Can ungrounded conductors of circuits with a grounded neutral tap into two-wire DC or AC circuits that have at least two ungrounded conductors?

Grounded conductors, also known as neutral conductors, serve a crucial role in electrical systems by providing a return path for current and helping to stabilize voltage levels. When considering tap connections involving ungrounded conductors and circuits with grounded neutrals, the National Electrical Code (NEC) allows specific configurations under certain conditions.

Permitting the tapping of ungrounded conductors in systems that have at least two ungrounded conductors signifies that there are sufficient paths for returning current and that the system can continue to operate safely. Such arrangements can help maintain circuit functionality while allowing flexibility in circuit design.

Moreover, the regulation surrounding this practice emphasizes safety, as grounding and ungrounding principles are critical for preventing electrical shock hazards and ensuring the integrity of electrical installations. This validation within the code suggests that the circuits are sufficiently designed, and when safe practices are followed, utilizing ungrounded conductors in specific settings is an acceptable practice.

The other options address scenarios that either impose limitations not found in the NEC or indicate conditions that are not universally applicable across all electrical systems, such as specific restrictions based on the type of circuits or applications. Understanding the allowances and prohibitions within the NEC provides invaluable insight when designing or assessing electrical systems.