Table of Contents Figure 1.111 Breathing respirator... 1-265 Figure 1.112 Rubber gloves and apron... 1-267 Figure 1.113 Communications perceptions... 1-276 Chapter 2: Planning and Project Management Figure 2.1 Sample site plan... 2-38 Figure 2.2 Sample cross-sectional diagram... 2-39 Figure 2.3 Sample floor plan... 2-40 Figure 2.4 Sample room detail... 2-41 Chapter 3: Installing Supporting Structures Figure 3.1 Typical telecommunications room layout... 3-7 Figure 3.2 Typical telecommunications backboard layout... 3-8 Figure 3.3 Corner installation of plywood backboards... 3-10 Figure 3.4 Installation using toggle bolts in drywall construction... 3-11 Figure 3.5 Plywood installed using toggle bolts... 3-12 Figure 3.6 Plan view of a typical telecommunications room with ladder rack installed on two walls... 3-13 Figure 3.7 Vertical ladder rack... 3-14 Figure 3.8 Typical backboard layout for D-ring installation... 3-15 Figure 3.9 Spools... 3-16 Figure 3.10 Conduits on channel stock... 3-17 Figure 3.11 Equipment rack... 3-19 Figure 3.12 Wall-mounted rack with hinge... 3-21 Figure 3.13 Cable managers... 3-23 Figure 3.14 Equipment rack detail... 3-25 Figure 3.15 Electrical metallic tubing couplings... 3-29 Figure 3.16 Intermediate metal conduit... 3-29 Figure 3.17 Intermediate metalc conduit coupling... 3-30 Figure 3.18 Rigid metal conduit... 3-31 Figure 3.19 Rigid metal conduit coupling... 3-32 Figure 3.20 Cross-section of conduit outside diameter vs. inside diameter... 3-33 Figure 3.21 Metal conduit body... 3-34 Figure 3.22 Innerduct... 3-40 Figure 3.23 Four-inch conduit with three innerducts... 3-41 Figure 3.24 Tubular ladder rack... 3-42 Figure 3.25 Suspended ladder rack... 3-43 Figure 3.26 Wall bracket... 3-44 Figure 3.27 Multilevel ladder rack... 3-45 Figure 3.28 Cable retaining posts... 3-46 2004 BICSI ix ITS Installation Manual, 4th edition
Table of Contents Figure 3.29 Rod-stock cable tray... 3-46 Figure 3.30 Directional transition... 3-47 Figure 3.31 Pipe hanger... 3-51 Figure 3.32 Screw head types... 3-54 Figure 3.33 Open top cable supports (J-hook)... 3-59 Figure 3.34 Compression coupling... 3-61 Figure 3.35 Setscrew coupling... 3-62 Figure 3.36 Conduit hangers... 3-63 Chapter 4: Pulling Cable Figure 4.1 Example of marked job floor plans with common symbols... 4-11 Figure 4.2 Area secured with safety cones and caution tape... 4-14 Figure 4.3 Bullwheel and pulley hangers... 4-15 Figure 4.4 Large reel and adjustable jack stands... 4-16 Figure 4.5 Cable tree... 4-18 Figure 4.6 Vacuum blowing a ball or a bag... 4-22 Figure 4.7 Vacuuming a ball... 4-23 Figure 4.8 Attaching pole rope to the cables... 4-25 Figure 4.9 Minimum bending radius... 4-26 Figure 4.10 Beam clamps, J-hooks, and bridge rings... 4-29 Figure 4.11 Telescoping pole... 4-30 Figure 4.12 Large reel and adjustable jack stands... 4-36 Figure 4.13 Cable tree... 4-36 Figure 4.14 Rolling hitch knot... 4-37 Figure 4.15 A cable brake attached to the cable reel... 4-40 Figure 4.16 A pull rope attached to the cable lead... 4-41 Figure 4.17 Bullwheel... 4-42 Figure 4.18 Vertical backbone cable support... 4-43 Figure 4.19 Cable on tray from vertical pathway... 4-44 Figure 4.20 Backboard layout with D-rings... 4-45 Figure 4.21 Wire mesh grips... 4-51 Figure 4.22 Winch in position and properly secured to a concrete slab... 4-52 Figure 4.23 A properly secured pulley... 4-53 Figure 4.24 Swivel to prevent cable twisting... 4-58 Figure 4.25 Four-inch conduit with three innerducts... 4-62 Figure 4.26 Connecting aramid yarn... 4-63 Figure 4.27 Multiweave wire mesh grip with swivel pulling eye... 4-63 ITS Installation Manual, 4th edition x 2004 BICSI
Section 2: Structured Cabling System Chapter 1: Background Information Generic Structured Cabling System, continued Other sections in this chapter provide details about local area networks (LANs), metropolitan area networks (MANs), wide area networks (WANs), and other types of networks that involve cabling installations. The only type of cabling installation presented in this document is an installation within a single building. OSP systems are addressed in the BICSI Customer-Owned Outside Plant (CO-OSP) Design Manual. A structured cabling system includes most or all of the following components: Entrance facilities (EFs) Backbone pathways Backbone cabling Horizontal pathways Horizontal cabling Telecommunications outlets/connectors Equipment rooms (ERs) Telecommunications rooms (TRs) Telecommunications enclosures (TEs) Cross-connect facilities Termination hardware Administration (labeling and documentation) Multi-user telecommunications outlet assemblies (MUTOAs) Transition points (TPs) Consolidation points (CPs) Centralized cabling 2004 BICSI 1-13 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 2: Structured Cabling System Entrance Facility (EF) The EF includes the cabling components needed to provide a means to connect the outside plant facilities to building cabling. This can include the following: Entrance pathways Cables Connecting hardware Primary (electrical) protection devices Transition hardware The access provider (AP) is generally responsible for the installation of regulated facilities, including the items listed above, to a specified point of demarcation, which is the interface between the AP s facility and the customer. For purposes of this manual, the ITS cabling installer is responsible for extending services from the demarcation point throughout the building cabling system. In the United States, EF pathways and spaces are specified in TIA-569-B, Commercial Building Standard for Telecommunications Pathways and Spaces. In other countries, they are specified in ISO/IEC 18010, Information Technology Pathways and Spaces for Customer Premises Cabling, or similar national documents. Refer to the section on standards later in this chapter for more information. An EF is expected to provide the following: Point of demarcation between the APs and customer premises cabling (if required). Primary (electrical) protection devices governed by the applicable electrical codes. Space to house the transition between OSP cabling and building cabling. This usually involves transition from unlisted cable to listed cable. A designer should specify the EF, including the pathways and spaces, and cabling and connecting hardware. Refer to Section 3: Codes, Standards, and Regulations in this chapter and National Fire Protection Association (NFPA) 70 National Electrical Code (NEC ) for details. Designers and cabling installers outside the United States should refer to the appropriate codes, standards, and regulations. ITS Installation Manual, 4th edition 1-14 2004 BICSI
