For a separately derived system that is positioned 50 feet from a building and 100 feet from a water pipe electrode, how should it be grounded?

The appropriate grounding method for a separately derived system, which is positioned 50 feet from a building, is to connect it to the building grounding electrode system. This is because a separately derived system requires a proper grounding connection to enhance safety and ensure effective operation.

When connecting to the building's grounding electrode system, the grounding provides a low-resistance path for fault currents and helps mitigate the potential difference between the separately derived system and the building. This connection is crucial as it ensures that all systems remain at the same ground potential, minimizing the risk of electrical shock and equipment damage.

Using an independent ground rod, connecting to the nearest water pipe, or connecting to a local earth ground may not suffice due to the distance from adequate grounding systems or potential variations in ground resistivity. These methods could lead to grounding that does not meet the standards set forth by electrical codes, potentially exposing the building and the system to safety risks. Connecting to the established building ground is the most reliable practice for maintaining system integrity and safety.