EC-1 COURSE: NEC Article 100 - Part Three

again , we will explain more important definitions inclued in NEC code Article 100 which will be used along this Course, toady we will show the term " Bonding" Definition.

It is the connection of two or more conductive objects to one another by means of a conductor such as a wire to provide continuity and conductivity.

the term "Bonding" shouldn't be confused with the term "Grounding" since the two terms has different definitions and applications although some consultants use them interchangeable especially in industrial, we need to define the term "Grounding" to understand its difference from the term "Bonding" as follows:

Grounding / Earthing:
It is the attachment of a bonded metallic system to earth, typically through ground rods or other suitable grounding electrodes for ensuring zero voltage.

Note: grounding is American standard term is equivalent to earthing which is a British standard term.

Comparison between bonding and grounding is given in the following table:

Connection between non-live conductive objects
Connection between live or non-live conductive objects to earth
Bonding is achieved by using bonding conductors, metallic raceways, connectors, couplings, metallic-sheathed cable with fittings, and other devices approved by the authority having jurisdiction as recognized for this purpose
Grounding is achieved by using a rod or other suitable grounding electrodes.
Bonding for grounded system provides the safety during fault current for persons
Grounding provides the safety during fault current for equipments without a need for bonding its enclosure
Bonding objects without grounding one of them gives no protection from stray currents but it protect from static charges
Grounding is independent on bonding it gives equipment protection disregard it is bonded to its enclosure or not.

Some definitions related to Bonding:

Bonding Jumper: see fig.1

This is the connection between noncurrent-carrying metallic components of the electrical system that are provided to ensure continuity.

fig(1): Boning Jumper

They may be bare, covered, or insulated conductors, or it may be a mechanical device, such as screws often provided to connect a neutral terminal bar to a service enclosure.

Equipment Bonding Jumper: 
see fig.2
These are bonding connections made between two portions of the equipment grounding system.

fig (2): Equipment Bonding Jumper

The purpose of the equipment bonding jumper is to provide the low-impedance fault-current path necessary to facilitate the operation of overcurrent protection devices in order to remove dangerous voltage potentials between conductive parts of building components and electrical systems

Main Bonding Jumper: see fig.3

A main bonding jumper provides the Code-required connection between the grounded system conductor and the equipment ground bus at the service equipment for a building or structure.

fig (3): Main Bonding Jumper

The connection between equipment ground and the grounding electrode system in ungrounded services is a “bonding jumper,” but not a “main bonding jumper.”

System Bonding Jumper: see fig.4

The conductor, screw or strap that bonds the equipment bonding conductor (metal parts of a separately derived system) to one of the system conductors or terminal

fig (4): System Bonding Jumper

The system bonding jumper provides the low-impedance fault-current path to the source neutral for fault current.

In the next topic, I will continue explaining other definitions from article 100.

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