Which of the following is a recognized grounding method under the NEC?

Ground rod grounding is recognized under the National Electrical Code (NEC) as an effective method for establishing a connection to the earth for grounding purposes. This method involves driving a conductive rod, commonly made of copper or galvanized steel, into the ground. The purpose of grounding is to provide a safe pathway for electricity to dissipate into the earth in the event of a fault, helping to prevent electric shock hazards and equipment damage.

Ground rods are typically installed at a specific depth and must meet certain resistance requirements to ensure the grounding system is effective. According to the NEC, ground rods are often used as part of a larger grounding system that may also include other grounding elements, such as ground plates or electrodes.

While the other methods listed might be used informally or in certain applications, they are not recognized or defined by the NEC as standard grounding practices. This highlights the importance of understanding compliant grounding methods to ensure safety and code adherence in electrical installations.