Definitions of Electrical Earthing / Grounding Terms

 

 

In electrical projects, both construction as well as maintenance, the following terms used on the Drawings, Specifications and in the actual Work site are equivalent and may be used interchangeably: "earth" and "ground"; "earthing" and "grounding". Besides, this article tries to rectify misinterpretation of some important terms often used by people involved in the electrical earthing / grounding work.

Electrical Earth Electrode

 

 


1. Electrical Earth

Conductive mass of the Earth whose electric potential at any point is conventionally taken as zero.

Electrical Earthinh / Grounding Points
Electrical Earthinh / Grounding Points

2. Earth Electrode

Conductor or group of conductors in initial contact with, and providing electrical connection to, Earth.

Electrical Earth Electrode
Electrical Earth Electrode

3. Exposed Conductive Part

Any part which can be readily touched and which is not a live part, but which may become live under fault conditions.

4. Extraneous Conductive Part

Any conductive part not forming part of the electrical installation such as structural metalwork of a building, metallic gas pipes, AC ducts, water pipes, heating tubes etc. and non-electrical apparatus electrically connected to them ie., radiators, cooking ranges, metal sinks etc. and non-insulating floors and walls.

Electrical earthing and bonding extraneous equipment Connection
Electrical earthing and bonding extraneous equipment Connection

5. Protective Conductor

Conductor used for some measure of protection against electric shock and intended for connecting together any of the following parts:

  1. Exposed conductive parts.
  2. Extraneous conductive parts.
  3. Earth electrode(s).
  4. Main earthing terminal or bar(s).
  5. Earthed point of the source(s).
Representative image of Electrical Earthing / Grounding System Schematics
Representative image of Electrical Earthing / Grounding System Schematics

6. Electrically Independent Earth Electrodes

Earth electrodes located at such distance from one another that maximum current likely to how through one of them does not significantly affect the potential of the other(s).

7. Main Earthing Terminal or Bar

The terminal or bar provided for the connection of protective conductors, including equipotential bonding and functional earthing conductors, if any, to the means of earthing.

8. Equipotential Bonding

Electrical connection to put exposed and extraneous conductive parts at a substantially equal potential.

Electrical earthing and bonding equipotential Connection
Electrical earthing and bonding equipotential Connection

9. Earthing Conductor

Protective conductor connecting main earthing terminal or bar of an installation to earth electrode or to other means of earthing.