This article is about Components and characteristics of Telecommunications Grounding and Bonding Infrastructure as per international codes and standards J-STD-607-A.
Understanding Telecommunications Grounding and Bonding Infrastructure: Components and Characteristics
Telecommunications grounding and bonding infrastructure is a critical part of any telecommunications system. It provides a safe and effective means of protecting the equipment and personnel from electrical hazards, static discharge, and lightning strikes. In this article, we will discuss the major components of the telecommunications grounding and bonding infrastructure, along with their characteristics.
- Grounding and Bonding Connectors All grounding and bonding connectors used in the telecommunications grounding and bonding infrastructure must be listed by a nationally recognized testing laboratory (NRTL) as required by the National Electrical Code (NEC). It is important to note that connectors are listed for the application, such as above ground or direct buried. This ensures that the connectors are designed and tested for the intended use.
- Grounding and Bonding Conductors All grounding and bonding conductors must be copper and may be insulated. When conductors are insulated, they should be listed for the application. The minimum bonding conductor size should be No. 6 AWG. It is important to note that conductors are listed for the space in which they are intended to be placed, such as riser systems or plenum spaces.
- Placing Conductors in Ferrous Metallic Conduit Grounding and bonding conductors should not be placed in ferrous metallic conduit. However, if it is necessary to place grounding and bonding conductors in ferrous metallic conduit that exceeds 1 m (3 ft) in length, the conductors must be bonded to each end of the conduit using a grounding bushing or a No. 6 AWG conductor, minimum.
- Labeling, Color-Coding, and Marking Each telecommunications grounding and bonding conductor must be labeled. Labels must be located on conductors as close as practicable to their point of termination in a readable position. Labels must be nonmetallic and include the information depicted in figure 5.1-1. The ANSI/TIA/EIA 606 standard provides additional labeling requirements.
The Bonding Conductor for Telecommunications, each telecommunications bonding backbone (TBB) conductor, and each grounding equalizer (GE) must be green or marked with a distinctive green color. This ensures that these conductors are easily identifiable and distinguishable from other conductors.
Telecommunications Main Grounding Busbar (TMGB)
In the world of telecommunications, the importance of grounding and bonding cannot be overstated. One crucial component of this system is the Telecommunications Main Grounding Busbar (TMGB). The TMGB serves as the dedicated extension of the building grounding electrode system for the telecommunications infrastructure. In this article, we will discuss the importance of the TMGB, its ideal location, description, bonding requirements, and installation requirements.
The Importance of the TMGB The TMGB serves as the central attachment point for the Telecommunications Bonding Backbone(s) (TBB) and equipment. It ensures that there is proper grounding and bonding of telecommunications equipment. With a single TMGB per building, the telecommunications equipment located within the same room or space can be easily grounded.
Ideal Location of the TMGB According to industry standards, the ideal location of the TMGB is in the telecommunications entrance facility. However, it should be located to minimize the length of the bonding conductor for telecommunications. The TMGB should also be accessible to telecommunications personnel and located near the panelboard, where provided.
Description of the TMGB The TMGB should be a predrilled copper busbar provided with holes for use with standard-sized lugs. It should be sized in accordance with the immediate application requirements and with consideration of future growth. The TMGB should have a minimum thickness of 6 mm (0.25 in) and a width of 100 mm (4 in), with variable length. It should also be listed by a nationally recognized testing laboratory. For reduced contact resistance, the busbar should be electrotin plated. If not plated, the busbar shall be cleaned prior to fastening of conductors, and an anti-oxidant should be applied to the contact area to control corrosion and reduce contact resistance.
Bonding Requirements for Telecommunications Equipment Where a panelboard is located in the same room or space as the TMGB, that panelboard’s alternating current equipment ground (ACEG) bus (when equipped) or the panelboard enclosure shall be bonded to the TMGB. The TMGB shall be installed as close to the panelboard as practicable, and clearances required by applicable electrical codes shall be maintained. Connections of the bonding conductor for telecommunications and the TBB to the TMGB shall utilize exothermic welding, listed compression two-hole lugs, suitable and equivalent one-hole non-twisting lugs, or other irreversible compression type connections. Two-hole lugs are preferred. The connection of conductors for bonding telecommunications equipment to the TMGB shall utilize exothermic welding, listed compression lugs, or other irreversible compression type connections. Two-hole lugs are also preferred.
