quincy, MA 02269 USA TIA
Telecommunications Industry Association 2500 Wilson Blvd., Suite 300 Arlington, VA 22201 USA (703) 907-7706
UL
Underwriters Laboratories, Inc. 333 Pfingsten Road Northbrook, IL 60062 USA (847) 272-8800
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