How many grounding electrodes are required for a residential service system?

In a residential service system, the National Electrical Code (NEC) specifies that a grounding electrode system is essential for safety. While one grounding electrode is required for a residential service, having a single grounding electrode is generally deemed sufficient to provide a reliable electrical path to ground.

This electrode system typically includes ground rods, metal water pipes, or other approved grounding methods. However, if the installed grounding electrode meets certain criteria—such as being a metal underground water pipe or a concrete-encased electrode—it may satisfy the requirements alone.

It is advisable, especially for added safety and reliability, to use multiple grounding electrodes in certain scenarios. However, for the purposes of the basic requirement in standard residential installations, one grounding electrode is the minimum necessary to ensure the system is grounded, aligning with NEC guidelines.