What is commonly not seen in a solidly grounded system?

In a solidly grounded system, grounding is directly connected to the electrical neutral point of the source and provides a pathway for fault currents. This grounding method is predominantly used in systems that require reliable grounding for safety and operational stability.

The 480-volt, three-phase, three-wire configuration is typically not seen in solidly grounded systems because it lacks an explicit grounded neutral conductor. In three-wire systems, all conductors carry phase loads, which means that there is no return path through a grounded conductor for fault currents. This can lead to safety hazards, as there is not a reliable means to clear ground faults.

In contrast, other configurations like the 120/240-volt, three-phase, four-wire system and the 120/208-volt, three-phase, four-wire system include a neutral that is usually grounded, making them well-suited for solid grounding methods that enhance system safety. The single-phase, three-wire system also incorporates a grounded neutral that helps in safely managing fault conditions. Thus, the presence of a neutral conductor that is either grounded or ungrounded plays a crucial role in determining the type of grounding system being utilized, making the three-phase, three-wire system an unlikely candidate for solid grounding.