Section 3: Codes, Standards, and Regulations Chapter 1: Background Information Codes Affecting Information Transport Systems (ITS) in North America Codes address the safety of persons, property, and the environment associated with the ITS cabling installation. They include electrical codes, building codes, fire codes, environmental codes, and all other safety codes. When adopted by AHJs, codes have the force of law. The National Electrical Code (NEC ) and the Canadian Electrical Code (CE Code) are the most widely adopted set of electrical safety requirements within North America. In addition, state, provincial, municipal, and local codes may add more restrictive provisions than the national codes and, therefore, take precedence. The order of code compliance should be in full conformance to national, state, and local codes, with the most restrictive code taking precedence. In Mexico, the national electrical code is known as NOM-001-SEDE-1999, Instalaciones Eléctricas (Utilización). This code is revised every five years. The next edition is expected to be published in late 2004 and will be known as NOM-001-SEDE-2004. The National Fire Protection Association (NFPA) develops and produces codes and standards relating to ITS that include the NEC. The Canadian Standards Association (CSA ) publishes the CE Code. National Fire Protection Association (NFPA) The NFPA develops and produces the following fire and safety codes relating to ITS: NFPA 70, National Electrical Code (NEC ), 2005 NFPA 70E, Electrical Safety in the Workplace, 2004 NFPA 72, National Fire Alarm Code, 2002 NFPA 75, Standard for the Protection of Electronic Computer/Data Processing Equipment, 2003 NFPA 76, Recommended Practice for the Fire Protection of Telecommunications Facilities, 2002 NFPA 90A, Installation of Air-Conditioning and Ventilating Systems, 2002 NFPA 101, Life Safety Code, 2003 NFPA 255, Standard Method of Test of Surface Burning Characteristics of Building Materials, 2000 NFPA 262, Standard Method of Test for Flame Travel and Smoke of Wires and Cables for Use in Air-Handling Spaces, 2002 NFPA 780, Standard for the Installation of Lightning Protection Systems, 2004 NFPA 5000, Building Construction and Safety Code, 2003 2004 BICSI 1-51 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 3: Codes, Standards, and Regulations National Fire Protection Association (NFPA), continued National Electrical Code (NEC ) The NFPA sponsors, controls, and publishes the NEC within the U.S. jurisdictional area. The NEC is intended to protect persons and property from electrical hazards. The NEC specifies minimum provisions necessary to safeguard persons and property from electrical hazards. In the United States, most federal, state, and local municipalities have adopted the NEC in whole or in part as their legal electrical code. Some states or localities adopt the NEC and add more stringent requirements. Local jurisdiction determines the current version recognized and does not always adopt the latest edition. The NEC (revised every three years) is used by: Lawyers and insurance companies to determine liability. Fire marshals and electrical inspectors in loss prevention and safety enforcement. In buildings that will contain the ITS systems, NEC requirements do not necessarily address the adequate electrical environment for reliable and error-free operation of the installed equipment. Additional considerations beyond those necessary for safety are described in performance standards and in the appropriate sections of this manual. Table 1.4 lists NEC chapters, articles, and subarticles that apply to ITS. Table 1.4 National Electrical Code chapters, articles, and subarticles that impact ITS installation NEC Reference Article 90 Subarticle 90.2 Subarticle 90.3 Article 100 Article 110 Subarticle 110.26 Subarticle 110.32 Subarticle 110.33 Subarticle 110.34 Article 210 Subarticle 210.25 Article 225 Subarticle 225.14 Title Introduction Scope Code Arrangement Definitions Requirements for Electrical Installations Spaces About Electrical Equipment Work Space About Equipment Entrance and Access to Work Space Work Space and Guarding Branch Circuits Common Area Branch Circuits Outside Branch Circuits and Feeders Open-Conductor Spacings ITS Installation Manual, 4th edition 1-52 2004 BICSI
Section 3: Codes, Standards, and Regulations Chapter 1: Background Information National Fire Protection Association (NFPA), continued Table 1.4, continued National Electrical Code chapters, articles, and subarticles that impact ITS installation NEC Reference Article 250 Subarticle 250.32 Subarticle 250.50 Subarticle 250.60 Subarticle 250.70 Subarticle 250.104 Article 300 Subarticle 300.11 Subarticle 300.21 Subarticle 300.22 Article 314 Article 324 Title Grounding and Bonding Buildings or Structures Supplied by Feeder(s) or Branch Circuit(s) Grounding Electrode System Use of Air Terminals Methods of Grounding and Bonding Conductor Connection to Electrodes Bonding of Piping Systems and Exposed Structural Steel Wiring Methods Securing and Supporting Spread of Fire or Products of Combustion Wiring in Ducts, Plenums, and Other Air-Handling Spaces Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures Flat Conductor Cable: Type FCC NOTE: The following articles from Chapter 3: Wiring Methods and Materials, primarily address pathway considerations. Article 342 Article 344 Article 348 Article 350 Article 352 Article 356 Article 358 Article 360 Article 362 Article 372 Intermediate Metal Conduit: Type IMC Rigid Metal Conduit: Type RMC Flexible Metal Conduit: Type FMC Liquidtight Flexible Metal Conduit: Type LFMC Rigid Nonmetallic Conduit: Type RNC Liquidtight Flexible Nonmetallic Conduit: Type LFNC Electrical Metallic Tubing: Type EMT Flexible Metallic Tubing: Type FMT Electrical Nonmetallic Tubing: Type ENT Cellular Concrete Floor Raceways 2004 BICSI 1-53 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 3: Codes, Standards, and Regulations National Fire Protection Association (NFPA), continued Table 1.4, continued National Electrical Code chapters, articles, and subarticles that impact ITS installation NEC Reference Article 374 Article 376 Article 378 Article 386 Article 388 Article 390 Article 392 Article 500 Article 605 Article 640 Article 645 Article 