Electrician's Licensing Practice Exam

What is the minimum length of bare copper required for a ground ring electrode?

1. 10 ft.

2. 15 ft.

3. 20 ft.

4. 25 ft.

The correct answer is: 20 ft.

The minimum length of bare copper required for a ground ring electrode is established by the National Electrical Code (NEC). A ground ring electrode is typically specified to ensure effective grounding by providing a low-resistance path for fault currents and to help stabilize voltage levels. According to the NEC, the bare copper conductor for a grounding ring must be at least 20 feet in length. This minimum length requirement is designed to provide sufficient surface area in contact with the earth to ensure adequate grounding. A longer grounding electrode also helps to minimize the resistance to ground, which is crucial during fault conditions. This requirement reflects standards for safety and efficiency within electrical systems, contributing to the overall reliability of grounding practices.