1 Scope
NOTE This specification covers the materials, configuration, installation, and field verification of the telecommunications bonding and grounding (earthing) system within customer-premises buildings, in accordance with ANSI/TIA-607-E. (1.1)
1.2 The telecommunications bonding and grounding system shall establish a single, low-impedance path interconnecting telecommunications equipment, racks, cabinets, cable shields, pathway metallic components, and protectors to the building grounding electrode system, so that fault current is cleared, surge energy is conducted to earth, and electronic equipment operates without ground-loop interference.
NOTE The telecommunications system shall be bonded to the building grounding electrode system at exactly one point — the Primary Bonding Busbar — so that the telecommunications and electrical systems share a common reference to earth and no objectionable potential difference can develop between them under normal or fault conditions. (1.3)
NOTE The building grounding electrode system itself is covered by
Grounding And Bonding; the scope of this standard begins at the bonding conductor from the building grounding electrode system to the Primary Bonding Busbar and extends to every telecommunications space, rack, and cabinet on the project.
(1.4) NOTE This standard does not cover lightning protection systems, which are designed and installed under NFPA 780 and are bonded to the building grounding electrode system as a separate scope. (1.5)
NOTE This standard does not cover data center grounding at the higher-tier levels of ANSI/TIA-942 or BICSI 002, which impose additional grid, mesh, and signal-reference requirements beyond TIA-607. (1.6)
1.7 Where the project includes a data center or computer room classified to TIA-942 Rated 3 or Rated 4, the more stringent requirements of TIA-942 shall apply in those spaces; this standard establishes the minimum.
1.8 Coordination with Grounding And Bonding is required at the point of connection to the building grounding electrode system. 1.10 Coordination with Conductors And Cables is required for the supply branch circuits serving telecommunications equipment. 1.11 Coordination with Low Voltage Switchgear is required where telecommunications equipment is bonded to dedicated ground bars in service or distribution equipment rooms. 2 Referenced Standards
2.1 Equipment, materials, and installation shall comply with the latest adopted edition of the following standards and codes.
| Standard |
Title |
| ANSI/TIA-607-E |
Generic Telecommunications Bonding and Grounding (Earthing) for Customer Premises |
| ANSI/TIA-568.0-E |
Generic Telecommunications Cabling for Customer Premises |
| ANSI/TIA-568.1-E |
Commercial Building Telecommunications Cabling Standard |
| ANSI/TIA-568.2-E |
Balanced Twisted-Pair Telecommunications Cabling and Components Standard |
| ANSI/TIA-568.3-E |
Optical Fiber Cabling and Components Standard |
| ANSI/TIA-569-E |
Telecommunications Pathways and Spaces |
| ANSI/TIA-942-C |
Telecommunications Infrastructure Standard for Data Centers (informational, higher-tier reference) |
| BICSI TDMM, 14th edition |
Telecommunications Distribution Methods Manual |
| BICSI 002 |
Data Center Design and Implementation Best Practices (informational) |
| NFPA 70 |
National Electrical Code (Article 250 — Grounding and Bonding; Article 800 — Communications Circuits; Article 770 — Optical Fiber Cables; Article 805 — Communications; Article 840 — Premises-Powered Broadband Communications Systems) |
| NFPA 70E |
Standard for Electrical Safety in the Workplace |
| NFPA 780 |
Standard for the Installation of Lightning Protection Systems |
| UL 467 |
Grounding and Bonding Equipment |
| UL 497 |
Protectors for Paired-Conductor Communications Circuits |
| UL 497A |
Secondary Protectors for Communications Circuits |
| UL 497B |
Protectors for Data Communications and Fire-Alarm Circuits |
| UL 497C |
Protectors for Coaxial Communications Circuits |
| IEEE 1100 |
Recommended Practice for Powering and Grounding Electronic Equipment (Emerald Book) |
| IEEE 142 |
Recommended Practice for Grounding of Industrial and Commercial Power Systems (Green Book) |
| ASTM B187 |
Standard Specification for Copper, Bus Bar, Rod, and Shapes and General Purpose Rod, Bar, and Shapes |
| ASTM B3 |
Standard Specification for Soft or Annealed Copper Wire |
| ASTM B8 |
Standard Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft |
2.2 Where the contract documents, the adopted building code, or a referenced standard conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
3 Submittals
3.1 Action Submittals
3.1.1 Contractor shall submit the following for the Engineer's review prior to procurement and installation.
3.1.2 No portion of the telecommunications bonding and grounding system shall be installed until the corresponding submittals are reviewed and returned.
- Product data for the Primary Bonding Busbar (PBB), each Secondary Bonding Busbar (SBB), Rack Bonding Busbars (RBB), Telecommunications Equipment Bonding Conductor (TEBC) components, lugs, splice connectors, listing marks, and labeling
- Product data for telecommunications protectors at outside-plant entrance points and for any inter-building circuits, including UL 497, UL 497A, UL 497B, or UL 497C listing as applicable to circuit type
- A telecommunications bonding and grounding riser diagram showing the building grounding electrode system connection point, the PBB location, the routing of the Telecommunications Bonding Backbone (TBB), each SBB and its serving telecommunications space, all TEBC runs, and all rack and cabinet bonding points
- Conductor sizing calculations for the bonding conductor to the building grounding electrode system, the TBB, the Grounding Equalizer (GE) where used, the TEBC, and each rack bonding jumper, including the route length basis for TBB sizing per TIA-607-E
- Coordination drawings showing the location of the PBB in the entrance facility or main equipment room, the SBB in each telecommunications room, and the relationship of the bonding network to the equipment racks, cable trays, ladder rack, and pathways
- A proposed field verification plan describing continuity, dc resistance, and bonding integrity tests with acceptance criteria
☐ Product data for PBB, SBB, RBB, and bonding hardware
☐ Product data for telecommunications protectors (UL 497 / 497A / 497B / 497C)
☑ Telecommunications bonding and grounding riser diagram
☐ Conductor sizing calculations for TBB, GE, TEBC, and rack jumpers
☐ Coordination drawings (PBB, SBB, racks, pathways)
☐ Field verification plan and acceptance criteria
3.2 Closeout Submittals
3.2.1 Contractor shall provide the following at substantial completion before the telecommunications bonding and grounding system is accepted.
