In a 4-wire delta system, what is the function of the neutral wire?

In a 4-wire delta system, the neutral wire serves the critical role of providing a return path for current. In electrical systems, especially in three-phase configurations like the delta system, a neutral wire allows for the return of the unbalanced load current. This is particularly important when loads connected to the phases are not equal, as it ensures that the current can return to the source in a balanced manner, which helps maintain system stability and performance.

Having a neutral wire can also facilitate the safe operation of single-phase circuits derived from the three-phase system, allowing these circuits to operate effectively without overload on the phases. In essence, the neutral wire helps in managing the flow of current throughout the system by providing a reliable return path, crucial for consistent voltage levels and overall system functionality.