What must a premises wiring system supplied by grounded AC service have according to the regulations?

A premises wiring system that is supplied by a grounded AC service is required to have a grounding electrode conductor in accordance with regulations. This conductor is essential for establishing a proper connection between the grounding electrodes, such as ground rods or plates, and the electrical system of the building. The grounding electrode conductor plays a crucial role in ensuring safety by providing a low-resistance path for fault currents to flow to ground, which helps to prevent electrical shock hazards and equipment damage.

The presence of a grounding electrode conductor is fundamental to the grounding system's integrity, ensuring that any fault currents can be safely dissipated into the earth. This grounding setup is vital in protecting both the electrical system and any individuals who may come into contact with it during normal operation or in the event of a fault. Proper grounding practices are a key aspect of electrical safety and compliance with the National Electrical Code (NEC).