- Field test reports for all continuity and dc resistance testing, including measured values, instrument identification and calibration date, ambient conditions, acceptance criteria, and pass/fail determination, signed by the testing technician
- As-built telecommunications bonding and grounding riser diagram reflecting the installed routing, busbar locations, and connection points
- Operation and maintenance data describing periodic inspection and re-test intervals
- Warranty documentation for products carrying a manufacturer warranty
☑ Field test reports for continuity and dc resistance testing
☑ As-built telecommunications bonding and grounding riser diagram
☑ Operation and maintenance data with inspection and re-test intervals
☑ Warranty documentation
4 Quality Assurance
4.1 Installer Qualifications
4.1.1 The telecommunications bonding and grounding system shall be installed by technicians experienced in TIA-607 work and supervised by a licensed low-voltage or electrical contractor.
4.1.2 Personnel making compression bonding connections shall be trained by the connector manufacturer in the specific die set and tool combination being used.
4.1.3 Where the project requires a BICSI-credentialed designer or installer (RCDD, ITS Installer 2, Technician), the credentials shall be identified in the submittal.
4.2 Listing and Labeling
4.2.1 All bonding and grounding components — busbars, lugs, connectors, conductors, and protectors — shall be listed and labeled by a Nationally Recognized Testing Laboratory.
4.2.2 Bonding hardware shall be listed to UL 467.
4.2.3 Telecommunications protectors shall be listed to UL 497, UL 497A, UL 497B, or UL 497C as appropriate to the circuit type and protector function.
4.2.4 Unlisted bonding components and unlisted protectors shall not be installed.
4.3 Single-Point Connection to the Building Grounding Electrode System
4.3.1 The telecommunications bonding and grounding system shall be connected to the building grounding electrode system at exactly one point: the Primary Bonding Busbar.
4.3.2 The PBB shall be bonded to the building grounding electrode system by the bonding conductor to the building grounding electrode system (BCT).
4.3.3 Multiple bonding paths from telecommunications busbars to the building grounding electrode system shall not be installed.
NOTE Multiple paths create ground loops that defeat the single-point reference intended by TIA-607-E and produce circulating noise current on telecommunications cable shields. (4.3.4)
4.4 Regulatory Inspection
4.4.1 The telecommunications bonding and grounding system shall be available for inspection by the Authority Having Jurisdiction before being concealed by ceiling, finishes, or equipment.
4.4.2 The Contractor shall coordinate inspection timing for the bonding conductor to the building grounding electrode system, the PBB, the TBB risers, and each SBB.
5 Environmental and Service Conditions
5.1 Indoor Telecommunications Spaces
5.1.1 The PBB, SBB, and RBB are intended for installation in conditioned interior telecommunications spaces — entrance facilities, equipment rooms, telecommunications rooms, and computer rooms — that satisfy the environmental conditions of ANSI/TIA-569-E.
5.1.2 Telecommunications busbars and bonding hardware shall not be installed in wet, damp, or corrosive environments without supplemental enclosures listed for the environment.
5.2 Coordination with Power Equipment
5.2.1 The PBB shall be located in the entrance facility or the main equipment room and shall be physically and electrically accessible from the building service grounding point.
5.2.2 Where practical, the PBB shall be located close to the service entrance and the main electrical room to minimize the length of the bonding conductor to the building grounding electrode system.
5.2.3 Coordination with Grounding And Bonding is required to identify the connection point and the BCT routing. 5.3 Separation from Sources of Interference
5.3.1 Telecommunications bonding conductors shall be routed to minimize coupling with sources of electromagnetic interference.
5.3.2 Bonding conductors should be installed away from variable-frequency drive output cables, switchmode power supply equipment, and unshielded high-current bus runs.
NOTE Even though the bonding conductor itself is not a signal path, close coupling can induce circulating current that propagates onto cable shields bonded to the same busbar. (5.3.3)
6 Bonding Network Architecture
NOTE The telecommunications bonding network described by ANSI/TIA-607-E is a tree-topology, single-point-of-connection system rooted at the building grounding electrode system. (6.1)
● Tree topology per TIA-607-E (PBB root, SBB branches, TEBC leaves)
○ Tree topology with optional Grounding Equalizer (GE) between SBBs on the same floor
NOTE The Primary Bonding Busbar is the root of the tree; the Telecommunications Bonding Backbone connects the PBB to each Secondary Bonding Busbar serving a telecommunications space on a different floor or remote area of the building, and within each space served by an SBB the equipment racks, cabinets, cable trays, and metallic pathways are bonded back to the SBB by Telecommunications Equipment Bonding Conductors and Rack Bonding Jumpers. (6.2)
6.3 The bonding network shall be installed as a hierarchical tree without loops.
6.4 Grounding Equalizer
● Not provided
○ Provided where required to interconnect SBBs on the same floor
6.4.1 Where two or more SBBs are located on the same floor and the floor contains telecommunications equipment with high-speed signaling that requires a low impedance between SBBs, a Grounding Equalizer (GE) conductor is permitted by TIA-607-E to interconnect those SBBs at the same floor level.
