by Robert Coggins
Grounding is the single most important way to protect people and property, however not all commercial systems are adequately grounded.
This may be because bonding all systems is required to properly ground all systems in a commercial development.
As defined by the National Electrical Code (NEC) regarding safe installation of electrical wiring and equipment:
Grounding is, “Establishing a 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, “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.”
There is only one ‘ground’ and grounding the systems is the actual objective, but properly bonding several systems is a necessary procedure to achieve a well grounded system in a commercial structure. Consequently, any system that is inadequately bonded, or not bonded at all, is not grounded.
Properly grounding the technology systems will prevent the destruction of electrical components, and property damage due to lightning strikes and voltage transients. And it protects people from dangerous electrical exposure.
In a commercial development there are multiple technology systems installed in different areas of a building, often on multiple levels of a building or across many buildings of a campus. Bonding physically connects all pieces of each unique system, and all systems are physically connected, so that all systems are grounded. In short, any metallic component that is part of the data communications infrastructure must be bonded, including racks, ladders, enclosures, equipment, surge protection devices, and cable trays.
When the bonding process is completed to code, all systems are grounded. Understanding the importance of bonding to properly ground each of the technology systems is important to properly bonding all systems. For example, using two-hole lugs to get a more secure connection than with a one-hole lug which can loosen if jarred, reduces the risk of breaking the required connection to the ground. Or, by using antioxidant joint compound to improve the electrical conductivity and enhance the connection, you better ground the overall system.
The primary objective for grounding is to reduce the build-up of static charges (ESD) on equipment and material. It takes thousand volts for a person to even notice ESD in the form of a spark and the familiar zap that accompanies it, but even a small, unnoticed discharge can ruin semiconductors and potentially cost thousands of dollars.
The technology bonding infrastructure extends throughout a building, and includes the following five major components as described in BICSI’s 11th Edition Telecommunications Distribution Method Manual. BICSI is a professional association supporting the information transport systems (ITS) industry with information, education and knowledge assessment for individuals and companies.
- Telecommunications main grounding busbar (TMGB) – The TMGB is the central attachment point for all components of the telecommunications system’s grounding (bonding) infrastructure. Located in the telecommunications entrance facility, the TMGB is a predrilled copper busbar with holes for use with standard-sized lugs.
- Telecommunications grounding busbar (TGB) – The TGB is the attachment point for all telecommunications systems and equipment in a specific telecommunications space. Therefore, each telecommunications space throughout the building should have a TGB.
- Telecommunications bonding backbone (TBB) – The TBB bonds all TGBs with the TMGB as part of the telecommunications pathways and spaces (independent of cable).
- Grounding equalizer (GE) – Whenever two or more TBBs exist in a multistory building, they must be bonded together with a GE at the top floor and at every third floor in between.
- Bonding conductor for telecommunications (BCT) -From the telecommunications entrance facility, the TMGB is bonded to the building’s grounding electrode system with the BCT.
It may surprise some who are reading this to realize that many commercial installations are not properly grounded.
In the end, once grounding and bonding are understood, it becomes a business decision whether to invest in the safety of a well grounded, well bonded system. The decision comes down to “protect all systems” or risk the cumulative costs of the damage, repair, or replacement of system failures due to ESD, lightning strikes, and/or voltage transients.