In a 3-phase, 120/208-volt, 4-wire system with 750 kcmil aluminum conductors, what is the minimum size of the aluminum grounding electrode conductor to a pipe electrode?

To determine the minimum size of the aluminum grounding electrode conductor (GEC) to a pipe electrode in a 3-phase, 120/208-volt, 4-wire system with 750 kcmil aluminum conductors, the National Electrical Code (NEC) provides guidelines for sizing ground conductors based on the size of the largest ungrounded conductor in the system.

In this case, since the largest ungrounded conductor is 750 kcmil aluminum, the NEC requires grounding conductors to be sized accordingly to ensure adequate grounding and bonding. For aluminum conductors, the code generally stipulates that the grounding electrode conductor must be sized following the appropriate table in the NEC, which provides minimum sizes based on the size of the service entrance conductors.

In this scenario, if the largest conductor is 750 kcmil, the minimum size of the aluminum GEC to the pipe electrode is indeed #4. This ensures that the grounding system is robust enough to handle fault currents effectively, providing both safety and protection in the electrical system.

Understanding these guidelines helps ensure compliance with electrical safety standards and enhances overall system reliability.