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:

1. Grounded conductor

2. Grounding conductor

3. Grounding electrode conductor

4. Bonding jumper

5. Grounding electrode.

4.1 REGULATIONS, CODES, AND REFERENCES

Regulations, codes, and references for system, equipment, and personal grounding can be found in the following documents:

1. 29 CFR 1910

2. 29 CFR 1926

3. National Electrical Code (NFPA 70)

4. National Electrical Safety Code (ANSI C2)

5. NFPA 70E

6. ASTM F855, "Specifications for Temporary Grounding Systems to be Used on Deenergized Electric Power Lines and Equipment"

7. DOD FIPS-PUB-94, "Guidelines on Electrical Power for ADP Installations"

8. DOD MIL-HDBK-419A, (Volumes 1 and 2) "Grounding, Bonding, and Shielding for Electronic Equipment and Facilities (Basic Theory, Applications)"

9. EIA/TIA-607, "Commerccal Building Grounding and Bonding Requirements for Telecommunications"

10. IEEE 80, "Guide for Safety in AC Substation Grounding"

11. IEEE 142, "Recommended Practice for Grounding of Industrial and Commercial Power Systems"

12. IEEE 524A, "IEEE Guide to Grounding During the Installation of Overhead Transmission Line Conductors"

13. IEEE 1048, "IEEE Guide for Protective Grounding of Power Lines"

14. IEEE 1100, "Recommended Practice for Powering and Grounding Sensitive Electronic Equipment"

15. International Association of Electrical Inspectors, "Soares Book on Grounding" 16. NEMA 280, "Application Guide for Ground Fault Circuit Interrupters"

17. NEMA PB 2.2, "Application Guide for Ground Fault Protection Devices for Equipment"

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 busbars, and all noncurrent-carrying metal parts to ground. This is accomplished by connecting a properly sized unspliced grounding electrode conductor between the grounding busbar and the grounding electrode system. There are three fundamental purposes for grounding an electrical system:

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

2. To keep conductor enclosures and noncurrent-carrying metal enclosures and equipment at zero potential to ground.

3. To facilitate the opening of overcurrent protection devices in case of insulation failures because of faults, short circuits, etc. [See the fine-print note (FPN) to NEC Section 250-1¹.]