Course Content
Article 200 – Use and Identifications of Grounded Conductors
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Article 210 Branch Circuits
Article 210 of the National Electrical Code (NEC) covers the requirements for branch circuits, which are the circuits that supply power to the outlets, lighting fixtures, and other loads in a building. In this lesson, we will discuss the key requirements of Article 210.
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Article 215 Feeders
Article 215 of the National Electrical Code (NEC) covers the requirements for feeders, which are the circuits that supply power from the service equipment to the branch circuits in a building. In this lesson, we will discuss the key requirements of Article 215.
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Article 230 Services
In summary, Article 230 provides specific requirements for the installation of service conductors and equipment to ensure safe and reliable delivery of electrical power to buildings and structures.
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Article 242: Overvoltage Protection
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NEC Chapter 2 Wiring and Protection
About Lesson

Grounding electrodes play a crucial role in establishing a safe and effective grounding system for electrical installations. In this lesson, we will discuss the different types of grounding electrodes and how to properly install and maintain them according to the National Electrical Code (NEC).

Overview:

Grounding electrodes are conductive materials that are buried or driven into the earth to provide a low-impedance path for fault currents to flow to the earth. These electrodes are typically made of copper, steel, or other conductive metals and must be electrically connected to the grounding system of the electrical installation.

Types of Grounding Electrodes:

There are various types of grounding electrodes recognized by the NEC, including:

  1. Metal Water Pipe: This type of grounding electrode is a conductive metal pipe that runs underground from the building’s main water supply into the earth. It must be in direct contact with the earth for at least 10 feet.

  2. Ground Rod: This type of grounding electrode is a long, cylindrical metal rod, typically made of copper or steel, that is driven into the earth. It must have a minimum length of 8 feet and be driven vertically into the earth.

  3. Concrete-Encased Electrode: This type of grounding electrode consists of a reinforcing steel bar or wire mesh that is encased in concrete and buried in the earth. The concrete must have a minimum thickness of 2 inches and be in direct contact with the earth.

  4. Ground Ring: This type of grounding electrode is a continuous loop of conductive material that is buried in the earth around the perimeter of a building or structure. It must be at least 20 feet in length and have a minimum cross-sectional area of 250 kcmil.

  5. Plate Electrode: This type of grounding electrode is a flat metal plate, typically made of copper or steel, that is buried in the earth. It must have a minimum area of 2 square feet and be installed horizontally in a trench that is at least 30 inches deep.

Installation and Maintenance:

The installation and maintenance of grounding electrodes must comply with the NEC requirements. The electrodes must be installed in a manner that ensures low resistance to ground and provides effective fault current path. Here are some key installation and maintenance requirements:

  1. The grounding electrode conductor must be continuous and unspliced from the electrode to the point of connection to the grounded conductor.

  2. The grounding electrode conductor must be securely fastened and protected from physical damage.

  3. The electrode must be installed in a location that is accessible for testing and maintenance.

  4. The electrode must be tested for resistance to ground after installation and periodically thereafter to ensure that it remains within the acceptable range.

  5. Any corrosion on the electrode or the grounding system must be removed, and damaged electrodes must be replaced promptly.

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