6.4.2 The GE shall be sized the same as the TBB it supplements.
6.4.3 The GE shall connect SBBs only on the same floor and shall not create a loop with the TBB.
NOTE The GE is a permitted local supplement to reduce SBB-to-SBB impedance, not a parallel return path to the PBB. (6.4.4)
6.4.5 Where the project does not include high-speed equipment that requires the GE, the GE shall be omitted.
7 Primary Bonding Busbar
NOTE The Primary Bonding Busbar is the central bonding point of the telecommunications bonding network. (7.1)
NOTE It is the single point at which the telecommunications system is bonded to the building grounding electrode system, and it is the point from which the Telecommunications Bonding Backbone originates. (7.2)
7.3 Location
Entrance facility (telecommunications service entrance room)
Main equipment room
Main electrical room (where consolidated with electrical grounding)
7.3.1 The PBB shall be located in the entrance facility or in the main telecommunications equipment room, positioned for accessibility and proximity to the bonding conductor to the building grounding electrode system.
7.3.2 The PBB shall be wall-mounted on an insulating standoff that holds the busbar away from the supporting structure, so that the busbar is electrically isolated except through its intended bonding connections.
7.4 PBB Material and Construction
● Solid copper, electro-tin plated
○ Solid copper, bare
6 mm × 100 mm × variable length (1/4 in × 4 in × length per TIA-607-E)
6 mm × 100 mm × 300 mm minimum (standard small PBB)
6 mm × 100 mm × 600 mm (extended PBB for large equipment rooms)
7.4.1 The PBB shall be solid copper bus bar conforming to ASTM B187, predrilled for two-hole compression lug terminations on standard NEMA hole spacing.
NOTE Electro-tin plating is recommended to reduce contact-surface oxidation and to ease future terminations; the marginal cost is low and tin plating extends the working life of the bonding connections. (7.4.2)
7.4.3 Bare copper is acceptable in dry, climate-controlled telecommunications spaces.
7.4.4 The PBB shall be not less than 6 mm thick by 100 mm wide (1/4 in. by 4 in.), with length determined by the number of bonding terminations to be made.
7.4.5 The Contractor shall size the busbar length so that no terminations are stacked on a single bolt and so that future terminations can be added without rework.
7.4.6 The PBB shall be predrilled by the manufacturer for two-hole NEMA-pattern terminations; field drilling of additional holes is permitted if the manufacturer's pattern is maintained and burrs are removed.
7.5 PBB Mounting
7.5.1 The PBB shall be mounted on insulating standoffs with a clearance of at least 50 mm (2 in.) between the back face of the busbar and the supporting wall surface.
7.5.2 The standoffs and mounting hardware shall be of a material that does not create a galvanic couple with the copper busbar.
7.5.3 The PBB shall be mounted at a height that allows comfortable working access to all terminations, typically 1.8 m to 2.4 m (6 ft to 8 ft) above finished floor, and shall not be located behind future equipment.
7.6 Bonding Conductor to the Building Grounding Electrode System
6 AWG
4 AWG
2 AWG
1/0 AWG
2/0 AWG
3/0 AWG
750 kcmil maximum per TIA-607-E
Per drawings (deferred by default)
7.6.1 The PBB shall be bonded to the building grounding electrode system by a copper bonding conductor sized per TIA-607-E based on the length of the conductor between the PBB and the connection point in the building grounding electrode system.
7.6.2 The bonding conductor shall be installed in as direct and short a routing as practical, with no splices in the run, and shall be supported and protected against physical damage per Grounding And Bonding. 7.6.3 The connection at the building end shall be made by exothermic welding or by a listed irreversible compression connector.
7.6.4 Coordination with the electrical Contractor responsible for the building grounding electrode system is required to confirm the connection point and timing.
7.6.5 The bonding conductor shall be sized from the TIA-607-E length-based sizing schedule, in which the conductor size grows with the route length to keep the dc resistance and ac impedance of the bonding path within acceptable limits.
7.6.6 The Contractor shall not undersize the conductor based on a shorter ad-hoc routing; the installed route length governs.
8 Telecommunications Bonding Backbone
NOTE The Telecommunications Bonding Backbone is the conductor that extends from the PBB to each Secondary Bonding Busbar serving a telecommunications space. (8.1)
NOTE The TBB establishes the bonding reference at every SBB and is the primary mechanism by which telecommunications spaces share a common ground reference with the PBB. (8.2)
8.3 TBB Material and Type
● Insulated, stranded copper conductor
○ Bare, stranded copper conductor (where physical protection is provided)
8.3.1 The TBB shall be a copper conductor conforming to ASTM B3 and ASTM B8.
NOTE Insulated, stranded copper with green-colored insulation, or green with yellow stripe, is the standard construction for the TBB and provides physical protection against incidental contact and corrosion. (8.3.2)
8.3.3 Bare copper is permitted within secured telecommunications spaces where the conductor is supported on insulators and protected from physical damage.
8.4 TBB Sizing
6 AWG (minimum, runs up to approximately 4 m)
4 AWG
3 AWG
2 AWG
1/0 AWG
2/0 AWG
3/0 AWG
750 kcmil (maximum per TIA-607-E)
Per drawings (deferred by default)
8.4.1 The TBB shall be sized per ANSI/TIA-607-E based on the length of the longest TBB run between the PBB and the most distant SBB.
8.4.2 The TBB conductor shall be not smaller than 6 AWG copper, with the size increasing with length per the TIA-607-E sizing table.
8.4.3 The TBB shall be sized for the full route length, including vertical risers, horizontal pathway, and slack at busbar terminations; the Contractor shall not interpolate to a shorter conductor based on hypothetical routing.
