Main switchboard (MSB)

Main Distribution Board (MDB)

The Main Distribution Board (MDB) is designed for receiving and distributing electrical energy in three-phase power networks with nominal voltages of 380 and 220 volts of alternating current at a frequency of 50 Hz. This device also includes elements for protection against overloads and short circuits.

Design Features

The MDB is a prefabricated metal structure consisting of several functional elements:

  • distribution panel;
  • incoming panel;
  • sectional panel;

Automatic circuit breakers, load switches, and various automation elements are used for arranging sectional and incoming panels. One of the key elements of the sectional panel is the automatic transfer switch (ATS), which is implemented based on modern microprocessor devices with logic controllers. The ratings and characteristics of the circuit breakers are selected depending on the parameters of the consumers who will receive electrical energy from the MDB. Often, metering devices are installed on the incoming panel, which monitor the consumption of electrical energy directly at the first switching device.

Application Area

The MDB is used to create a reliable power distribution network in administrative, residential, industrial, and other buildings and structures. These boards provide optimal protection against various deviations from the normal operating mode.

Main distribution boards are classified by the following parameters:

  • installation location;
  • type of installation;
  • method of protection against electrical shock;
  • number of phases in group and incoming circuits;
  • presence of switching devices with protective disconnection function from the power supply network;
  • electrical safety category;
  • presence of automation elements;
  • class of power supply reliability;
  • climatic performance;

When purchasing a main distribution board, it is important to consider the technical solutions for its installation. Depending on the installation location, there are outdoor and indoor MDBs, which differ in their degree of protection (IP) against external environmental influences such as humidity, mechanical damage, dust, and dirt. Additionally, the configuration of outdoor MDBs includes switching devices and automatic devices that can withstand sharp temperature changes and increased humidity.

Depending on the type of installation, MDBs can be wall-mounted, built-in, or floor-mounted. The most powerful and responsible sections of the electrical network are made using floor or built-in versions of MDBs.

Advantages of Using MDB

  • In addition to the functions of receiving and distributing electrical energy, the MDB is equipped with automation elements (ATS) that enhance the reliability and continuity of power supply.
  • The design of the main board allows for easy transportation and assembly from various panels.
  • Depending on needs, MDBs can be ordered with cable or busbar inputs.
  • The protection functions for outgoing lines allow for timely disconnection of damaged sections of the electrical circuit, maintaining uninterrupted power supply for other consumers.
  • The closed execution of the main distribution board guarantees restricted access to electrical installations and the possibility of installing metering units protected against vandalism and illegal actions.