Oklahoma Electrical Practice Exam

What is the smallest length of a rod or pipe electrode?

1. 6 feet

2. 8 feet

3. 10 feet

4. 12 feet

The correct answer is: 8 feet

In electrical installations, the length of a rod or pipe electrode is specified primarily for grounding purposes. The National Electrical Code (NEC) outlines these requirements to ensure safe and effective grounding systems. The minimum length for a ground rod or pipe electrode is established to provide adequate surface area for effective grounding to the earth, which is essential for dissipating fault currents and preventing electrical shock hazards. The correct answer of 8 feet as the smallest length for a rod or pipe electrode aligns with NEC requirements, ensuring that the electrode has sufficient vertical depth to make contact with a stable soil structure that can provide a reliable ground connection. This length also helps in avoiding excessive resistance between the electrode and the ground, which can impair the grounding system's overall effectiveness. Grounding is crucial for the safety of electrical systems, protecting both equipment and personnel. Knowing this minimum length is vital for ensuring compliance with safety standards in electrical work.