725 Article 760 Article 770 Article 780 Article 800 Article 810 Article 820 Article 830 Title Cellular Metal Floor Raceways Metal Wireways Nonmetallic Wireways Surface Metal Raceways Surface Nonmetallic Raceways Underfloor Raceways Cable Trays Hazardous (Classified) Locations, Classes I, II, and III, Divisions 1 and 2 Office Furnishings (Consisting of Lighting Accessories and Wired Partitions) Audio Signal Processing, Amplification, and Reproduction Equipment Information Technology Equipment Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits Fire Alarm Systems Optical Fiber Cables and Raceways Closed-Loop and Programmed Power Distribution Communications Circuits Radio and Television Equipment Community Antenna Television and Radio Distribution Systems Network-Powered Broadband Communications Systems NOTES: NEC Chapter 8: Communications Systems, stands separately and independently from other chapter and articles of the code, unless specifically referenced. Although some of the articles and subarticles listed in Table 1.4 are not referenced by chapter 8, the information in these articles and subarticles apply to all ITS. Not all countries use the NEC but rather refer to their own wiring regulations for electricity. ITS Installation Manual, 4th edition 1-54 2004 BICSI
Section 3: Codes, Standards, and Regulations Chapter 1: Background Information Standards Affecting Telecommunications in North America Introduction The purpose of a standard is to ensure a minimum level of performance. As defined in the 2002 TIA Engineering Manual (3rd Edition), a standard is a document that establishes engineering and technical requirements for processes, procedures, practices and methods that have been decreed by authority or adopted by consensus. Standards may be established for selection, application, and design criteria for material. Standards are established as a basis to quantify, compare, measure, or judge capacity, quantity, value, quality, performance, limits, and interoperability. A significant benefit of standards in the ITS industry is the aid to improved interoperability of components and systems by multiple manufacturers. Codes often reference numerous safety standards to ensure the minimum safety requirements of a given material or component. In the United States, the NEC requires that the cable placed in a space defined as a plenum or other air-handling space must be listed for that purpose. This listing is given to material that meets a specific test standard of requirements for: Flammability. Smoke generation. Smoke density. Test standards provide uniform rules for what is to be tested, how it is to be tested, and which results are acceptable. American National Standards Institute/Telecommunications Industry Association/Electronic Industries Alliance (ANSI/TIA/EIA) TIA and EIA are organizations that develop and submit standards to ANSI for approval and then publish and make available to the industry. TIA and EIA publish standards for the performance of manufacturing, installation, and electronic and telecommunications equipment and systems. Each standard covers a specific part of building and campus cabling. The standards address the required cable, hardware, equipment, design, testing, and installation practices. In addition, each standard lists related standards and other reference materials that deal with the same topics. Most of the standards include sections that define important terms, acronyms, and symbols. The following are ANSI/TIA/EIA standards that pertain to cabling in commercial buildings: TIA TSB-140 Additional Guidelines for Field-Testing Length, Loss and Polarity of Optical Fiber (2004) Additional guidelines for field-testing optical fiber cabling will provide guidance on Tier 1 and Tier 2 testing specifications and the use of the optical loss test set (OLTS) and the optical time domain reflectometer (OTDR) for premise cabling. 2004 BICSI 1-59 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 3: Codes, Standards, and Regulations American National Standards Institute/Telecommunications Industry Association/Electronic Industries Alliance (ANSI/TIA/EIA), continued TIA-526-7, OFSTP-7 Measurement of Optical Power Loss of Installed Singlemode Fiber Cable Plant (1998) (2002) (ANSI approval withdrawn July 2003) The intent of this test procedure is to ensure that meaningful data describing the optical loss performance of an installed single-mode cable plant can be obtained. It is not intended for component testing, nor does it define the elements of an installation that must be measured. The document that invokes this procedure establishes the requirements for installation, maintenance, repair, and conformance testing. TIA-526-14-A, OFSTP-14 Optical Power Loss Measurements of Installed Multimode Fiber Cable Plan, (1998) (R2003) (ANSI approval withdrawn August 2003) The intent of this document is to establish preferred measurement principles and practices to ensure that meaningful data describing the optical loss performance of an installed cable plant can be obtained. It is not intended for component testing, nor does it define the elements of an installation that must be measured. Establishment of requirements for installation, maintenance, repair, or conformance testing is left to the specifier of this test method. ANSI/TIA/EIA-455-78-B-2002, FOTP 78 IEC 60793 Optical Fibres Part 1-40: Measurement Methods and Test Procedures Attenuation ANSI/TIA/EIA-568-B.1-2001, Commercial Building Telecommunications Cabling Standard Part 1: General Requirements This standard partially replaces ANSI/TIA/EIA-568-A, published October 1995, with the addition of associated addenda, Telecommunications System Bulletins (TSBs), and interim standards (ISs). This standard specifies a generic telecommunications cabling system for commercial buildings that will support a multi-product, multi-vendor environment. ANSI/TIA/EIA-568-B.1-1-2001, Commercial Building Telecommunications Cabling Standard Part 1: General Requirements Addendum 1 Minimum 4-Pair UTP and 4-Pair ScTP Patch Cable Bend Radius Addendum 1 applies to the minimum 4-pair unshielded twisted-pair (UTP) and 4-pair screened twisted-pair (ScTP) patch cable bend radii. ANSI/TIA/EIA-568-B.1-2-2003, Commercial Building Telecommunications Cabling Standard Part 1: General Requirements Addendum 2 Grounding and Bonding Specifications for Screened Balanced Twisted-Pair Horizontal Cabling Addendum 2 specifies additional requirements for grounding (earthing) and bonding of installed screened balanced horizontal cables and connecting hardware used within a commercial building environment. ANSI/TIA/EIA-568-B.1-3-2003, Commercial Building Telecommunications Cabling Standard Part 1: General Requirements Addendum 3 Supportable Distances and Channel Attenuation for Optical Fiber Applications by Fiber Type Addendum 3 applies to the supportable distances and channel attenuation for optical fiber applications by fiber type. ITS Installation Manual, 4th edition 1-60 2004 BICSI