Installation Requirements for the TMGB The TMGB shall be insulated from its support, and a minimum of 50 mm (2 in) separation from the wall is recommended to allow access to the rear of the busbar. The TMGB should be located to accommodate overhead or underfloor cable routing, and the mounting height of the TMGB should be adjusted accordingly.
Bonding conductor for telecommunications
Telecommunications equipment and systems require proper grounding to ensure the safety of people and equipment, as well as to prevent signal interference. One essential component of the telecommunications grounding system is the bonding conductor. This article will cover the basics of bonding conductors for telecommunications, including bonding to service equipment ground, sizing, and installation considerations.
The telecommunications bonding backbone (TBB) and the grounding equalizer (GE)
Bonding to the Service Equipment Ground According to industry standards, the bonding conductor for telecommunications must bond the telecommunications main grounding busbar (TMGB) to the service equipment (power) ground. Figure 5.3-1 illustrates the connection between the TMGB and the service equipment ground. This connection is necessary to provide a low-impedance path for fault currents and to prevent potential differences between the power and telecommunications grounding systems.
Sizing the Bonding Conductor for Telecommunications
The bonding conductor for telecommunications should be at least the same size as the telecommunications bonding backbone (TBB). The TBB is a conductor that interconnects all telecommunications grounding bars (TGBs) with the TMGB. The TBB and grounding equalizer (GE) are vital components of the telecommunications grounding system.
The TBB originates at the TMGB, extends throughout the building using telecommunications backbone pathways, and connects to the TGBs in all telecommunications rooms and equipment rooms. The GE interconnects multiple TBBs.
Design Considerations for the TBB and GE
The design of the TBB must consider the building’s construction, size, telecommunications requirements, and configuration of the telecommunications pathways and spaces. The TBB must be consistent with the design of the telecommunications backbone cabling system, permit multiple TBBs as dictated by the building size, and address routing to minimize the lengths of the TBBs.
The interior water piping system of the building cannot be used as a TBB, and the metallic cable shield cannot be used as a TBB. Whenever two or more TBBs are used within a multistory building, they must be bonded together with a GE at the top floor and at a minimum of every third floor in between. The GE should be sized as specified in industry standards.
Bonding and Sizing the TBB
The TBB must be a copper conductor, and the minimum conductor size should be No. 6 AWG. The TBB should be sized at 2 kcmil per linear foot of conductor length up to a maximum size of 3/0 AWG. The TBB may be insulated, and if so, the insulation must meet the fire ratings of its pathway. The sizing of the TBB does not account for the reduction or control of electromagnetic interference.
The TBB must be connected to the TMGB as specified in industry standards. While the TBB will carry some current under AC power ground fault conditions, it is not intended to provide the only ground fault return path. A TBB is not intended to serve as the only conductor providing a ground fault current return path.
Installation Considerations
The TBB conductors must be installed and protected from physical and mechanical damage. The conductors should be installed without splices, and where splices are necessary, they should be a minimum number and located in telecommunications spaces. Joined segments of a TBB must be connected using exothermic welding, irreversible compression-type connectors, or equivalent. All joints must be adequately supported and protected from damage.
Telecommunications Grounding Busbar (TGB)
When it comes to telecommunications systems and equipment, proper grounding is crucial for safety and performance. The Telecommunications Grounding Busbar (TGB) serves as the central grounding connection point for telecommunications systems and equipment in a given area. In this article, we’ll take a closer look at the TGB and its key features and installation considerations.