8.4.4 A TBB shorter than the table's minimum length threshold shall still use 6 AWG; the minimum is a floor, not a function of length.
8.4.5 The TBB shall be continuous from the PBB to each SBB without splices, except where splices are made by exothermic welding or by listed irreversible compression connectors.
8.4.6 Bolted, screwed, or other removable splices in the TBB are not permitted.
8.5 TBB Routing
8.5.1 The TBB shall be routed as direct and short as practical between the PBB and each SBB, generally following the same backbone pathway as the telecommunications cabling.
8.5.2 Routing shall avoid sharp bends, areas of high electromagnetic interference, and pathways used by lightning down-conductors.
8.5.3 The TBB shall be supported per Raceways And Conduit and shall be protected against physical damage where exposed. 8.6 TBB Terminations
● Listed two-hole compression lug, NEMA hole pattern
○ Listed two-hole bolted mechanical lug (where compression is impractical)
8.6.1 The TBB shall be terminated at both the PBB and each SBB with listed two-hole compression lugs sized for the conductor and the busbar hole pattern.
8.6.2 Single-hole lugs shall not be used at the PBB or SBB; the two-hole configuration prevents rotation under fault current or seismic event.
8.6.3 Compression lugs shall be installed with the manufacturer's specified tool and die and shall be inspected for full crimp coverage and proper die imprint.
8.7 Multiple TBBs
8.7.1 Where the building is large enough or has telecommunications spaces in arrangements that would require an excessively long TBB run, more than one TBB may originate at the PBB.
8.7.2 Each TBB shall be sized for its own longest run.
8.7.3 The TBBs shall not be interconnected at points downstream of the PBB except through the optional Grounding Equalizer at the same floor.
NOTE Interconnecting TBBs downstream of the PBB other than through the Grounding Equalizer creates a parallel path and breaks the single-point bonding topology. (8.7.4)
9 Secondary Bonding Busbar
NOTE The SBB is the local termination point for the TBB and the local origin for the TEBCs that bond racks, cabinets, and pathways in that space. (9.1)
9.2 A Secondary Bonding Busbar shall be provided in each telecommunications room, equipment room, and entrance facility on each floor served by the telecommunications backbone.
9.3 SBB Material and Construction
● Solid copper, electro-tin plated
○ Solid copper, bare
6 mm × 50 mm × variable length (1/4 in × 2 in × length per TIA-607-E)
6 mm × 50 mm × 300 mm (standard SBB)
6 mm × 50 mm × 600 mm (large SBB for equipment-dense rooms)
9.3.1 The SBB shall be solid copper bus bar conforming to ASTM B187, predrilled for two-hole compression lug terminations on standard NEMA hole spacing.
NOTE Electro-tin plating is recommended for the same reasons as the PBB. (9.3.2)
9.3.3 The SBB shall be not less than 6 mm thick by 50 mm wide (1/4 in. by 2 in.), with length sized for the number of bonding terminations to be made plus 25 percent reserve capacity for future additions.
9.4 SBB Mounting
9.4.1 The SBB shall be mounted on insulating standoffs with a clearance of at least 50 mm (2 in.) from the supporting wall, in the same manner as the PBB.
9.4.2 The SBB shall be located in the telecommunications space at a position that provides direct, short TEBC routing to the equipment racks and cabinets in that space.
9.4.3 Where the room contains multiple rack rows or cable tray runs, the SBB should be located near the entry point of the TBB and in line with the bonding paths to the equipment, not relegated to an inaccessible corner.
9.5 SBB Connections
9.5.1 The SBB shall be bonded to the TBB by a listed two-hole compression lug.
9.5.2 Each TEBC and each individual equipment bonding conductor terminating at the SBB shall be made with a listed two-hole compression lug.
9.5.3 Single-hole lugs and crimped ring terminals shall not be used at the SBB.
10 Telecommunications Equipment Bonding Conductor
NOTE The Telecommunications Equipment Bonding Conductor extends from the SBB to bond telecommunications equipment racks, cabinets, ladder rack, cable tray, and other metallic pathway components within the telecommunications space. (10.1)
10.2 TEBC Construction
● Insulated, stranded copper with green or green-with-yellow-stripe insulation
○ Bare, stranded copper (within secured telecommunications spaces, on insulators)
10.3 TEBC Sizing
6 AWG (minimum per TIA-607-E)
4 AWG
2 AWG
1/0 AWG
10.3.1 The TEBC shall be not smaller than 6 AWG copper.
10.3.2 Where the TEBC serves a large rack row or high-density cabinet lineup, larger conductors may be appropriate to reduce dc resistance and surge impedance, but 6 AWG is the TIA-607-E minimum.
10.3.3 The TEBC shall be sized for the served equipment and the route length and shall be no smaller than the largest equipment bonding conductor it serves.
10.4 TEBC Routing
10.4.1 The TEBC shall be routed from the SBB to the bonded equipment in as short and direct a path as practical.
10.4.2 Where a TEBC follows a cable tray or ladder rack, it may be supported on the same pathway, provided that the TEBC is not used as the only bonding path for the tray itself.
10.4.3 The TEBC shall not be routed in a coil or unnecessary loop; loops add inductance and reduce the effectiveness of the bonding path at surge frequencies.
11 Rack and Cabinet Bonding
11.1 Equipment racks and cabinets house active telecommunications equipment whose chassis and grounding terminals shall be bonded to the telecommunications bonding network.
