In an ungrounded electrical system, what is the usual connection to Earth?

In an ungrounded electrical system, the usual connection to Earth is through distributed leakage capacitance. This occurs because, in an ungrounded system, the electrical conductors are not directly connected to the Earth, which would typically provide a path for fault currents and help maintain a stable reference voltage. Instead, the capacitance of the conductors to the surrounding environment, such as the ground, leads to a situation where small leakage currents can occur, allowing ungrounded systems to maintain some level of connection to Earth without direct grounding.

This type of setup is often the case in specific applications where it is desirable to avoid the disruptive effects of ground faults, allowing for continued operation even if one of the conductors were to become unintentionally energized with respect to ground. The distributed nature of the capacitance allows for a certain degree of stability in the system voltage, even while lacking a thorough grounding scheme.