Input distribution devices (ASU) are designed to connect internal power networks and electrical installations to external power sources and high-voltage cable lines. But the main functions of these devices are as follows: distribution (which is inherent in the very name of the unit) of incoming electricity between isolated consumers and protection of lines from overloads, short circuits and other similar troubles.
In other words, the input-distribution device also serves to ensure the electrical safety of high-voltage facilities and equipment. This is the most important purpose of the ASU. In addition, such a switchgear delimits the responsibility for the operation of high-voltage lines between the personnel of the city power grid and the consumer, since it is immediately possible to understand whoguilty of an accident or equipment failure. And all because the input-distributing device serves as a kind of watershed, a kind of border, on the one hand of which is the area of responsibility of the consumer, and on the other, employees of the city's power grids. This approach is also a kind of guarantee of uninterrupted power supply to a large number of autonomous consumers, including not only residential apartment buildings, but also large enterprises that require large capacities and stable operation of equipment.
To supply with a single cable electrical installations of low power, which belong to the third category of uninterrupted power supply, it is advisable to use a three-pole input-distribution device of the BPV type, rated for a current of one hundred to three hundred and fifty amperes, with one safety block and a switch. To ensure stable and stable operation of such equipment, sometimes YAZ700 series distribution boxes are used, equipped with a three-pole type automatic switch and rated for currents of 500-600 amperes.
For power supply to residential buildings up to five floors, an input-distribution device of the ShV type is installed. Of course, high-rise residential buildings, public buildings and small-scale enterprises require completely different capacities. At such facilities, as a rule, ASUs are used, which are structurally made in the form of switchboards for one- or two-way service. Any device of this typeconsists of input and distribution panels. It can also be a factory-made cabinet.
In general, there are countless different models of such devices, since in almost all major cities, electrical installation enterprises develop their own design solutions, produce their own models and series of ASUs. Often tailored to the particular facility where the equipment will be used.
For large plants and enterprises, which are characterized by the consumption of colossal energy capacities, input-distribution cabinets of the SHO-70 series are provided. They are also used in energy-intensive facilities such as substations. Devices of this type, designed for power exceeding 0.4 kW, are equipped with special circuit breakers with fuses or circuit breakers of the AVM and A37 series. Structurally, they can consist of separate blocks assembled at the installation site. Panels of such devices are installed directly at the walls of electrical rooms and are serviced from the front side. The switchboards themselves, in accordance with safety requirements, should be located in a convenient place where only employees serving them have free access.
Gas pipelines and other utilities are not allowed to pass through such premises. In some cases, it is allowed to install such high-voltage equipment in corridors, on landings. But at the same time, the cabinets must be securely locked, and the control handles must notbe brought outside or they should be made removable. It is unacceptable to install such devices in rooms with high humidity, as well as in places prone to flooding.