NOTE Bonding the rack itself does not automatically bond the equipment inside; both the rack frame and each individual chassis shall be considered. (11.2)
11.3 Rack Bonding Busbar (RBB)
● RBB provided in every equipment rack and cabinet
○ RBB provided in racks containing PoE / PDS / active equipment only
○ Not used — equipment bonded directly to SBB via individual TEBC drops
● Copper, electro-tin plated, predrilled for two-hole lugs
○ Copper, bare, predrilled for two-hole lugs
11.3.1 Each equipment rack and each cabinet shall be equipped with a Rack Bonding Busbar — a vertical or horizontal copper bus bar installed on the rack frame — to provide a common bonding point for the chassis of equipment mounted in the rack.
11.3.2 The RBB shall be bonded to the rack frame by a Rack Bonding Jumper or by listed paint-piercing bonding washers at the RBB-to-rack interface.
11.4 Rack Bonding Jumper (RBJ)
6 AWG (minimum per TIA-607-E)
4 AWG
Per equipment manufacturer (if larger than 6 AWG)
11.4.1 The Rack Bonding Jumper connects the rack/cabinet frame and its RBB to the SBB serving that telecommunications space, by way of the TEBC where the TEBC serves a row of racks, or by an individual conductor where the rack is bonded directly.
11.4.2 The RBJ shall be a 6 AWG copper conductor unless a larger size is required by the equipment manufacturer for the specific platform being installed.
11.5 Bonding to Painted or Anodized Rack Frames
NOTE Many equipment racks and cabinets are painted or anodized, and paint and anodizing layers are electrically insulating. (11.5.1)
● Listed paint-piercing bonding washer at every connection
○ Paint removed at connection point, sealed with corrosion-inhibiting compound after termination
11.5.2 Bonding connections to painted or anodized rack surfaces shall use listed paint-piercing or star-washer terminations that make contact with the underlying conductive metal, or the paint and anodizing shall be removed at the connection point to expose bare metal.
11.5.3 After connection, the cleaned area shall be sealed against corrosion with a listed compound.
11.6 Bonding Equipment with Power-over-Ethernet (PoE) Loads
NOTE Telecommunications equipment that supplies Power over Ethernet — switches and midspan injectors that deliver power to access points, IP cameras, IP phones, and similar devices — sources current onto the structured cabling and ultimately back to the equipment chassis through the device and the cable shield (where shielded). (11.6.1)
NOTE The chassis bonding path for PoE-sourcing equipment carries this return current. (11.6.2)
● Bonded to RBB via manufacturer-provided chassis bonding lug
○ Bonded to RBB via supplemental two-hole lug where manufacturer terminal is absent
11.6.3 The Contractor shall confirm that PoE switches are bonded to the RBB by the dedicated chassis bonding terminal where provided by the manufacturer, and that the bonding path back to the SBB is continuous and of low impedance.
NOTE A loose or high-resistance bond on a PoE switch produces measurable potential differences across the bonded shield network and can damage attached devices. (11.6.4)
12 Bonding of the Premises Distribution System
12.1 The Premises Distribution System (PDS) — the structured cabling between work area outlets, telecommunications rooms, and the equipment room — shall be bonded to the telecommunications bonding network at all metallic points where bonding is required for cable shield continuity, lightning protection, or surge dissipation.
12.2 Bonding of Shielded Twisted-Pair Cabling
Unshielded (UTP) — no cable shield bonding required
F/UTP (foil-shielded overall)
S/FTP (braid overall, foil per pair)
Fully shielded (foil and braid)
● Bonded to RBB via 6 AWG copper, two-hole lug at panel and RBB
○ Bonded directly to SBB via 6 AWG copper where no RBB is provided
12.2.1 Where shielded twisted-pair cabling (F/UTP, S/FTP, or fully shielded category cable) is installed, the cable shield shall be bonded to the telecommunications bonding network.
12.2.2 Shield bonding shall be made through the connecting hardware (patch panel and outlet) at both ends in accordance with the manufacturer's instructions and the requirements of TIA-568.2-E for shielded systems.
12.2.3 The patch panel housing or shield termination bus shall be bonded to the RBB or directly to the SBB by a copper conductor not smaller than 6 AWG.
12.2.4 Bonding of shielded cabling at only one end ("single-end grounding") shall not be used for category cabling at customer premises; TIA-568.2-E and TIA-607-E both require bonding at both ends of a shielded link to prevent the cable shield from acting as an antenna.
12.2.5 Single-end grounding is an outdated practice carried over from analog telephony and shall not be specified on this project.
12.3 Bonding of Optical Fiber Cable
NOTE Optical fiber cable does not require bonding at the cable itself, because the fiber is dielectric. (12.3.1)
● All-dielectric fiber — no bonding required
○ Armored or metallic-strength-member fiber — bonded at each end to RBB/SBB
12.3.2 Where the optical fiber cable contains a metallic strength member, a metallic armor layer, or a metallic moisture barrier, those metallic components shall be bonded to the telecommunications bonding network at each end of the cable.
12.3.3 Indoor armored fiber, indoor/outdoor armored fiber, and outside plant fiber with metallic components shall be bonded at the fiber distribution unit by means of the manufacturer-provided shield/armor bonding terminal.
☐ Bonding jumper across each cable tray splice
☑ Cable tray bonded to SBB in each telecommunications space
☐ Cable tray bonded to building grounding electrode system only where the tray is also a power pathway (coordinate with [[sync/grounding-and-bonding]])
12.4.1 Metallic cable tray, ladder rack, conduit, and innerduct used as telecommunications pathways shall be electrically continuous and bonded to the telecommunications bonding network.
12.4.2 Cable tray sections shall be bonded across mechanical splice plates with listed bonding jumpers where the splice plates alone do not provide reliable electrical continuity; manufacturer-supplied bonding straps or 6 AWG bonding jumpers are commonly used.
