Electrical grounding is defined as a physical wiring path that provides a route for short circuit current to flow to the earth should there be a fault in the power system. A grounding and bonding system needs this physical connection between electrical equipment and the earth.
Electricity in any industrial, commercial, institutional or residential wiring network is actually a flow electrons moving through wires. This electricity flow is constantly seeking the shortest possible route to the earth. Hence, if there is a short circuit, the electrical grounding and bonding system provides a direct route to the earth instead of through people and equipment. The grounding and bonding system becomes a controlled pathway to earth that is preferable to the current flowing through a person or piece of electrical equipment, which can be injurious and damaging.
How does electrical grounding work?
In any electric power circuit, there is an active wire which supplies the power, a neutral wire which carries that current back and a ‘grounding wire’ which provides an additional path for electrical current to return safely to the ground without causing danger to anyone in the event of a short circuit. he ground connection provides a path for electric current to flow, for instance from a circuit breaker or electrical box through an electrical connection to a cold water pipe that travels into the earth, and that assists the dissipation of energy into the actual ground.
The National Electrical Code and Canadian Electrical Code provide rules to govern the proper installation of ground wires in an electrical system to avoid potentially dangerous electric shock accidents.
Grounding And Bonding Definitions (Article 100: National Electrical Code)
Bonded (Bonding). Connected to establish electrical continuity and conductivity.
Bonding Conductor or Jumper. A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected.
Bonding Jumper, Equipment. The connection between two or more portions of the equipment grounding conductor.
Bonding Jumper, Main. The connection between the grounded circuit conductor and the equipment grounding conductor at the service.
Bonding Jumper, System. The connection between the grounded circuit conductor and the supply-side bonding jumper, or the equipment grounding conductor, or both, at a separately derived system.
Ground. The earth.
Ground Fault. An unintentional, electrically conducting connection between an ungrounded conductor of an electrical circuit and the normally non–current-carrying conductors, metallic enclosures, metallic raceways, metallic equipment, or earth.
Grounded (Grounding). Connected (connecting) to ground or to a conductive body that extends the ground connection.
Grounded, Solidly. Connected to ground without inserting any resistor or impedance device.
Grounded Conductor. A system or circuit conductor that is intentionally grounded.
Grounding Conductor, Equipment (EGC). The conductive path(s) installed to connect normally non–current-carrying metal parts of equipment together and to the system grounded conductor or to the grounding electrode conductor, or both.
Grounding Electrode. A conducting object through which a direct connection to earth is established.
Grounding Electrode Conductor. A conductor used to connect the system grounded conductor or the equipment to a grounding electrode or to a point on the grounding electrode system.
Neutral Conductor. The conductor connected to the neutral point of a system that is intended to carry current under normal conditions.
Neutral Point. The common point on a wye-connection in a polyphase system or midpoint on a single-phase, 3-wire system, or midpoint of a single-phase portion of a 3-phase delta system, or a midpoint of a 3-wire, directcurrent system.
Separately Derived System. A premises wiring system whose power is derived from a source of electric energy or equipment other than a service. Such systems have no direct connection from circuit conductors of one system to circuit conductors of another system, other than connections through the earth, metal enclosures, metallic raceways, or equipment grounding conductors.
Ungrounded. Not connected to ground or to a conductive body that extends the ground connection.