What type of fault occurs when there is contact between two phases in an overhead line?

The correct answer is that a fault that occurs when there is contact between two phases in an overhead line is known as a cross circuit. This type of fault typically results in a significant surge of current due to the direct connection between the two phases, which can lead to equipment damage and safety hazards.

In an overhead line system, when two phases come into contact, the electrical current finds an unintended path between the two conductors, effectively causing a short circuit condition between them. This can occur due to various reasons, such as equipment failure, weather-related impacts (like wind or ice), or physical damage to the line. Such faults need to be identified and cleared promptly to avoid extensive damage.

In contrast, other types of faults include open circuits, which involve a break in the electrical path, and ground faults, which occur when there's an unintended connection between a phase and the ground. These situations generally have different implications for operation and safety compared to a cross circuit situation. Identifying and understanding these variations is crucial for linemen to manage and respond to faults effectively.