12.4.3 The cable tray system shall be bonded to the SBB serving the space at intervals not exceeding the spacing required by the tray manufacturer's listing, typically not exceeding once per room.
13 Bonding Grids in Equipment Rooms
13.1 Where the telecommunications space includes a raised floor and high-density telecommunications or computing equipment, a bonding grid (sometimes called a Signal Reference Grid, SRG, or Common Bonding Network, CBN, in the broader bonding literature) may be installed beneath the raised floor to reduce equipment-to-equipment potential differences at high frequencies.
NOTE ANSI/TIA-607-E recognizes the use of grids in equipment rooms where required by the served equipment; ANSI/TIA-942 imposes additional grid requirements for higher-tier data centers. (13.2)
13.3 When a Grid Is Required
● Not provided — single-point bonding per TIA-607-E only
○ Provided under raised floor with copper grid bonded to SBB at multiple points
○ Provided per TIA-942 / BICSI 002 (higher-tier data center)
13.3.1 A bonding grid should be installed where the equipment room serves high-speed networking equipment with shielded interconnects, where computing equipment with sensitive signaling shares a common space, or where the project includes a raised floor with metal pedestal-and-stringer construction that can naturally serve as part of the grid.
13.3.2 The decision to install a grid is project-specific; the Engineer shall identify the requirement on the contract drawings and the Contractor shall not assume that a grid is required absent explicit direction.
13.4 Grid Construction
6 AWG bare copper, 0.6 m × 0.6 m (2 ft × 2 ft) grid
6 AWG bare copper, 1.2 m × 1.2 m (4 ft × 4 ft) grid
4 AWG insulated copper, 1.2 m × 1.2 m grid
Per drawings — equipment manufacturer's grounding plan
13.4.1 Where a grid is provided, it shall consist of bare or insulated copper conductor not smaller than 6 AWG, installed in a regular pattern beneath the raised floor.
13.4.2 Conductors shall be bonded together at every crossing by exothermic welding or by listed irreversible compression connectors.
13.4.3 The grid shall be bonded to the SBB serving the space; where the served equipment manufacturer requires direct equipment bonding to the grid, the Contractor shall provide bonding conductors from the equipment to the nearest grid intersection in addition to, not in place of, the standard rack bonding path.
13.4.4 A grid is a permitted local supplement to the tree topology of TIA-607-E within a single equipment space; bonding the grid to the SBB at multiple points within that space is acceptable.
13.4.5 The grid shall not be bonded to the building grounding electrode system independently of the PBB; the single-point bonding rule still applies at the building level.
14 Outside Plant Entrance and Surge Protection
NOTE Telecommunications cables that enter the building from outside plant — copper service drops, metallic interbuilding tielines, antenna feedlines, broadband coaxial drops, and metallic-armored outdoor fiber — present a path for surge energy from lightning, induced voltage from nearby electrical faults, and power cross from accidental contact with power lines. (14.1)
14.2 Surge protection and entrance bonding shall be provided in accordance with NEC Article 800 (communications), Article 770 (optical fiber), Article 805, Article 840, and ANSI/TIA-607-E.
14.3 Entrance Bonding and Surge Protection Location
○ Within 6 m (20 ft) of cable entry, bonded to PBB
● At the entrance facility immediately adjacent to PBB
14.3.1 Entrance protection shall be installed as close as practical to the point where the outside-plant cable enters the building, in accordance with NEC 800.93 (length of grounding conductor) and 800.100.
14.3.2 The protector ground conductor shall be as short and as straight as practical and shall be bonded to the PBB or to the building grounding electrode system at the closest practical point.
NOTE A long, indirect, or sharply bent protector ground conductor adds impedance and reduces the effectiveness of the protector at surge frequencies. (14.3.3)
14.4 Surge Protectors — Paired Copper Communications
● Provided by serving carrier — Contractor bonds protector to PBB
○ Provided by Contractor where required for inter-building copper tielines
○ Not applicable — no outside-plant paired copper
● Not used
○ Provided at each station served by outside-plant paired copper
14.4.1 Surge protectors for paired-copper communications circuits — analog telephone service drops, T1/E1 metallic spans, and inter-building copper tielines — shall be listed to UL 497 (primary protectors) at the point of entrance and, where additional protection is required for connected equipment, to UL 497A (secondary protectors) downstream.
14.4.2 UL 497 primary protectors are required by NEC 800.90 on every conductor of an outside-plant paired-copper cable that is not shielded and bonded in a manner that already provides equivalent protection.
14.4.3 The Contractor shall confirm with the serving carrier whether the primary protector is provided by the carrier or by this Contractor; on most premises projects, the carrier provides the primary protector and the building scope provides the bonding to the PBB.
14.5 Surge Protectors — Data Communications and Fire Alarm
● Fiber only — copper inter-building runs prohibited
○ Copper permitted with UL 497B protectors at both ends
14.5.1 Surge protectors for data communications circuits exposed to outside-plant — Ethernet circuits routed between buildings on copper, fire-alarm circuits crossing between buildings — shall be listed to UL 497B and shall be bonded to the telecommunications bonding network.
NOTE Modern best practice is to avoid carrying Ethernet between buildings on copper at all; fiber should be used for any inter-building data path, eliminating the surge-path that copper inter-building runs create. (14.5.2)
14.5.3 Where copper inter-building runs are unavoidable, UL 497B protection at both ends shall be provided.
14.6 Surge Protectors — Coaxial
● Not applicable — no outside-plant coaxial
○ Provided at entrance and bonded to PBB
14.6.1 Surge protectors for coaxial outside-plant — broadband CATV drops, antenna feedlines, satellite drops — shall be listed to UL 497C and bonded to the PBB or the building grounding electrode system per NEC 820.93 and 820.100.
