Definitions: Earth, ground, reference conductor system

Definitions: Earth, ground, reference conductor system

Earth and ground In almost all devices or systems, you should differentiate between the earth (earth conductor) and the common ground (reference conductor system/neutral connection). Earth and common ground are normally connected to each other in a certain place. However, there is a difference: NOTE: Earth only conducts fault currents and common ground conducts operational current and is often used as the common conductor for several signal circuits.

Earth

Earth is the conductive potential of our earth. The electrical potential of the earth is considered to be zero. Inside a system, earth is understood as being the protective conductor used for protecting people, animals and goods. Terms used as synonyms for Earth: Equipment grounding conductor, earth, protective earth, chassis or frame ground, station ground

Ground

This is the common base for all connected conductive inactive components of electrical equipment and is not a route for operational voltage even when a fault occurs. The common ground is the equipotential offset for a system and is used as a common ground plane for electronic circuits. The common earth plane is normally connected with the earth (grounded) in a stationary system. Common ground does not necessarily have to be connected with earth ground however (in airplanes for example). Common ground is found performing the following functions:  Equipotential plane for the reference conductor system of the electronics  Equipotential bonding and over voltage protection for all installations of metal, electrical systems, lightning protection system and grounding system  Protective function for people: Common potential is kept low in relation to earth potential so that a human would not be harmed by coming into contact with parts of the system  Rerouting over-voltages (caused by faults in the system, lightning) Terms used as synonyms for Common Ground: Equipotential bonding, neutral, switching ground, signal reference, signal ground, measurement ground, 0 V, reference conductor ground

Common ground examples Common ground examples:  Metallic structural elements of a building (framework, piping, etc.)  Motor housing  Metal cabinets, unpainted floor plates on housings  Metallic cable ducts  Transformer housing, machine bed plate  Yellow-green wire (PE-PEN) for grounding

Reference conductor, reference conductor systems The reference conductor for an electronic operation is the reference potential. It is connected with the common ground. The reference conductor system makes a galvanized connection of all 0 Volt wires that are required in the current loop of the electrical equipment. No voltage differences may exist between the various points of the electronic reference plane otherwise unintended signal voltages can occur.

Normally, several circuits are operated on a common reference conductor system for the exchange of necessary signals. Terms used as synonyms for Reference Conductor systems: Neutral (system)