Description of the Telecommunications Grounding Busbar (TGB)
According to industry standards, the TGB should be a predrilled copper busbar that comes with holes for standard-sized lugs. It should have a minimum thickness of 6 mm (0.25 in) and a width of 50 mm (2 in), with variable length to meet application requirements and future growth considerations. Additionally, the TGB should be listed by a nationally recognized testing laboratory.
While it is desirable for the busbar to be electrotin-plated to reduce contact resistance, if it is not, it should be cleaned before fastening the conductors to the busbar. An anti-oxidant should also be applied to the contact area to control corrosion and reduce contact resistance.
Bonds to the Telecommunications Grounding Busbar (TGB)
To ensure proper grounding, all Telecommunications Bonding Backbone (TBBs) and other TGBs within the same space should be bonded to the TGB with a conductor of the same size as the TBB. The bonding conductor should be continuous and routed in the shortest possible straight-line path.
If a panelboard for telecommunications equipment is located within the same room or space as the TGB, its ACEG bus (when equipped) or the panelboard enclosure should be bonded to the TGB. The TGB should be installed as close to the panelboard as possible while still maintaining clearances required by applicable electrical codes.
If a panelboard for telecommunications equipment is not located within the same room or space as the TGB, consideration should be given to bonding the panelboard’s ACEG bus (when equipped) or enclosure to the TGB. Additionally, all metallic raceways for telecommunications cabling located within the same room or space as the TGB should be bonded to the TGB.
Connections to the Telecommunications Grounding Busbar (TGB)
To ensure secure connections, the TBB and the Grounding Electrode (GE) should be connected to the TGB using exothermic weld connections, listed compression two-hole lug connectors, suitable and equivalent one-hole non-twisting lugs, or other irreversible compression type connectors. Two-hole connectors are preferred.
Installation Considerations
The TGB should be insulated from its support, and a minimum separation of 50 mm (2 in) from the wall is recommended to allow access to the rear of the busbar. A practical location for the TGB is to the side of the panelboard (where provided). The vertical location of the TGB should take into consideration whether the bonding conductors are routed in an access floor or overhead cable tray.
Bonding to the metal building frame
Telecommunications systems are an essential aspect of modern-day businesses, and ensuring their safety and reliability is crucial. One important aspect of this is the proper grounding and bonding of the system components. In particular, bonding to the metal building frame is an important consideration to ensure safety and reliability. This article will outline the key considerations for bonding to the metal building frame in accordance with the Telecommunications Industry Association’s standard TIA-607-D.
Listed Connectors for Bonding
When bonding to the metal frame of a building, it is essential to use connectors that are listed for the intended purpose. This ensures that the connectors meet the appropriate safety standards and are suitable for the specific application.
Bonding to Vertical Steel Metal Frame
In metal frame buildings, where the steel framework is readily accessible within the room, each Telecommunications Grounding Busbar (TGB) and Telecommunications Main Grounding Busbar (TMGB) should be bonded to the vertical steel metal frame using a minimum No. 6 AWG conductor. This bonding ensures that any electrical current that might enter the building is quickly and safely discharged into the earth, protecting the telecommunications equipment and users.
Bonding to External Metal Frame
Where the metal frame is external to the room and readily accessible, the metal frame should be bonded to the TGB or TMGB with a minimum No. 6 AWG conductor. This bonding is crucial for the safety of the telecommunications system as it ensures that the metal frame is at the same potential as the telecommunications equipment, thus preventing electrical shock or damage to the equipment.
Bonding to Horizontal Steel Members
In some cases, it may be practicable to bond the TGB to horizontal steel members in a metal frame building, rather than to vertical column members. This is only suitable if the horizontal members are permanently electrically bonded to the vertical column members and the bonding distance is shorter. However, caution should be exercised when using this method, and it should only be done when it is safe and appropriate to do so.
Bonding in Reinforced Concrete Buildings
It is worth noting that TIA-607-D does not require bonding of the steel bars of a reinforced concrete building to the TGB or Telecommunications Bonding Backbone (TBB). This is because reinforced concrete provides sufficient grounding and bonding to meet safety standards.