Which type of AC systems is required to be grounded?

The requirement for grounding AC systems over 1kV that supply mobile or portable equipment is crucial for ensuring safety and protection against electrical hazards. Grounding these systems helps to prevent electrical shock and reduce the risk of fire or damage to equipment.

In applications involving mobile or portable equipment, grounding is particularly important because these systems may be moved around and connected or disconnected from power sources frequently. If a fault occurs (like a short circuit) while the equipment is in use, proper grounding facilitates a safe path for fault current to return to the ground, thus triggering overcurrent protective devices and minimizing the risk of electric shock to users.

While all AC systems require some form of grounding, the emphasis on systems above 1kV highlights the increased risks associated with higher voltages, which can cause significant harm if not properly grounded. This grounding requirement also ensures compliance with electrical codes and industry standards, which are designed to protect both personnel and equipment in industrial and commercial environments.

Other options do not capture the specific safety needs related to higher voltage systems and the unique circumstances of mobile or portable equipment, thereby narrowing the focus on the critical nature of grounding in these contexts.