A single rod, pipe, or plate electrode must have a resistance to ground not greater than what value?

The correct answer is 25 ohms. According to the National Electrical Code (NEC), a single rod, pipe, or plate electrode must have a resistance to ground that does not exceed 25 ohms. This standard is in place to ensure effective grounding of electrical systems, which is crucial for safety.

Maintaining a lower resistance to ground helps to minimize the potential difference that can occur during fault conditions, thereby reducing the risk of electric shock and damage to equipment. A resistance of 25 ohms or lower indicates that the grounding system is capable of effectively dispersing fault currents into the earth, enhancing system stability and safety.

Understanding this benchmark is fundamental as it aligns with widely accepted practices in the electrical field to ensure effective grounding and bonding of electrical systems.