ESB Rozvaděče, a. s. manufactures and supplies USM universal measurement cabinets and their modification, SM– 1 measurement cabinets.
The general-purpose boxes for measurement purposes are used for the installation of measuring or registration equipment, to measure or register power consumption, mostly for large power consumers. The box can be used for the installation of common types of measuring, registration and auxiliary instruments, with a unified method of installation. The versatility of the box is given by the same basic design which makes it possible to place the instruments on pre-drilled panels or replace the instruments with others during the operation of the system. The manufacturer prepares the box and installs auxiliary instruments; the main measuring equipment is then installed and connected by the power distributor on site.
The 600 x 320 x 1000 mm box is made of a 1.5 mm steel sheet. The front side comprises a glass door with a lockable and sealable closing device. Behind the doors there is a tipping panel to which the measuring instruments are fixed. Below this, another fixed panel serves for the installation of auxiliary devices. The box is connected through four openings in the bottom, with PG16 bushings, or through four openings with bushing plugs in the roof. The back side can be provided with an assembly cross piece (console and supports) to fix the box to a wall. The assembly cross piece is supplied with the product. The surface of the box is treated with RAL 7032 (grey) powder varnish. Typically the box is manufactured to the IP 40/20 protection level, for indoor use.
All boxes are provided with internal illumination, switched on from the outside and a 230 V/50 Hz socket located on a fixed panel along with the corresponding circuit breaker.
Types of cases and their use:
The USM general-purpose measurement boxes are manufactured in four different basic types of design and in many variants:
USM – A = registration box for the receipt and registration of impulses
USM – B = measurement box with consumption meters and transmission modules
USM – C = measurement and registration box with additional registration equipment
USM – D = measurement box with two-tariff and maximum consumption meters
SM – 1 Metering cabinets:
The SM-1 metering cabinet is a modification of the USM box, with reduced dimensions and used for the installation of measurement and registration devices or evaluation equipment. Due to the dimensions of the box general-purpose types of consumption meters can be used. The manufacturer prepares the box and installs auxiliary instruments. The main measuring equipment is then installed and connected by the power distributor on site.
The 550 x 320 x 650 mm box is made of a 2 mm steel sheet. The front side comprises a glass door with a lockable and sealable closing device. Behind the doors there is a sealable tipping panel to which measuring instruments are fixed. Below this, another fixed panel serves for the installation of auxiliary devices. The box is connected through five openings in the bottom, with three PG 16 and two PG 13.5 bushings, or through five openings of similar design with bushing plugs in the roof. The surface of the box is treated with RAL 7032 (grey) powder varnish. The box is manufactured to the IP 54/20 protection level, in most cases for indoor use. Cases for outdoor use have to be modified so that the doors are made of plain material, without glass, and the box is provided with a roof. Part of the box equipment is a 230 V/50 Hz socket, fixed to a panel along with the corresponding circuit breaker, a terminal block for testing purposes, input clamps and other auxiliary instruments installed based on the needs of the customer. The box is fixed straight on to the wall through four openings on the back side using dowels.
Devices mounted on the tipping panel:
General-purpose consumption meter, auxiliary registration device or evaluation equipment
Devices mounted on the fixed panel:
Terminal block, terminal board for testing purposes, socket and other auxiliary equipment
Connection of the sm-1 terminal board:
Pins 1 to 4: inlet of the auxiliary voltage; inlet conductors from the current and voltage instrument transformers are connected straight on to the testing terminal board.