NEC Commercial Electrical Practice Test

What is the maximum distance that interior metal water piping can be from the point of entrance to the building to be used as part of the grounding electrode system?

1. 3 ft

2. 5 ft

3. 8 ft

4. 10 ft

The correct answer is: 5 ft

The maximum distance that interior metal water piping can be from the point of entrance to the building for it to be used as part of the grounding electrode system is specified in the National Electrical Code (NEC). This distance is 5 feet. This requirement is set to ensure that the metallic water piping effectively serves as a grounding electrode, which is crucial for safety and to help prevent electrical shock hazards and equipment damage. The closer the water piping is to the entrance point, the more effective it is as a grounding pathway. If the distance exceeds 5 feet, the continuity of the grounding system may be compromised, leading to potential safety risks. Understanding this snippet of the NEC emphasizes the importance of maintaining specific distances for grounding purposes, as it impacts the overall safety of the electrical installation within a structure.