NOTE Coaxial primary protectors are commonly integrated into the broadband service entrance device. (14.6.2)
14.7 Bonding of Outside-Plant Cable Sheaths and Shields
14.7.1 Metallic sheaths, armors, and shields of outside-plant cables shall be bonded to the telecommunications bonding network at the point of entrance.
14.7.2 The bonding conductor shall be sized per NEC 800.100, NEC 820.100, or NEC 770.100 as applicable to the cable type, and shall terminate on the PBB or on the building grounding electrode system at the closest practical point.
NOTE The intent is that any potential rise on the outside-plant sheath — from a lightning strike, a power cross, or an induced surge — is delivered to the same earth reference as the building electrical and telecommunications systems, so no large potential difference develops across equipment connected to both systems. (14.7.3)
15 Materials
15.1 Bonding Conductors
15.1.1 Bonding conductors used in the telecommunications bonding network shall be copper conforming to ASTM B3 and ASTM B8.
15.1.2 Insulated bonding conductors shall be 600V-rated building wire with green or green-with-yellow-stripe insulation.
15.1.3 Bare bonding conductors shall be soft-drawn copper.
15.2 Busbars
15.2.1 The PBB, SBB, and RBB shall be solid copper bus bar conforming to ASTM B187, predrilled by the manufacturer for two-hole NEMA-pattern compression-lug terminations.
15.2.2 Electro-tin plating shall be provided where specified to reduce contact-surface oxidation.
15.3 Lugs and Connectors
● Listed two-hole compression lug, copper, NEMA hole pattern
○ Listed two-hole bolted mechanical lug, copper (where compression tool is not feasible)
15.3.1 All lugs used to terminate conductors on the PBB, SBB, and RBB shall be listed two-hole compression lugs sized for the conductor and the busbar hole pattern.
15.3.2 Lugs shall be of copper or copper alloy compatible with the busbar material.
15.3.3 Lugs shall be installed with the manufacturer's specified tool and die, and the die imprint shall be visible on the installed lug as evidence of proper crimp.
15.4 Bonding Hardware
15.4.1 All bolts, washers, and nuts used at bonding connections shall be of a material listed for the bonding application and compatible with the copper or tin-plated copper surfaces being joined.
NOTE Stainless steel hardware is the common standard. (15.4.2)
15.4.3 Galvanized hardware in direct contact with copper bus bar in damp environments shall not be used.
16 Connections and Terminations
16.1 General Connection Requirements
● Required — calibrated torque wrench used for every bonding connection
○ Required for PBB and SBB connections; rack terminations per manufacturer
16.1.1 Connections to the PBB, SBB, and RBB shall be made by listed two-hole compression lugs on standard NEMA hole spacing.
16.1.2 The bonding surface of the busbar at the connection point shall be cleaned of plating residue, contaminants, and oxidation immediately before the lug is bolted.
16.1.3 Where two lugs share a single bolt, the stacked lugs shall be of the same conductor size or arranged so the larger lug is closest to the busbar.
16.1.4 Stacking more than two lugs on a single bolt is not permitted.
16.1.5 Connections shall be tightened to the lug or busbar manufacturer's specified torque using a calibrated torque wrench.
16.1.6 Hand-tight or "go by feel" terminations shall not be accepted.
16.2 Compression Lug Installation
16.2.1 Compression lugs shall be installed with the manufacturer's specified hydraulic or mechanical crimp tool fitted with the correct die for the lug and conductor size.
16.2.2 The crimp shall fully form the die imprint on the lug barrel and shall not show oval deformation, conductor pullout, or incomplete crimp coverage.
16.2.3 A lug that fails visual inspection shall be cut off and replaced; field-modified lugs shall not be used.
16.3 Anti-Oxidant Compound
16.3.1 Anti-oxidant joint compound listed for the application shall be applied to the bonding surface and to the conductor strands at each compression lug termination, in accordance with the connector manufacturer's instructions.
16.3.2 Bare copper-to-copper connections in a dry, climate-controlled telecommunications space may omit anti-oxidant compound where the manufacturer permits.
16.3.3 Tin-plated copper terminations generally do not require compound, but if the bonded surface includes any aluminum component, compound is required.
17 Identification and Labeling
17.1 Busbar Identification
☑ PBB labeled "Primary Bonding Busbar (PBB) — per ANSI/TIA-607-E"
☐ Each SBB labeled "Secondary Bonding Busbar (SBB) — Room [number]"
☐ Bonding conductor to building grounding electrode system labeled at both ends
☐ Each TBB labeled at PBB and at SBB to indicate route and size
17.1.1 The PBB, each SBB, the RBB in each rack, the bonding conductor to the building grounding electrode system, and each TBB shall be permanently labeled to identify their role in the telecommunications bonding network.
17.1.2 Labels shall be engraved or machine-printed on a durable medium and applied at both ends of conductors that traverse multiple spaces.
NOTE The intent is that any future technician opening a telecommunications space can identify the bonding network without referring to original documentation. (17.1.3)
17.2 Warning Label
17.2.1 A warning label shall be applied at the PBB and at each SBB stating, in substance, that the busbar is part of the telecommunications bonding and grounding system and that connections shall not be removed or relocated without engineering review.
NOTE This label deters well-meaning maintenance technicians from "cleaning up" the apparent excess of bonding connections. (17.2.2)
18 Testing and Field Verification
18.1 The telecommunications bonding and grounding system shall be field-verified after installation and before the network is placed in service.
18.2 The Contractor shall perform the tests below and shall correct and re-test any item that does not meet the acceptance criteria.
