A ground loop is best described as which of the following?

• A. A circuit that has more than one ground point with a voltage difference causing circulating current.
• B. A circuit with a single ground point.
• C. A circuit with no ground connection.
• D. A circuit with ground fault that trips the breaker.

Answer: (A)

Ground loops arise when a system has more than one ground reference that sit at different potentials. Those multiple grounds create a closed path, so current can circulate around the loop even though there isn’t a separate intentional return path. That circulating current can pick up noise and cause unwanted voltages in connected equipment. This description—more than one ground point with a voltage difference that leads to circulating current—best captures what a ground loop is. If there were only a single ground point, there would be no loop for circulating current to form. If there were no ground connection at all, there would be no return path. A ground fault that trips a breaker is a fault condition, not the normal looping behavior described here.