Section 5: Media Chapter 1: Background Information Media Overview Balanced twisted-pair cables are commonly used for information transport systems in buildings. Standards ISO/IEC 11801 Ed. 2:2002 and ANSI/TIA/EIA-568-B.2 cover the requirements for use of balanced twisted-pair cables in horizontal cabling. Horizontal cables shall consist of four balanced twisted-pairs of 24 AWG [0.51 mm (0.020 in)] thermoplastic insulated solid conductors enclosed by a thermoplastic jacket. There are two types of cable recognized and recommended for use in the horizontal cabling system. These cables are 4-pair 100-ohm UTP or ScTP. ITS cabling installers must be aware of the various types of media (cable) that are available for installation and maintenance. Each type and configuration has specific uses and defined methods that must be employed during installation. This section focuses on horizontal media, although, backbone cable is also identified. This document addresses various commonly used types of ITS cable. The major telecommunications cables are: Balanced twisted-pair cable: Category 3/class C Category 5e/class D Category 6/class E Enhanced shielded balanced twisted-pair (STP-A) cable. Coaxial cable: Thin Ethernet IEEE 802.3 Thick Ethernet IEEE 802.3 Series-11 backbone, Series-6 horizontal drop, and Series-59 patch cord RG-62 Optical fiber cable: Multimode (50/125 µm) Multimode (62.5/125 µm) Singlemode 2004 BICSI 1-103 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 5: Media Communications Wires and Cables and Communications Raceway Listing The NEC categorizes communications cables and pathways for interior installations based on their performance when exposed to fire. Table 1.9 summarizes Table 800.113 from the NEC. Table 1.9 Copper cable markings Cable Marking CMP CMR CMG CM CMX CMUC Type Communications plenum cable Communications riser cable Communications general purpose cable Communications general purpose cable Communications cable, limited use Undercarpet communications wire and cable Table 1.10 summarizes Table 800.154 of the NEC. Table 1.10 Copper cable substitutions Cable Type CMR CMG, CM CMX Permitted Substitutions CMP CMP, CMR CMP, CMR, CMG, CM ITS Installation Manual, 4th edition 1-104 2004 BICSI
Section 5: Media Chapter 1: Background Information Communications Wires and Cables and Communications Raceway Listing, continued Table 1.11 summarizes Table 770.113 of the NEC. Table 1.11 Optical fiber cable markings Cable Marking OFNP OFCP OFNR OFCR OFNG OFCG OFN OFC Type Nonconductive optical fiber plenum cable Conductive optical fiber plenum cable Nonconductive optical fiber riser cable Conductive optical fiber riser cable Nonconductive optical fiber general-purpose cable Conductive optical fiber general-purpose cable Nonconductive optical fiber general-purpose cable Conductive optical fiber general-purpose cable Table 1.12 summarizes Table 770.154 of the NEC. Table 1.12 Fiber cable substitutions Cable Type OFNP OFCP OFNR OFCR OFNG, OFN OFCG, OFC Permitted Substitutions None OFNP OFNP OFNP, OFCP, OFNR OFNP, OFNR OFNP, OFCP, OFNR, OFCR, OFNG, OFN 2004 BICSI 1-105 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 5: Media Balanced Twisted-Pair Cable Balanced twisted-pair cable has been used for many years for both voice and data cabling (see Figure 1.27). It has the following characteristics: Composed of pairs of wires twisted together Commonly available in various pair counts (2 2400 pairs) Normally not shielded below 600 pairs and has an overall aluminum-steel shield up to 2400 pairs Reduces electrical interference by conductors twisting Characteristic impedance of 100 ohms at 100 MHz and 600 ohms at 16 MHz Recommended conductor sizes 22 AWG [0.64 mm (0.025 in)] to 24 AWG [0.51 mm (0.020 in)] Figure 1.27 Typical balanced twisted-pair cable Cable jacket Cable jacket Drain wire Foil shield To improve information throughput, significant performance improvements have been made to UTP cable. In ANSI/TIA/EIA-568-B, specifications for several performance levels of UTP cable and associated connecting hardware were established as follows: Category 3/class C UTP cables and associated connecting hardware with transmission characteristics specified up to 16 MHz Category 4 UTP cables and associated connecting hardware with transmission characteristics specified up to 20 MHz Categories 5 and 5e/class D UTP cables and associated connecting hardware with transmission characteristics specified up to 100 MHz Category 6/class E cabling up to 250 MHz ITS Installation Manual, 4th edition 1-106 2004 BICSI
Section 8: Grounding, Bonding, and Protection Chapter 1: Background Information Grounding, Bonding and Protection Overview The electrical protection of ITS systems is an essential part of every installation. Proper grounding and bonding are necessary for both safety and performance. The following material from NEC has been reprinted with permission from the National Electrical Code NFPA 70-2005, Copyright 2004, National Fire Protection Association, Quincy, MA 02269: The following definitions are from the NEC, Article 100, Definitions: Ground is defined as, A conducting connection, whether intentional or accidental, between an electrical circuit or equipment and the earth, or to some conducting body that serves in place of the earth. Bonding is defined as, The permanent joining of metallic parts to form an electrically conductive path that ensures electrical continuity and the capacity to conduct safely any current likely to be imposed. Bonding conductors are not intended for carrying electrical load currents under normal conditions, but it must carry fault currents so that electrical protection (circuit breakers) would properly operate. As described earlier, another important safety application of bonding is limiting hazardous potential differences between different systems and equipment during lightning or power faults. This protects against arcing between different system (or equipment) grounds and protects personnel who may be exposed to both systems simultaneously. Grounding System Components The two areas of grounding that apply to commercial buildings are the: Grounding electrode system (also known as the earthing system). Equipment grounding system (also known as the electrical system s third wire safety ground). The grounding electrode system consists of a grounding: Field (earth). Electrode. Electrode conductor. The equipment grounding system consists of: Equipment grounding conductor(s). A main bonding jumper within the electrical system s main distribution panel. 