If a grounding rod hits solid rock, how deep must it be buried in a trench?

The requirement for a grounding rod to be buried in a trench when it hits solid rock is typically defined by the National Electrical Code (NEC) and other relevant standards. According to these guidelines, if a grounding electrode cannot be driven to the required depth due to obstruction like solid rock, the grounding electrode must be buried a minimum of 30 inches below the surface.

This depth ensures adequate grounding for electrical systems, minimizing the risk of electrical shock and ensuring effective dissipation of electric currents. It is standard practice to adhere to this requirement because adequate grounding is crucial for safety, especially in areas with varying soil conditions.

While other depth options are present, the specified minimum depth of 30 inches serves to provide a balance of safety without being excessively deep, which would be impractical in situations where solid rock is encountered.