Which of the following is NOT considered an acceptable grounding electrode for a building or structure?

Which of the following is NOT considered an acceptable grounding electrode for a building or structure?

• A. A concrete-encased electrode with a plastic vapor barrier installed at the bottom
• B. A ground ring encircling the building and buried 36" deep
• C. A metal underground water pipe in contact with the earth for 40'
• D. Two 8' driven ground rods installed not less than 10' apart

Answer: (A)

A concrete-encased electrode, while commonly used for grounding, is not considered acceptable when it is installed with a plastic vapor barrier at the bottom. The grounding effectiveness heavily relies on the electrode maintaining proper contact with the soil to facilitate the dissipation of electrical currents. The presence of a plastic vapor barrier can inhibit this contact, compromising its function as a grounding electrode. In contrast, options such as a ground ring buried at an appropriate depth, a metal underground water pipe in contact with the earth, and driven ground rods are all conventional grounding methods recognized for their reliability and efficacy in establishing a connection to the ground. These methods promote effective grounding and bonding, integral to electrical safety in buildings.

A concrete-encased electrode, while commonly used for grounding, is not considered acceptable when it is installed with a plastic vapor barrier at the bottom. The grounding effectiveness heavily relies on the electrode maintaining proper contact with the soil to facilitate the dissipation of electrical currents. The presence of a plastic vapor barrier can inhibit this contact, compromising its function as a grounding electrode.

In contrast, options such as a ground ring buried at an appropriate depth, a metal underground water pipe in contact with the earth, and driven ground rods are all conventional grounding methods recognized for their reliability and efficacy in establishing a connection to the ground. These methods promote effective grounding and bonding, integral to electrical safety in buildings.