2004 BICSI 1-177 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 8: Grounding, Bonding, and Protection Grounding System Components, continued In addition to the building grounding systems, a separate grounding system for telecommunications is defined in ANSI/J-STD-607-A. The electrical service entrance is outside the scope of this manual and is grounded, bonded, and protected in accordance with all applicable electrical codes. The telecommunications grounding and bonding infrastructure originates with a connection to the service equipment (power) ground and extends throughout the building. The five components comprising the telecommunications grounding system are the: Bonding conductor for telecommunications (BCT). Telecommunications main grounding busbar (TMGB). Telecommunications bonding backbone (TBB). Telecommunications grounding busbar (TGB). Grounding equalizer (GE). Additional components that may be included are: Lightning protector grounding system connections. Grounding electrodes. A grounding electrode conductor (GEC). There are several types of electrical protection systems within every building. Although the ITS cabling installer is not usually responsible for the other systems, it is not safe to work in a building without recognizing and understanding the purpose for each system. A clear understanding of these systems provides a basis for further training and working with other trades when necessary. This chapter describes the various electrical protection systems found in most of today s commercial buildings, such as: Lightning protection systems. Grounding electrode systems. Electrical grounding, bonding, and protection systems. Electrical power protection systems. Surge protection devices. ITS grounding, bonding and electrical systems. ITS circuit protectors. Safety Primary responsibilities of the cabling installer are safeguarding personnel, property, and equipment from foreign electrical voltages and currents. Foreign refers to electrical voltages or currents that are not normally carried by, or expected in, the ITS distribution systems. ITS Installation Manual, 4th edition 1-178 2004 BICSI
Section 8: Grounding, Bonding, and Protection Chapter 1: Background Information References A useful reference is the NEC Handbook, an expanded version of the code that has additional explanatory comments. NEC Chapter 8, Communications Systems, covers general requirements for grounding, bonding, and protecting low-voltage communications equipment. NEC Article 250, Grounding and Bonding covers electrical power circuits and low-voltage control and signaling systems. Even though NEC Chapter 8 is a stand-alone chapter, it refers the reader to Article 250 for specific grounding concerns. This manual is based on the 2005 edition of the NEC, although many local jurisdictions still require adherence to earlier editions. Always consult the AHJ to determine what edition of the NEC is being used in the jurisdiction. The Canadian Standards Association (CSA) publishes the Canadian Electrical Code (CE Code ), a CE Code Handbook, and a number of coordinated product test standards. These are comparable to the NEC (based on the same system grounding and protection methods) and have many similarities, but the two codes are not identical or interchangeable. ANSI/J-STD-607-A covers grounding and standard bonding requirements for telecommunications applications within commercial buildings. It is available as a stand-alone document or along with several other telecommunication standards, including the ANSI/TIA/EIA-568-B series, TIA-569-B, and ANSI/TIA/EIA-606-A documents as a set of Telecommunications Building Wiring Standards. ANSI/J-STD-607-A does not replace NEC requirements but provides additional standards for grounding and bonding. Note that it covers only grounding and bonding but relies on other standards and codes for many important protective measures. Electrical Exposure (ITS) NEC Section 800.90 covers safety code requirements for protectors. Additionally, it defines the exposed state as when a circuit is in such a position that, in case of failure of supports or insulation, contact with another conductor may result. The NEC requires a listed primary protector (at both ends) whenever outside plant cable may be exposed to lightning or accidental contact with power conductors operating at more than 300 V (see Figures 1.74 and 1.75). Exposure refers to an outdoor ITS cable s susceptibility to electrical power system faults, lightning, or other transient voltages. A cable is considered exposed if any branches or individual circuit is exposed. Lightning Exposure Lightning strikes can cause severe damage to ITS systems that have not been properly installed. Even with a properly installed grounding infrastructure, there are no guarantees that a direct lightning strike will not damage a system. The risk of damage is reduced when ITS has been properly bonded to the grounding infrastructure. 