Types of switchboards: brief description and purpose

There are several different types of switchboards, each of which has its own design features and scope. In this article, we give a brief description and purpose of the existing types of switchboards.

Classification of electrical panels by the method and place of installation

According to the installation method, switchboards are of three types: overhead, built-in and floor. Overhead shields are mounted directly on a wall, support or other building construction. The main distinguishing feature of the shields of this type is that its entire body is located outside.

Built-in shields are mounted in a pre-prepared recess in the wall. Thus, only the lid is visible from the outside, and the entire body is recessed into the wall.

The floor guard is installed directly on the floor surface or mounted on a special stand.

As for the installation site, in this case, the electrical panels are external or internal installation. The ability to install the shield outdoors is determined by its design features, namely the presence of appropriate housing protection.

There are several degrees of enclosure protection that indicate where the shield can be installed. The most common degrees of protection of the body of electrical panels:

• IP20, IP30 - shields installed indoors without increased humidity, since they do not have moisture protection, differ in the degree of protection against foreign objects;

• IP44, IP54 - shields have a higher degree of protection against foreign objects, have protection against moisture, are installed in rooms with high humidity, as well as outdoors, but subject to protection against the ingress of water;

• IP55, 65 - shields installed in rooms with aggressive environmental conditions, as well as outdoors. They have sufficient protection against moisture, rain and can be installed outdoors without additional protection. These switchgear enclosures have full protection against contact, differ in the degree of protection against dust - the first has partial protection against dust, the second - complete dustproof housing.

Outside the premises, the enclosures of billboard and floor types are installed. Shields are mounted on the walls of buildings and structures, on supports, stands, or directly on the equipment case.

Case Material

The case of electrical panels can be made of plastic or metal. Plastic shields (boxes) are used as small distribution shields indoors. The entire body of such shields is made of plastic, the cover is made of transparent plastic for the convenience of monitoring the status of protective devices and various devices.

Metal shields can be made entirely of metal, and can have glass or transparent plastic inserts on the front panel to be able to take meter readings, monitor the operation mode of various devices, etc.

DIN rails for installing electrical devices in all panels, regardless of the case material, are made of metal. Metal enclosures of panels are equipped with special mounting panels on which various devices and electrical devices can be mounted, as well as DIN railsallowing to mount the necessary modular devices.

To ensure the required degree of protection, the electrical panel body can have rubber seals, hermetic cable glands that provide dustproof and hermetic tightness.Metal enclosures of shields, as a rule, have locking devices that prevent unauthorized persons from entering them.

Flap body size

Switchboard enclosures are also classified by size. The size of the shield enclosure determines how many electrical devices and other devices can be mounted in it, how many cable lines can be wound up and whether there is enough space to connect them.

In this case, the main characteristics are:

• internal volume of the shield;

• number of modular seats on a DIN rail;

• mounting plate size;

• number of cable entries.

Classification of electrical panels according to purpose

The types of electrical panels discussed above can be equipped with various electrical devices, protective devices and have different purposes. Consider the main types of switchboards for their purpose.

VRU - introductory switchgear. Cabinets of this type are installed to receive electricity from a source - power transformers or from power lines of an electric network.

In this panel, switching and protective devices are mounted, and various protection and automation devices, metering devices can also be additionally mounted. This shield distributes electricity to other panels located in the building.

Main switchboard - main switchboard, in fact, is the same ASU and performs the same functions - receiving and distributing electricity to supply power to other purpose switchboards, which are discussed in the following paragraphs.

In large switchboards of enterprises, various electrical installations, measuring devices and metering devices are installed to control the operating mode of the switchboard equipment, as well as to account for the consumed electricity, both in general and on separate outgoing lines supplying the switchboards for other purposes.

Shield ABP - shield for automatic reserve entry. This shield is equipped with automation devices that monitor the parameters of the electrical network and switch the consumers' power from the backup power source in case of loss of power at one of the sources. One of the supply lines, a generator or a battery can act as a backup power source.

ЩО - lighting or heating shield. Electrical cabinets and other elements are installed in these cabinets for controlling lighting equipment or heating a room, equipment requiring heating.

ЩС - power shield, designed to power power consumers at the facility, where there is a separation of circuits and power consumers for their intended purpose. Also, this marking may mean that it is a communication shield.

Various telecommunication equipment, means of communication, and the collection of information from various equipment and facilities at the enterprise are mounted in the housing of the communication panel.

ЩЭ - floor board. It is installed on the floors of apartment buildings in a special niche or directly on the wall of apartment buildings, they are used to receive electricity from main switchboards (ASUs) and distribute it to several apartment panels.

ShchK - an apartment shield. It is installed on the floor or directly in the apartment. In this panel, a metering device for this apartment is installed, as well as protective devices.

Two shields can be installed - one on the floor, in it the introductory protective devices and metering device are mounted, the second shield is installed directly in the apartment, the electricity is distributed on several electrical wiring lines and protective devices are installed.

ЩЗ, ЩУ and ЩА - shield protection, control and automation. These types of switchboards can be found in electrical installations, a number of devices are mounted in these switchboards for implementing protection and automation of equipment of distribution substations, power plants, and industrial enterprises.

These shields are often combined into one shield, in which protection devices, automatics, and elements for monitoring and controlling a separate element of equipment, a group of equipment, or a section of the electrical network are mounted. The abbreviation SCHU may also indicate that it is a metering board.

ЩСН - shield of own needs. It is, in fact, the main switchboard, only this shield serves exclusively for powering devices located at the facility - the so-called own needs. Such panels are installed in electrical installations of electrical stations, distribution substations.

Own needs include: heating and cooling equipment, power on-load tap-changers of power transformers, equipment control circuits, lighting, space heating, etc.

Separate switchgears (switchboards) are installed to power the outgoing consumer lines. The same elements are mounted in the auxiliary shields as in the main switchboard and the switchgear, as well as automation devices, in particular, the automatic transfer switch.

ЩПТ - DC shield. It is used in electrical installations of stations, substations, enterprises for the reception and distribution of DC circuits. Reception of electric energy of direct current is carried out from storage batteries, special charging units, rectifier units.

Direct current is distributed on separate lines as an operating current for supplying various protection devices, automation and equipment control. In this panel, switching and protective devices are mounted, as well as measuring devices to control the charging mode of the batteries, the magnitude of the load and voltage.