When a 3Ø, 4-W supply system delivers 120/208 volts, how is the system connected?

In a 3-phase, 4-wire supply system delivering 120/208 volts, the system is connected in a wye configuration. This is because the wye connection allows for a phase-to-neutral voltage of 120 volts and a phase-to-phase voltage of 208 volts.

In a wye connection, each of the three phases is connected to a common neutral point, which provides the ability to tap off the lower phase-to-neutral voltage (120 volts) for standard single-phase equipment, while still accommodating the higher phase-to-phase voltage (208 volts) for three-phase loads. This dual-voltage capability is particularly useful in commercial and industrial settings where both types of loads are present.

The delta connection, while used in various applications, does not provide a neutral point and would typically present higher line-to-line voltages (such as 240/480 volts in a 3-phase system). Single-phase refers to a system with only one phase wire and is not applicable in this case since the question specifies a 3-phase system. Multi-phase generally implies more than two phases, which does not specifically pertain to the standard configurations of electrical supply systems commonly addressed in this context.