2004 BICSI 1-181 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 8: Grounding, Bonding, and Protection Lightning Exposure, continued A Lightning Exposure Guideline is included in the NEC Section 800.90(A) Fine Print Note (FPN) No. 2. It states, Interbuilding circuits are considered to have a lightning exposure unless one or more of the following conditions exist: (1) Circuits in large metropolitan areas where buildings are close together and sufficiently high to intercept lightning. (2) Interbuilding cable runs of 42 m (140 ft) or less, directly buried or in underground conduit, where a continuous metallic cable shield or a continuous metallic conduit containing the cable is bonded to each building grounding electrode system. (3) Areas having an average of five or fewer thunderstorm days per year and the earth resistivity of less than 100 ohmmeters. Such areas are found along the Pacific coast. If cable exposure is in question, consider it to be exposed and protect it accordingly. There are two additional exposure factors: Aerial cable usually has power cables routed above it that will intercept and divert direct lightning strikes. This can help but does not eliminate the need for protectors. Buried cable collects ground strikes within a distance determined by soil resistance (typically 1.83 6 m [6 20 ft]). High soil resistance intensifies this problem. Without the proper protection, a system could be receiving repeated ground strike surges without the evidence of damaged cable associated with an aerial strike. Lightning is so powerful and unpredictable that the best insurance against damage is a properly grounded and bonded system. Lightning may strike at any time with the potential effect of: A direct current surge, pulsating between 100 khz and 2 MHz. 10 million V or greater. An average 40,000 amperes that can peak as high as 270,000 amperes. Temperatures in excess of 27 760 ºC (50,000 ºF). Grounding and earthing systems must be designed and installed in such a way that they can safely carry the unwanted voltages to the earth. Electrical Exposure (Building Structure) NFPA 780, Standard for the Installation of Lightning Protection Systems, covers lightning protection systems for buildings and defines the exposed state as anything above ground and outside a zone of protection (an area under or nearly under a lightning protection system). This does not include communications cable. A zone of protection is shown in Figure 1.74. These lightning protection systems intercept and ground lightning strikes to the building. They are generally recognized by the metal spikes on top of the building. ITS Installation Manual, 4th edition 1-182 2004 BICSI
Section 8: Grounding, Bonding, and Protection Chapter 1: Background Information Lightning Protection System, continued If the ITS ground relies on the electrical service grounding electrode system, the more common grounding practices will apply. ITS grounding practices will be discussed later in the chapter. NEC Section 800.53 and NFPA 780 require that, where practicable, a separation of at least 1.8 m (6 ft) should be maintained between communications wires and cables on buildings and lightning conductors. This separation will help prevent hazardous voltages from being induced or coupled over to the ITS cables during a lightning strike. This separation requirement does not apply to buildings that use building steel as the lightning down conductor. Electrical Power Systems An electrical power system provides the electrical infrastructure necessary to distribute electricity throughout the building. All the appliances, lighting circuits, and equipment are fed through the network of branch circuits. The heart of the electrical power system is its being referenced or grounded to the earth. In most ITS grounding systems, the ground reference is established by bonding the bonding conductor for ITS to the electrical service ground at the electrical service equipment (see Figure 1.77). Figure 1.77 Typical (small) electrical power system Detail Receptacle Ground conductor Detail Branch circuit bonded conduit Building structural steel Main electrical service panel Overcurrent protection Grounding electrode system Metal water pipe Footing ground 2004 BICSI 1-185 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 8: Grounding, Bonding, and Protection Electrical Bonding and Grounding Throughout NEC Article 250, electrical bonding and grounding are described as metallic panels and raceways that are bonded to an equipment grounding conductor and are then bonded to the grounded electrical service neutral at the service equipment. An equipment grounding conductor shall be routed with the power and neutral conductors. Electrical systems and metallic apparatus are bonded and grounded to limit hazardous voltages due to: Electrical power faults. Lightning. Other electrical transients. This facilitates overcurrent protection operation in the case of electrical power faults that would otherwise place hazardous voltages at dangerous points. Inadvertent shorting of the power conductor to the equipment ground, or to other bonded metal or conductors, will cause a circuit breaker (overcurrent protection) to operate and disconnect power. These systems are not usually the responsibility of the cabling installer, but they should be recognized and understood, since most sites have power protection designed specifically for ITS equipment. Electrical Power Protection Electrical power protection is covered throughout NEC Chapter 2, Wiring and Protection, which includes electrical bonding and grounding requirements. The following are required for complete electrical protection: Surge arresters Divert surge current coming in on utility power conductors. Service disconnecting means Main service breaker provides a method for overall power shutdown based on emergency or maintenance. Overcurrent protection Circuit breakers open individual power circuits, if the current reaches a predetermined unsafe level. NOTE: Other components that improve the overall quality of electrical power include power line conditioners, UPSs, and power backup systems. These systems are not usually the responsibility of the cabling installer, but should be recognized and understood, since most sites have power protection designed specifically for ITS equipment. Grounding Electrode System As defined in NEC Article 100, Definitions, a grounding electrode is a device that establishes an electrical connection to earth. A grounding electrode system is a network of electrically connected ground electrodes used to achieve an improved low resistance to the earth and, in many cases, to aid equalization of potentials around a building. ITS Installation Manual, 4th edition 1-186 2004 BICSI
