Final answer:
A ground loop is a circuit with multiple earth-ground connections, creating a voltage potential difference between them, which can cause system interference or damage.
Step-by-step explanation:
A ground loop is a circuit that has more than one point connected to earth's ground, with a voltage potential difference between the two ground points. This can occur in complex electrical systems where multiple components are grounded at different physical locations, leading to unintended current paths and potential interference or damage to the system. Ground potential is often considered to be zero, making the potential difference between two points the critical factor to measure. In practical terms, this is similar to how sea level is taken as h = 0 when calculating gravitational potential energy. Understanding and preventing ground loops is important for ensuring the safety and functionality of an electrical system.