What voltage would be indicated on a 4-wire, open delta when measuring between any two ungrounded conductors?

In a 4-wire, open delta system, you have three phases of which only two are used to provide power across the loads. The voltage measured between any two ungrounded conductors in this configuration can vary depending on the specific connection and loads, which is why all the voltages listed are possible outcomes.

For instance, if you measure between two phases in a typical 3-phase system where the line-to-line voltage is defined, you may measure 208 volts, which is the common voltage in a 120/208 V system. However, in a different configuration, such as a 240 V split-phase system, you could also measure 240 volts between two phases. Similarly, if you're measuring in a context where each phase involves 120 volts, it is conceivable to measure 120 volts as well under certain conditions.

The interpretation of the open delta system allows for various voltage readings depending on how the phases are connected, which is why the correct response includes all three values. Hence, measuring between any two ungrounded conductors can yield 120 volts, 208 volts, or 240 volts, making the answer all of these possibilities valid.