Rod-type grounding electrodes should be spaced a minimum of 6 feet (1. 8 m) apart or according to the manufacturer's installation instructions. Rod, pipe, and plate grounding. A premise's wiring system supplied by a grounded service must have a grounding electrode conductor (GEC) connected to the service neutral conductor per Sec. 24 (A) (1) through (4): (1) General. The GEC connection to the neutral conductor at service equipment must be made at any accessible point. The core purpose of NEC Article 250 is threefold: to limit voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines; to stabilize voltage during normal operation; and to facilitate overcurrent device operation during ground faults. Of course, you can't bond something like conductive steel reinforcing bars that are inaccessible without chipping up the concrete so. According to 250.
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