Which connection is required for a 120/240 3-phase 4-wire electrical system?

In a 120/240-volt three-phase four-wire electrical system, a Delta connection is indeed essential. This system consists of three phases, and the four-wire configuration includes a neutral wire alongside the three phase conductors.

The Delta connection allows for the three-phase system to provide both 240 volts between any two phases and 120 volts between any phase and the neutral wire. This versatility in voltage options makes Delta suitable for applications requiring both voltages efficiently.

While Wye connections can also be used in three-phase systems, they typically provide a different voltage reference and are more commonly associated with higher voltage systems. Thus, a Delta connection is more prevalent and suitable for a 120/240 configuration due to its ability to deliver the required voltages directly from the system. Radial configurations are not standard four-wire systems, as they lack the necessary three-phase structure, and single-phase systems do not fulfill the requirement for a three-phase installation.