Which of the following is NOT a cause of overcurrent?

Excessive insulation is not a cause of overcurrent in electrical systems. Overcurrent generally refers to a situation where the current exceeds the rated capacity of a circuit or device, which can lead to overheating and potential damage to electrical components.

Short-circuits, overloads, and ground faults are all scenarios that can contribute to overcurrent. A short-circuit occurs when there's an unintended connection with little or no resistance, leading to a dramatic increase in current flow. Overloads happen when a device or circuit draws more current than it is designed to handle, typically due to an excessive load placed on it. Ground faults arise when there's an unintentional path between a live conductor and the ground, also resulting in an increase in current flow.

In contrast, excessive insulation does not lead to an increase in current. Instead, it serves to prevent conduction and maintain safety in electrical systems. Therefore, it rightly identifies as the choice that does not cause overcurrent.