Section 8: Grounding, Bonding, and Protection Chapter 1: Background Information Grounding Electrode System, continued All ground electrodes can be divided into two groups: Underground piping systems, metal building framework, well casings, steel pilings, and other underground metal structures installed for purposes other than grounding. Electrodes specifically designed for grounding purposes (i.e., driven and buried ground rod, ground rod system, buried ground rings and grids, metal plates, chemically enhanced ground rods and systems). A properly functioning ground is essential to electrical protection because it: Conducts any excess electrical energy to the earth without causing hazardous arcing, heating, or explosion during lightning. Establishes a common potential reference. NEC Section 250.58 requires a common grounding electrode system for different electrical systems within a building. Where two or more electrodes are effectively bonded together, they shall be considered as a single grounding electrode system. NEC Section 250.94 requires an intersystem bonding connection accessible at the electrical service equipment. This connection is a prime choice for establishing an ITS ground. (See Using the Electrical Service Ground in this section.) In a distribution system of 600 V or less, the objective is to achieve the lowest possible grounding electrode resistance. This applies to the ITS installation, since the electrical grounding electrodes are usually shared by the ITS grounding infrastructure. The use of continuous metallic underground water pipes, as well as metal structural frames of buildings, typically provides excellent ground resistance not exceeding 3 ohms. When a single electrode is installed, NEC 250.56 states that a single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any of the types specified by 250.52(A)(2) through (A)(7). Where multiple rod, pipe, or plate electrodes are installed to meet the requirements of this section, they shall not be less than 1.8 m (6 ft) apart. When a single electrode fails to meet the 25 ohm requirement, the NEC requires that a single additional electrode be installed. NEC does not require the installation to be retested or to meet the 25 ohm requirement. The reason is that the installation is no longer a single electrode but is now defined as a system. NEC 250.58 states, Two or more grounding electrodes that are effectively bonded together shall be considered as a single grounding electrode system in this sense. NEC Article 250 does not offer a requirement for the maximum resistance to the earth when a grounding electrode system is installed. It is commonly assumed in error that the grounding electrode system will have a resistance to ground of 25 ohms or less. (See IEEE 1100, Recommended Practice for Powering and Grounding Electronic Equipment.) Many smaller installations have two ground rods driven into the earth, 1.8 m (6 ft) apart and, therefore, have met the requirements of a system. Since most local authorities do not require the actual resistance values of systems to be verified, equipment and personnel may be placed in jeopardy. 2004 BICSI 1-187 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 8: Grounding, Bonding, and Protection Grounding Electrode System, continued On the flip side, installers should keep in mind that NEC s primary focus is the safety of people and property (buildings), and that thus its requirements do not specifically address the protection of today s sensitive electronics. If the grounding requirements set forth by the equipment manufacturer are not met, the warranty may not be honored. Electronics often requires grounding connections to the earth of less than 10 ohms, with some as little as 1 ohm. Understanding how to install and test a grounding electrode system is a crucial task for a cabling installer. Installing a Grounding Electrode The resistance of the grounding electrode system should be as low as possible (25 ohms or less) and measured annually with an earth megger. NOTE: 25 ohms or less ground is an NEC safety requirement and has nothing to do with system performance. Some system performance requirements can only be met by less than a 1 ohm impedance to ground. The NEC Handbook, Section 250.52, provides a few examples for the installation of a grounding electrode or electrode system. The installation of a telecommunications grounding electrode is allowed if: There is no electrical service ground (e.g., a telephone and its cable protectors are installed in a barn that has no electrical service). Additional grounding is needed (NEC 250.54, 62, 64, and 118). If so, the installed electrode must be bonded to the existing ground electrode system. According to NEC 800.100(B)(2)(2), buildings or structures without a grounding means (no electrical service, such as a barn or possibly a warehouse) may have an electrode installed for the purpose of bonding the ITS circuit protectors to the earth. This rod may be sized not less than 12.7 mm (0.5 in) diameter and only 1.5 m (5 ft) long. A rod of this size is not allowed for any other purpose than bonding an ITS protector terminal. The cabling installer should avoid using 1.5 m (5 ft) electrodes. After a 1.5 m (5 ft) rod has been installed, it could be assumed that it was driven 2.4 m (8 ft) into the earth. An electrician installing a new service may attempt using a smaller rod as a means of grounding. This would not be a safe installation, since NEC Article 250 requirements would not be met. BICSI does not recommend that 1.5 m (5 ft) rods be used. Instead, an electrode sized in accordance with NEC 250.52(A)(5), should be installed. This will provide for a safe installation and for any future electrical system additions. BICSI recommends a: Minimum 2.4 m (8 ft) by 16 mm (5/8 in) copper-clad ground rod. 6 AWG [4.1 mm (0.16 in)] solid grounding conductor. NOTE: If the connection to the grounding conductor is made below grade, use an exothermic weld. Exothermic weld is discussed in detail later in this chapter. ITS Installation Manual, 4th edition 1-188 2004 BICSI
