An alternating current system of 50 to 1000 volts is required to be grounded when ___.

In an alternating current system, grounding is a critical safety measure that helps protect both the electrical system and individuals from potential hazards. Grounding requirements can vary based on factors such as voltage levels, system configurations, and safety standards.

The statement that an alternating current system of 50 to 1000 volts requires grounding in the scenarios presented reflects a comprehensive understanding of the situations that necessitate grounding practices. When considering a system that operates at voltages between 50 to 1000 volts, grounding becomes essential if the system is either a 3-phase, 4-wire, wye-connected configuration with the neutral acting as the circuit conductor or a 3-phase, 4-wire delta-connected system with a midpoint as the circuit conductor, both of which can present unique grounding requirements.

In a wye configuration, the presence of a neutral wire is designed for safe operation and grounding helps ensure that any fault currents can effectively return to ground, minimizing risks. Similarly, in a delta-connected system that includes a midpoint as a circuit conductor, grounding is necessary to ensure safety and stability.

Since these grounding requirements apply to the scenarios described and also encompass any other considerations within the specified voltage range, this indicates that grounding must be addressed in diverse circumstances. Therefore, the option