Grounding - hdbk109220040046

DOE-HDBK-1092-2004

4.0 GROUNDING

This section presents general rules for the grounding and bonding of electrical installations.

Qualified workers should clearly understand the concepts of grounding practices as required by

the NEC. They should also clearly understand the definition and intent of the following

components of a grounding system that are explained in this chapter:

Grounded conductor

Grounding conductor

Grounding electrode conductor

Bonding jumper

Grounding electrode

4.1

REGULATIONS, CODES, AND REFERENCES

4.1.1

ENGINEERING SPECIFICATIONS AND DRAWINGS

Engineering specifications and drawings should identify the requirements for all components

and clearly illustrate the grounding electrode system, the grounding electrode conductor,

bonding points and bonding jumpers, and the connection point for the grounded conductor and

the grounding conductors. Where used for installation or construction purposes, these

specifications and drawings should also include detailed installation instructions.

4.2

CIRCUIT AND SYSTEM GROUNDING

Circuit and system grounding consists of connecting the grounded conductor, the equipment

grounding conductor, the grounding bus bars, and all noncurrent-carrying metal parts to ground.

This is accomplished by connecting a properly sized unspliced grounding electrode conductor

between the grounding bus bar and the grounding electrode system. There are three

fundamental purposes for grounding an electrical system:

To limit excessive voltage from lightning, line surges, and crossovers with higher voltage

lines.

To keep conductor enclosures and noncurrent-carrying metal enclosures and equipment at

zero potential to ground.

To facilitate the opening of overcurrent protection devices in case of insulation failures

because of faults, short circuits, etc.

4.3

EQUIPMENT GROUNDING

Equipment grounding systems, which consist of interconnected networks of equipment

grounding conductors, are used to perform the following functions:

4-1