Section 8: Grounding, Bonding, and Protection Chapter 1: Background Information Installing a Grounding Electrode, continued Other alternative electrodes include ground rings and plates. The ground ring electrode consists of: A non-insulated conductor that is buried in the shape of a ring according to NEC 250.52(A)(4). Conductors that are buried at a minimum depth of 762 mm (30 in). A minimum of 6 m (20 ft) in length. A minimum of 2 AWG [6.5 mm (0.26 in)]. The plate electrode consists of: Iron or steel plates that are minimum 6.3 mm (0.25 in) thick. Nonferrous metal plates that are minimum 1.6 mm (0.063 in) thick. Exposed surface area of at least 0.186 m 2 (2 ft 2 ). The following conditions must be strictly observed: Any installed grounding electrode must be at least 1.83 m (6 ft) away from other existing electrodes. Electrodes or down conductors that are part of a lightning protection system are not allowed for use as an electrode for this purpose. Regardless of what alternative is selected for installing a ground rod, all other electrical system grounds, structural building steel, and metallic piping systems must be bonded together. This is required of the electrical service and is usually already accomplished, but it should be verified. Gas pipes, steam pipes, or hot water pipes are not allowed as a grounding electrode, but still require bonding to other electrodes. Physical Protection The electrode should be installed so that the top of the electrode is at or below ground level. If the top of the electrode is above ground level, the electrode, GEC, and their bond should be protected from damage, as per NEC Section 250.10. If the protection consists of a metallic conduit or raceway, both ends must be bonded to the grounding conductor or the same terminal or electrode to which the grounding conductor is connected, as per NEC Section 800.100(A)(6). The bonding of the conductor to both ends of the metallic conduit or raceway will provide equalization between the conductor and the metallic pathway. If not properly bonded together, an inductive choke may be created, which, in the event of a fault, could hinder the flow of current. Earth Resistance Generally, earth resistance is the resistance of soil to the passage of electrical current. The earth is a relatively poor conductor of electricity compared to normal conductors (e.g., copper wire). However, if the path for current is large enough, the resistance can be quite low and earth can be a good conductor. 2004 BICSI 1-189 ITS Installation Manual, 4th edition
Chapter 1: Background Information Section 8: Grounding, Bonding, and Protection Earth Resistance, continued Earth resistivity is far from a constant, and has a predictable value ranging generally from 500 to 200,000 ohm-cm. Some factors that can affect the resistance value of the surrounding earth include: Moisture content of the soil. Quantity of electrolytes (a conducting medium that allows the flow of current). Type of electrolytes. Adjacent conductors. Temperature. Electrode depth. Electrode diameter. Electrode(s) spacing distance. Earth Resistance Tester or Earth Megger Formulas used for computing the earth resistivity are complicated, and the earth resistivity is neither uniform nor constant; therefore, a simple and direct method of measuring the earth resistance is needed. The instrument used is an earth megger tester. The earth megger tester is a self-contained portable instrument that is reliable and easy to use. It can measure the resistance of the earth alone or the resistance of an installed electrode system and its surrounding earth. An earth resistance tester is known as an earth megger but should not be confused with an electrician s megohmmeter (commonly called a megger). The electrician s megger is used to test the insulation of power conductors and cannot be used to measure the earth resistivity. An earth electrode system that provides a low ground resistance is not easy to obtain. However, with experience, a cabling installer can learn to set up a reliable system and check the resistance value with reasonable accuracy. The principles and methods of earth resistance testing apply to systems that require low resistance ground connections and include: Lightning arrester installations. Power generating stations. Electrical distribution systems. Industrial plants. ITS installations. Several companies manufacture earth megger instruments for the testing of earth resistance. These instruments incorporate: A voltage source. An ohmmeter. Switches to change the meter s resistance range. Small test rods or electrodes. ITS Installation Manual, 4th edition 1-190 2004 BICSI
Section 8: Grounding, Bonding, and Protection Chapter 1: Background Information Improving Earth Resistance, continued Hollow rods are similar to a hollow drainage pipe that has small holes drilled along its length to allow water to leach into the surrounding soil. These rods are usually 64 mm (2.5 in) wide and are available in varying lengths. The rod is filled with electrolyte-enhancing chemicals and buried either vertically or horizontally in the soil. Most hollow rods require that one end remain accessible for future replenishment of chemicals. These rods offer a greater area of treatment due to their ability to leach more chemicals into the surrounding earth. NOTE: These chemicals may be corrosive and may cause the ground rods to have a shortened life span when compared to that of a standard ground rod. Chemically treated rods are often used: Where the location does not allow vertical placement of a driven ground rod. Where the soil resistivity is extremely high. In conjunction with standard ground rods to form a grounding network. Soil Treatment Chemical treatment of the soil improves earth-electrode resistance when longer rods cannot be driven into the soil because of rock beds. A soil that has been chemically treated provides a more uniform ground through seasonal changes. Some of the disadvantages are: Chemicals concentrated around electrodes may cause corrosion and shorten the life of an installed electrode system. Chemicals leach through the soil and dissipate. Scheduled replenishment may be required every few years or as often as every three months. Dissipation is dependent on weather, rainfall, and, even, sprinkler systems. Some areas of the country prohibit the use of chemical treatment due to the possible contamination of the water table and the local drinking water. An alternative to chemical treatment is the use of a noncorrosive, but conductive, compound between the electrode and the soil. A hole in the soil is created around the electrode; bags of the granular compound are premixed with water to create a cement-like mortar, which is then poured into the hole. It is covered with topsoil. When water is not readily available, some products may be installed in a dry powder form. Dry installations will not provide the maximum ground resistance reduction until moisture leaches into the soil and cures the compound. Unlike chemical treatment, this is considered a permanent treatment, since the compound will not leach away when exposed to moisture. Premixing is recommended because it ensures a consistent installation and can be readily tested after the curing time. Dry installations may take months to reach their full conductive potential. 2004 BICSI 1-205 ITS Installation Manual, 4th edition