What is considered a concrete-encased electrode?

• A. Two 10 ft 1/2 inch diameter bare steel reinforcing bars connecting together by the usual steel tie wires encased in 6 inches of concrete located horizontally in the building foundation and in direct contact with the earth
• B. A copper rod 8 feet long
• C. A water pipe near the building
• D. A single steel reinforcing bar 4 feet long

Answer: (A)

A concrete-encased electrode is a grounding path formed by metal that is embedded in concrete within the building’s foundation and in contact with the earth. The concrete surrounding the metal provides the conductive path to soil, creating a robust grounding electrode.

The described setup fits perfectly: two bare steel reinforcing bars of substantial length are connected together with tie wires and encased in a thick section of concrete in the foundation, directly contacting the earth. This is exactly how a concrete-encased electrode is implemented, leveraging the reinforcing steel buried in concrete to establish a reliable ground.

Other options don’t meet this configuration: a copper rod alone isn’t embedded in concrete; a water pipe near the building isn’t the concrete-encased type; and a single reinforcing bar not stated as encased in concrete wouldn’t qualify as a concrete-encased electrode.