ESA Certified Alarm Technician Practice Exam

What does NFPA 70 article 250.118 set as the minimum length for a ground rod?

1. 4 feet

2. 8 feet

3. 6 feet

4. 10 feet

The correct answer is: 6 feet

NFPA 70, specifically article 250.118, specifies that the minimum length for a ground rod is 8 feet. The requirement for an 8-foot ground rod is essential for ensuring adequate grounding conductivity and providing a reliable path for electrical currents, especially in the event of a fault. This length allows for proper earthing in a variety of soil types and conditions, ensuring safety and compliance with electrical codes. Grounding is crucial for the protection of both electrical systems and individuals. An 8-foot grounding rod is necessary to meet the standards for effective grounding to lower the potential risk of electrical shock and equipment damage. Additionally, using the correct length helps to ensure that the grounding system has a low enough resistance to ground, which is vital for the operation of overcurrent protection devices. While other lengths are listed in the question, they do not align with NFPA requirements, which specifically state that 8 feet is the recognized standard for a ground rod.