A 3-phase transformer bank supplies what voltage to a 3-phase, 4-wire panelboard?

In a 3-phase, 4-wire panelboard system, the typical setup involves a transformer bank providing a combination of voltages that can be utilized effectively in various applications. The correct answer, 120/240 volts, reflects a commonly used transformer configuration for providing both line-to-neutral and line-to-line voltages.

In this configuration, the 120 volts represents the voltage between any one of the phases and the neutral wire, while the 240 volts represents the voltage between any two of the phases. This setup is highly advantageous for supplying standard household or commercial lighting and general power loads (which often require 120 volts), as well as larger equipment that might need the 240 volts.

This dual-voltage capability caters to diverse electrical demands within residential or commercial installations. The presence of a neutral wire allows for single-phase loads to operate at 120 volts, while three-phase loads can utilize the higher voltage of 240 volts for more efficient power delivery.

The other options, while they may refer to valid voltages in certain contexts, do not encompass the typical dual voltage supply provided by a 3-phase, 4-wire panelboard where a combination of 120/240 volts is standard.