Myths of Equipment Grounding and Bonding

Grounding is thought by many to be synonymous with electrical safety. “If equipment is grounded then it is electrically safe” gives a false sense of security. The process that many consider to be “grounding” can and may minimize the severity of electrical faults when performed with an understanding of what happens during an electrical fault. “Grounding” is very specific; it means a connection to the earth (ground). With respect to systems, such as transformers, generators, or batteries, “grounding” generally means providing a connection from one conductor of the system to an electrode that is buried in the earth. However, not all systems are grounded nor is the electrode always in the earth. When referring to equipment, the term “grounding” can have various meanings. It may mean bonding or it may mean a direct connection to the earth. The term “bonding” sometimes may mean “grounding,” and sometimes, it may mean a short or a long connection. Additionally, equipment “grounding” is often connected with ungrounded systems! This paper only addresses issues related to systems that are intentionally grounded. Several examples are presented to demonstrate the confusion of these two terms and the myths that go with them. Additionally, a discussion is provided concerning the myth that goes with the term “ground fault” and how “grounding” and/or “bonding” is applicable. In conclusion, a proposed definition for the fault return conductor is proposed to emphasize the need for a reliable low impedance path rather than an intentional connection to the earth.