Communications systems and equipment installed in buildings must comply with the specific rules provided in Article 770 and Chapter 8 of the National Electrical Code (NEC) . Even though these systems typically operate at lower energy levels, improper grounding and bonding can result in severe consequences for equipment and property and present shock hazards.
Grounding, in the simplest form, is the process of connecting an electrically conductive object to ground (the earth). Bonding is the process of connecting conductive objects together to establish continuity and conductivity. If a system or equipment is grounded, it is connected to the earth, and if objects are bonded, they are connected to electrically become one potential or as close to the same potential as possible. These two processes work in unison to provide safety for communications systems, equipment and property. Grounding and bonding for communications equipment and systems provide operational grounding and protective grounding functions.
Both grounding and bonding are functions necessary for safety when installing communications or other limited-energy systems. The purpose of grounding and bonding for communications and limited-energy systems and equipment is to provide a level of shock protection and limit damage from voltage surges created by lightning, line surges or unintentional contact with higher-voltage lines. Grounding protects the equipment and provides a path to the earth for lightning events; however, the grounding and bonding requirements of Chapter 8 in the NEC should not be confused with the requirements for lightning protection systems as provided in NFPA 780, “Standard for Installation of Lightning Protection Systems.”
It is important to recall that Section 90.1 indicates the purpose of the NEC is to protect people and property from hazards that arise from the use of electricity. Lightning is a powerful and unpredictable force that is not used by people. Electrical grounding and bonding rules in the NEC provide varying degrees of protection from lightning events—it is typically not the primary purpose but one of the functional and performance benefits. The requirements within the communications articles in Chapter 8 cover installations of primary protectors, usually located at the communications service cables point of entry to a building. See Part III within articles 805, 820, 830 and 840.
The 2020 NEC experienced significant restructuring of the communications systems rules. Chapter 8 of the NEC, “Communications Systems,” now consists of six articles: 800, “General Requirements for Communications Systems;” 805, “Communications Circuits;” 810, “Radio and Television Equipment;” 820, “Community Antenna Television and Radio Distribution Systems;” 830, “Network-Powered Broadband Communications Systems;” and 840, “Premises-Powered Broadband Communications Systems.”
During the 2020 NEC development process, significant redundancies were identified in each of these articles that facilitated the need to simplify the rules and reduce repetition in every Chapter 8 article. The 2020 NEC revisions resulted in a new Article 800 addressing the general requirements for communications systems to insert all common requirements in a single location that will apply to all Chapter 8 articles. Article 800.1 explains that the revised scope in 800 contains general requirements for communications systems that apply, unless modified in articles 805, 820, 830 or 840. The remaining rules in former Article 800 have been relocated to a new Article 805, “Communications Circuits.” The result is improved clarity and usability because all of the redundant requirements are now rolled into Article 800.
Similar grounding and bonding rules are applicable to each article and address requirements such as sizing of grounding electrode conductors, installation of bonding jumpers, installation of grounding electrode conductors and so forth. The definitions in Article 100 provide a foundation on which grounding and bonding requirements are built. The meanings of terms used in articles 770, 800, 805, 810, 820, 830 and 840 should be the same.
The 2020 NEC was also revised globally to include rules related to reconditioned equipment. It is now addressed in Section 800.3(G) and requires that the general requirements of 110.21(A)(2) apply. This rule indicated that reconditioned equipment is to be marked with the name, trademark or other descriptive marking of the organization responsible for reconditioning it and the date of the reconditioning. The equipment must be marked as reconditioned, and the original listing mark must be removed. There is an exception for industrial occupancies.