18.3 Continuity Verification
☑ Bonding conductor — PBB to building grounding electrode system
☐ TBB — PBB to each SBB, end to end
☐ TEBC — SBB to each served rack/cabinet/pathway
☐ RBJ — RBB to rack/cabinet frame and to served chassis
☐ Shielded cable plant bonding — shield to RBB at each shielded patch panel
18.3.1 The Contractor shall verify electrical continuity of every segment of the bonding network from the PBB to each terminus, using an ohmmeter or low-resistance ohmmeter as required by the segment length.
18.3.2 Each segment shall be tested with the segment temporarily disconnected at one end so the measurement reflects that segment's path and not a parallel path through equipment or the building grounding electrode system.
18.4 DC Resistance Testing
0.051
0.050.10.250.51
Default: 0.1 ohms
18.4.1 The dc resistance of the bonding network from the SBB to the PBB shall be measured and recorded for each SBB.
18.4.2 ANSI/TIA-607-E does not impose a numerical resistance acceptance threshold by itself; the Contractor shall compare the measured value against the resistance computed from the as-installed TBB conductor size and length, and shall investigate any value significantly higher than the computed value, which indicates a poor termination, undersized conductor, or incorrect routing.
NOTE A value of 0.1 ohm is a common target for SBB-to-PBB resistance in moderately sized commercial buildings; data centers and projects with high-availability telecommunications systems typically require lower values. (18.4.3)
18.4.4 The Engineer shall set the project value based on the served equipment.
18.5 Bonding Connection Inspection
18.5.1 Each bonding connection at the PBB, SBB, and RBB shall be visually inspected for full lug seating, complete crimp die imprint, proper torque mark, and absence of corrosion or contamination.
18.5.2 Compression lugs that show incomplete crimp or that move under hand pressure shall be cut off and replaced.
18.5.3 Mechanical lug bolts shall be checked against the torque mark applied at installation; bolts that have rotated since installation shall be re-torqued.
18.6 Single-Point Bonding Verification
18.6.1 The Contractor shall verify that the telecommunications bonding network is connected to the building grounding electrode system at exactly one point — the PBB — and that no parallel bonding paths exist between any SBB and the building grounding electrode system, between the PBB and the building grounding electrode system through any path other than the BCT, or between separate SBBs except through the optional GE on the same floor.
18.6.2 This verification is typically performed by temporarily lifting the BCT at the PBB and confirming that the resistance from any SBB to the building grounding electrode system goes to open circuit; any remaining low-resistance path indicates an unintended parallel bond that shall be located and removed.
18.7 Test Reporting
18.7.1 All test results shall be recorded on the testing agency's report forms, including the test method, instrument identification and calibration date, ambient conditions, measured values, acceptance criteria, pass/fail determination, and the corrective action taken for any failed item.
18.7.2 Reports shall be included in the closeout submittals.
19 Installation
19.1 Coordination and Sequencing
19.1.1 The Contractor shall sequence the telecommunications bonding work so that the PBB and the bonding conductor to the building grounding electrode system are installed before the TBB is pulled, and the TBB and SBBs are installed before any TEBC, RBJ, or equipment bonding is made up.
NOTE Installing equipment bonding before the SBB is in place leads to ad-hoc, unrouted bonding conductors that have to be redone. (19.1.2)
19.2 Routing
19.2.1 Bonding conductors shall be routed as directly and as short as practical between their termination points.
19.2.2 Sharp bends, unnecessary loops, and routing in close parallel with high-current power conductors shall be avoided.
19.2.3 The bonding conductor shall not be bent to a radius smaller than the conductor manufacturer's specified minimum bend radius.
19.2.4 Conductors shall be supported per Raceways And Conduit and shall not be supported by piping, ductwork, or another trade's work. 19.3 Protection During Construction
19.3.1 Bonding conductors and busbars left exposed during construction shall be protected from damage by other trades.
19.3.2 Bonding terminations made before equipment is installed shall be coiled and bagged at the termination point to keep the conductor clean and free of damage.
19.3.3 Temporary bonds installed for construction shall be removed where they are not part of the permanent installation.
19.4 Connections to the Building Grounding Electrode System
19.4.1 The bonding conductor from the PBB to the building grounding electrode system shall be installed in coordination with the electrical Contractor responsible for the building grounding electrode system.
19.4.2 The connection at the building grounding electrode system end shall be made by exothermic welding or by a listed irreversible compression connector and shall be located as required by Grounding And Bonding. 19.4.3 The Contractor shall not connect the telecommunications bonding network to the building grounding electrode system at multiple points.
20 Delivery, Storage, and Handling
20.1 Bonding and grounding materials shall be delivered in the manufacturer's original packaging with listing marks intact.
20.2 Copper busbars shall be stored indoors in a clean, dry location with surface protection until installed; tin-plated busbars are forgiving of light handling, but bare copper busbar surfaces shall be protected from oxidation and contamination before installation.
20.3 Compression lugs and dies shall be stored dry.
20.4 Telecommunications protectors shall be stored in their original packaging until installation, and the listing labels shall remain attached to the installed device.
21 Warranty
1 year from substantial completion
2 years from substantial completion
21.1 Telecommunications bonding and grounding products that carry a manufacturer warranty against defects in materials and workmanship shall be warranted to the Owner.
21.2 The Contractor shall warrant the installation, including all bonding connections and the achievement of the specified continuity and resistance values, for the project warranty period.
21.3 Where the achieved SBB-to-PBB resistance is marginal relative to the acceptance criterion, the Engineer may require re-testing during the warranty period to confirm that the bonding network's integrity has not degraded.