Electrical Codes for Grounding
By Dave Rongey
Summary: Listing of electrical codes for grounding with examples of electrical grounding codes for home electrical wiring.
Electrical Code Definitions for Grounding Home Electrical Systems
Understanding the Importance of Electrical Grounding
Grounding and Bonding
Grounding and Bonding All grounding electrodes that are present at each building or structure served shall be bonded together to form the grounding electrode system.
Code Adoption Information: The codes shown are examples only and may not be current or accurate for your application or jurisdiction. Contact your local building authority for complete information.
NATIONAL ELECTRICAL CODES
NEC 250.5 Grounding and Bonding
Grounding and Bonding Electrodes include a metal underground water pipe in direct contact with earth for 10 feet or more, a metal frame of a building or structure, a concrete encased electrode or a ground ring
NEC 250.28 Grounding and Bonding Grounding and Bonding
A main bonding jumper or the green bonding screw provided by the panel manufacturer shall be installed in the service panel.
NEC 250.32 Grounding and Bonding
Grounding and Bonding Buildings supplied by a branch circuit or feeder shall have an equipment grounding conductor run with the supply conductors and connected to the grounding electrode system at the separate building.
NEC 250-50 A premise's electrical service shall be connected to a grounding electrode system consisting of a metal underground water pipe in direct contact with earth for 10 feet or more, if available on the premises, and a supplemental electrode (a rod, pipe, or plate electrode.) An additional electrode shall supplement the buried water pipe electrode.
NEC 250.53 Grounding and Bonding Grounding and Bonding
A metal underground water pipe shall be supplemented by an additional electrode, such as an approved rod, pipe or plate electrode.
NEC 250.64 Grounding and Bonding Grounding and Bonding
The grounding electrode conductor shall be continuous, securely fastened and protected from physical damage.
NEC 250.66 Grounding and Bonding Grounding and Bonding
The size of the grounding electrode conductor shall be determined by the size of the service-entrance conductors, per the following chart:
Equivalent Size of Service Entrance Conductor Size
of the Grounding Electrode Conductor
Copper - - - Aluminum - - - Copper Aluminum
..4 AWG... ... ..2............ ........8*........6
..1 AWG..... ...2/0............. . ...6.........4
..2/0 or 3/0.... .4/0 or 250.......4.........2
*The conductor that is the sole connection to a rod, pipe or plate electrode is not required to be larger than #6 AWG copper, however smaller conductors require physical protection.
NEC 250.104 Grounding and Bonding Grounding and Bonding
The interior metal water piping and other metal piping that may become energized shall be bonded to the service equipment with a bonding jumper sized the same as the grounding electrode conductor.
NEC 250.134 Wiring Methods Grounding
All electrical equipment, metal boxes, cover plates, and plaster rings shall be grounded. All switches, including dimmer switches, shall be grounded.
NEC 408.41 Wiring Methods Grounded Conductor
Each grounded conductor shall terminate within a panel board in an individual terminal that is not used for any other conductor.
Residential Electrical Code Examples for Grounding