Box for electric machines: types of boxes and their features + nuances of choosing and filling the box
When setting up an apartment or house network, you have to deal with the choice of electrical equipment.And if choosing an outlet is not so difficult, then buying a cable, machine or electrical panel requires knowledge and preliminary calculations.
Even an ordinary box for electric machines is not easy to purchase - the range of modern offers is so wide. We suggest you understand the variety of options and consider the criteria that are most important when choosing a box.
The content of the article:
Purpose of boxes for machines
Plastic and metal boxes perform the same function as distribution boards - they organize the operation of electrical equipment and serve for the electrical installation of protective devices. In the specialized literature you can find other names: box, box, shield, panel.
The main “filling” for filling the box consists of electric machines, however, other protective devices may be located next to them - RCDs and automatic devices.
Large boxes contain indicators, switches, timers, differential relays. But to equip the network of a private house or one apartment, installation of additional equipment is not necessary.
Boxes are installed in apartments, on floor areas, as well as on the street, if it is necessary to connect a private home to the power supply line. They are varied in design, assembly and functions.
Types of equipment according to GOST
According to legislatively adopted documents, both small boxes for 2 modules and large distribution cabinets-stations belong to distribution panels responsible for connecting electrical groups. The standards can be found in the editorial office GOST 32395-2013.
The shields are divided into apartment boxes and floor ones - at the place of installation. The next division is into distribution and accounting and distribution. The latter differ in the installation of the counter.
Thus, two broad categories can be distinguished:
- apartment — group and accounting-group;
- storey — distribution, accounting-distribution, accounting-distribution-group.
According to the installation method, all of the listed types can be wall-mounted or built into a specially prepared niche.
Distribution boxes are protected from electric shock. According to this indicator, they can belong to class I or II.
Some floor products are equipped with special compartments for low-current equipment. Apartment boxes come with or without an input device, designed for single-phase or three-phase circuits.
Design features of electrical boxes
Electrical products differ not only in the size of the housing. They are manufactured according to the requirements set out in GOST.
If the equipment is foreign-made, then it must also comply with Russian standards, otherwise the controlling organization simply will not allow connecting the apartment/house to the power supply main.
If only circuit breakers, it is not necessary to lock the door. But safety devices and shutdown devices require mandatory locking of the box.
Main parts of the circuit breaker box:
Structural elements designed either for hanging the box on a wall surface or for embedding it in a niche are required.
Technical characteristics of boxes
When choosing a box for an apartment or house, you need to take into account the number of automatic machines and other electrical equipment that you plan to install to protect the electrical network.
The main guideline should be a diagram indicating the devices grouped into groups. In addition, you need to decide on the type of box, exact size, protection class and ratings.
Electrical insulation and protection class
All electrical products, including those used in everyday life, must be protected from electric shock. This also applies to slot machines.
When turning off an automatic device or taking data from a metering device, the apartment owner must be confident in his safety.
According to GOST 12.2.007.0-75, there are five protection classes, from 0 to III.
All electrical boxes belong to class I or II electrical insulation:
- I class – metal boxes with working insulation and 1-2 grounding elements;
- II class – plastic boxes with reinforced insulation without grounding elements.
The electrical insulation class must be indicated in the technical documentation of the new product. You also need to consider the installation location and, depending on it, choose a box with degree of protection from dust and humidity - from IP44 to IP65.
If the box with machine guns is installed in the hallway, the lowest degree of protection is sufficient, but outdoor boxes must be marked at least IP54.
According to the installation rules, boxes for electrical devices cannot be installed in the kitchen, bathroom, combined toilet, attached swimming pool - that is, in any room where the humidity is higher than normal
Material of manufacture of the body and parts
There are 2 types of products based on the material they are made of: plastic and metal.
Metal. Boxes belonging to class I are coated with a protective coating that is resistant to corrosion. They can be equipped with additional parts made of other materials - grounding bars, contact clamps, connection devices.
