If a rod or pipe electrode cannot be driven into the earth due to rock, what is the minimum depth it can be buried?

The minimum depth for burying a rod or pipe electrode when it cannot be driven into the earth due to rock is specified in grounding and bonding regulations to ensure proper grounding effectiveness. According to the National Electrical Code (NEC), if an electrode cannot be driven to its required depth because of rock, it must be buried at a depth of at least 30 inches. This depth helps ensure that the electrode is adequately below the frost line in many areas and provides a reliable electrical connection with the earth for grounding purposes.

The specification of 30 inches takes into account different soil conditions and the need for effective grounding. At this depth, the electrode can still function well by making electrical contact with the earth and helps to mitigate issues like voltage surges or electrical faults.