Previously, we observed that Art. 200 refers you to Art. 100 for the definitions of three terms that include the word grounding. Before looking at those definitions, let’s address the concept of grounding.
In the NEC, “grounding” is often to mean different things:
• Connecting to the earth (the soil). This is the Art. 100 definition.
• Providing an equipotential plane for equipment, as in “equipment grounding conductor.” This is actually bonding.
• The common reference plane (e.g., chassis “ground” or the green “ground” connection).
• Extending the ground connection. While semantically it seems logical to refer to this as grounding, electrically it does not. All methods for doing this involve the use of conductive metallic paths.
A way to avoid tragic mistakes is to think of anything that connects to equipment as a form of bonding (low impedance metallic path). You do not want to make load side grounding connections. In addition to providing no electrical benefit, such connections create ground loops. Worse, they are often created in place of a bonding connection; this leaves dangerous differences of potential on equipment.
The grounded conductor actually is grounded (at the service or separately derived source). Typically (but not necessarily), the grounded conductor is the system neutral. Don’t confuse it with a grounding conductor.