Plastic. Most of the apartment panels are made from a special heat-resistant polymer - ABS plastic. This is an impact-resistant material that can withstand heating up to an average of +650°C. It is not prone to spontaneous combustion, and in the event of an emergency it can only melt, but not burn.
The design of the plastic box does not deform over time, as it takes shape during the heat treatment process. The surface is not exposed to ultraviolet radiation, which means it can be safely mounted on a pole or external wall of a building.
The housings of the polymer boxes are very light and easy to install. Modern boxes have squeeze-out entries for connecting wires and reversible doors.
If the box is planned to be installed on a wooden wall, then the requirements increase. Let's assume that the parts of class II boxes, built-in or external, must be resistant to wire heating up to +850°C.
Number of rows and modules
Another important characteristic is the dimensions of the box. Inside the box there are horizontally directed strips - DIN rails.
Each of them is designed for a certain number of places (modules). The width of one place is approximately 1.75 cm. For example, one machine takes up one place, and an electric meter takes up from 5 to 8.
The living room box is compact in size and has an average capacity of 12-36 seats, depending on the number of electrical circuits.
But manufacturers usually expand their range by increasing the size range, so in their collections you can find the smallest boxes for 2 switches, and large panels accommodating up to 180 modules.
Small boxes are useful when protective devices are located in several places. For example, if the RCD and metering device are installed on the street, and the group panel is installed inside the house. Option for urban installation: switch + meter on the site, distribution box in the hallway.
Nominal parameters of shields
All nominal values are indicated in the technical documentation; they must be taken into account when choosing apartment or floor boxes, as there are differences. For example, in urban high-rise buildings the nominal input voltage for apartment boxes is 230 V, while for storey boxes it can be either 230 V or 400 V.
There are no differences in the rated currents of 1-phase and 3-phase input devices; values from 25 A to 63 A are suitable for all types. Rated currents of individual machines and differential devices depend on power consumption and can vary from 6 A to 40 A.
It should be remembered that installing an apartment box as a floor distribution board is strictly prohibited.
Modifications for installation on site must be designed for a minimum of 2, maximum of 4 apartments. If more connections are required, an additional box must be installed.
Expert advice on selection and assembly
Taking into account the listed and other characteristics, choosing a suitable box even for setting up a network in a small apartment is not such a simple matter.
It is better to consult with a qualified electrician and, at a minimum, order a professional wiring project. Based on the diagram, you can assemble the electrical box.
Every little detail is important in the design of the future shield. As an example - ABB apartment box.
This is a box that is most suitable for installation of machines without purchasing additional parts. It costs more than a metal box without tires and frame, but is much more convenient to install and use.
The base of the case even has squeeze-out wiring hatches and small grooves for more convenient distribution of conductors inside the box.
For installation into the wall, dowels are used, and the gaps between the niche and the frame are covered with plaster or plaster. If the frame with slats is removable, then all work on installing the housing can be done together with construction activities for finishing the wall, and assembling the box can be done later.
We recommend paying attention to the products of brands that have long established themselves on the Russian market: ABB, Legrand, Viko, IEK, Makel, Schneider Electric.
Conclusions and useful video on the topic
Assembling the box - everything in order:
How to save on purchase and assembly:
The process of installing the shield and cabling:
It is better to entrust the selection and installation of distribution equipment to a qualified specialist - an electrician from the management company or a licensed electrician hired from outside to install electrical wiring.
But it is better for the homeowner to have information about the boxes - for taking urgent measures in an emergency or for minor independent repairs.
Do you have anything to add or have questions about choosing a box for an electric machine? You can leave comments on the publication, participate in discussions and share your own experience of purchasing, installing and filling the box. The contact form is located in the lower block.
Thanks for the detailed article. I had a lot of questions regarding the machine gun and the shield. When I was renovating my apartment, I searched the Internet for the necessary information, but, as luck would have it, I didn’t come across such material.