What is the term used for a generator system that supplies power without the neutral connected to the utility system?

The term that describes a generator system supplying power without the neutral connected to the utility system is a separately derived system. This refers to a system in which the generator produces its own voltage and has its own grounding system. In such systems, the source of the power generation is completely independent of the utility’s neutral and grounding.

Separate derivation means that the system can be disconnected and operated independently from the utility, ensuring that any ground fault or imbalance does not impact the utility's system. This is particularly critical for safety, as it allows the system to operate safely under specific conditions without the risk of introducing faults back into the utility network.

In contrast, isolated systems may refer to systems that are designed to minimize interference but may not necessarily operate independently from the utility. Grounded systems usually imply connection to a ground reference point, often through the utility, while utility-derived systems are directly connected to utility sources, incorporating their grounding protocols.