According to Section 250.50, what must be done with all grounding electrodes present at a building?

According to Section 250.50 of the National Electrical Code (NEC), all grounding electrodes present at a building must be interconnected, which means they must be bonded together. This requirement ensures that all grounding systems work harmoniously to provide a low-resistance path to earth in the event of a fault.

By bonding all grounding electrodes, it minimizes the risk of potential differences that may arise at different points, which is crucial for safety. If grounding electrodes are left unbonded, there could be a situation where one electrode is at a different potential compared to another, posing a shock hazard. Bonding creates a unified grounding system that improves the overall effectiveness of the grounding and bonding methods used in the electrical installation, ensuring that any electrical faults are safely directed to the ground, thus protecting both personnel and equipment.

This requirement enhances the overall safety and reliability of electrical installations and is critical for effective grounding practices.