The neutral conductor is a central component of electrical energy distribution systems, especially in AC networks. It serves as a return conductor for the current and enables the formation of a reference potential (usually earth potential) for the power supply. In conjunction with transformers, the neutral conductor plays a decisive role in the safety, functionality and stability of the power grid.
In a three-phase alternating current system, also known as a three-phase system, the connection consists of three phases or phase conductors (L1, L2, L3) and a neutral conductor or neutral wire. The lines or cables and conductors carry the electrical energy to the consumers. While the phases or phase conductors carry the alternating voltage, the neutral conductor serves as a return conductor via which the current flows back in the event of an unbalanced load.
This difference between the phase conductors, the phases and the neutral conductor is central to understanding the circuit correctly. If the current flows in the outer conductors or phases to the load, it flows back via the neutral conductor, creating a closed circuit. If the load is symmetrical, hardly any current flows in the neutral conductor, but more if the load is asymmetrical.
Transformers convert electrical energy from one voltage level to another and are an essential component of electricity grids. The neutral conductor can be integrated in various ways:
The neutral conductor is often confused with the protective conductor. These are two different types of conductorwith different functions. The neutral conductor is part of the electrical circuit and feeds the current back, while the protective conductor is only there to protect against electric shocks and, in the event of a fault, diverts current to earth.
A socket outlet therefore contains the outer conductor, the neutral conductor and the protective conductor. Each of these conductors fulfills a different function and it is important to connect them correctly to ensure safety.
In households and businesses, the neutral conductor is essential for connecting single-phase loads to a three-phase network. Most electrical appliances, from coffee machines to computers, are single-phase loads that receive power via the phase and neutral conductor.
Modern electronics often generate harmonics that can place a greater load on the neutral conductor than originally assumed. Therefore, cables and conductors must be designed correctly to avoid overloads.
In Europe, the neutral conductor is marked light blue as standard in accordance with DIN VDE standards so that it can be clearly distinguished from the phase conductor and the protective conductor. Correct labeling is important to avoid confusion during installation and maintenance.
In conjunction with an RCD, the neutral conductor is monitored in order to quickly interrupt the circuit in the event of residual currents and thus protect people and systems.
The neutral conductor is an indispensable component of a functioning AC grid. It ensures that the current flows back safely in the event of an unbalanced load and that the network remains stable. The difference between the neutral conductor and the protective conductor must be clearly noted.
Without the neutral conductor, safe operation of single-phase appliances via a socket outlet would not be possible. The neutral conductor also contributes to a safe power supply through its integration in transformers and the star connection.
Correct routing, labeling and protection of the neutral conductor are essential to ensure that an electrical circuit functions reliably and does not pose any danger to people or appliances.
+49 (0) 60 62 - 9 42 50 
info@bre-trafo.com