Planning of electrical wiring in a house or apartment is a fundamental stage, on which not only the aesthetics of the interior, but also the safety of residents depends. One of the most difficult moments for beginners and even experienced masters is the choice of place and method of installation. switchboard. The built-in design looks much more attractive than the overhead, since it does not take up useful space and is not striking.
However, in order to implement this project, it is necessary to clearly understand which one is. niche It will be required for the selected boxing model. Errors in the design phase of the niche can lead to the fact that the shield simply will not stand in place or it will have to be dismantled along with a piece of wall. That is why the issue of dimensions, especially depth, requires detailed consideration even before the start of rough work.
In this article, we will analyze all the nuances associated with the size of the embedded shields. You will learn what the thickness of the case depends on, how to properly prepare the hole in the wall and what standards exist for different equipment series. Understanding these technical details will help avoid costly alterations and ensure the longevity of the entire power supply system.
Standard dimensions and depth of the enclosures
The depth of the embedded power shield is not a fixed value, but a parameter that varies depending on the manufacturer, series and number of modules. Most modern manufacturers, such as ABB, Legrand or IEKThey produce products that meet certain standard sizes. This is done to unify installation work and simplify the design of engineering networks.
Usually, the minimum depth for standard panels on 12-24 modules is about 80-90 mm. This is enough to place automatic switches and RCD in one row. However, if you plan to use more sophisticated equipment, the demands on the space inside the box increase. Wall thickness The body itself also plays a role, as it adds a few millimeters to the overall dimensions.
- 📏 For panels with 12-18 modules, the standard depth is often 85-95 mm.
- 📏 Models for 24-36 modules can require a niche depth of 100 to 120 mm.
- 📏 Large shields with 48 or more modules often have a depth of 130-150 mm or more.
It is important to note that the depth declared by the manufacturer is the outer size of the case. The actual working depth available for installation of equipment may be 10-15 mm less due to the thickness of the front and rear walls, as well as structural protrusions. Therefore, when calculating a niche, you should always take a stock.
Factors that influence the choice of niche depth
When determining the necessary dimensions of the recess in the wall, you can not rely only on the outer dimensions of the box. There are a number of internal factors that can significantly increase the required depth. First and foremost, it is about space-stock for switching wires. If the cable channel inside the shield is full, the wires will begin to press on the front panel, which can lead to its deformation or even breakage.
The second critical factor is the type of equipment being installed. Standard machines take up a little space, but if you use them, voltage-relayTimers, contactors or smart home automation units, their depth can be much greater than usual. Some specialized modules protrude backwards 20-30 mm longer than a standard single-pole machine.
⚠️ Attention: Never plan a niche "adjacent" to the size of the shield. Leave at least 20-30 mm of stock in depth for free placement of wires and ease of installation.
The material of the wall should also be considered. In concrete or brick to hollow out extra centimeters is more difficult than in the gas block, but it is in solid materials that the installation of shields of greater depth is most often required due to the laying of thick introductory cables. The introduction of a cable on top or bottom also affects how much space it will take to bend it inside the housing.
Features of installation in different types of walls
The technology of preparing a niche varies dramatically depending on the material of the walls. For full-body brick or monolithic concrete, the depth of the niche should be strictly calculated, since violation of the load-bearing structures is unacceptable. In such cases, it is often necessary to choose between a more shallow (small) shield or the use of an overhead option if sampling is only possible before the fitting.
With drywall constructions, the situation is different. Here, the depth of the niche is limited by the distance to the capital wall or the depth of the profile. If profile CW/CD has a depth of 100 mm, the shield depth of 120 mm will not stand up without removing the wall structure forward. In such cases, special shields for GCL are often used, which have fastenings for fixation on the sheet.
| Type of wall | Recommended depth reserve | Features of the sample | Typical niche depth |
|---|---|---|---|
| Monolithic concrete | 10-15 mm | Diamond drilling, neatly with fittings | 100-120 mm |
| Full-bodied brick | 15-20 mm | Puncture, possible chipping. | 100-130 mm |
| Aeroblastic/Penoblock | 20-30 mm | Easy to squash, but you need a dowel. | 120-150 mm |
| Drywall (GCL) | Profile by profile. | Cut-out by size, attachment to profile | 75-100 mm |
When working with foam blocks and aerated concrete, you should be especially careful. These materials are soft, and it is easy to choose a niche of the desired depth, but attaching a heavy metal shield requires the use of special chemical anchors or dowels for hollow structures. load-bearing capacity The walls are a limiting factor here.
☑️ Pre-strobbling check
Calculation of the place for cables and communications
One of the most common mistakes is to ignore the space required to enter and bend cables. The introductory cable, especially if it has a section of 10 mm2 or more, has considerable rigidity. It needs space to turn smoothly to the introductory machine. If the niche depth is insufficient, the cable will rest on the back wall or sidewall, creating a dangerous tension.
Modern shields often have removable plugs for inputting cables on top, bottom and back. When embedded in the wall, the rear holes are usually sealed with solution or remain closed, so the main flow of wires goes from above and below. For high-quality laying, it is necessary that the radius of the cable bend is not less than the permissible one, which directly depends on the free depth inside the box.
- 💡 The minimum radius of bending of the cable shall be at least 6 of its outer diameters.
- 💡 Introductory cables are better to start with a margin of length for convenient cutting.
- 💡 Use it. shell-shell or pipes to protect the cable in the passageway through the wall.
If you use a corrugated tube to supply lines, note that it also takes up space. In narrow niches, corrugated can interfere with closing the door or installing plastrons. In such cases, it is better to abandon the use of external corrugated inside the niche, switching to a double-insulated cable immediately before entering the shield.
Problems of narrow niches and ways to solve them
Sometimes there are situations when the chosen shield model is not physically fit into the prepared niche in depth. This may be due to errors in calculations, changes in the power supply project, or simply wall features. In such cases, you should not panic, there are proven technical solutions.
The first and most reliable way is to replace the equipment with a model with a lower depth. Many manufacturers have in the line "compact" series, which with the same number of modules have reduced dimensions. For example, switching from a metal shield to a plastic equivalent of the same series can win 10-15 mm depth.
⚠️ Attention: It is strictly forbidden to cut the ribs, guides or internal partitions of the shield to reduce its depth. This violates the IP protection class and fire safety of the structure.
If replacement of the shield is not possible, you can consider the option of removing part of the equipment. For example, the input machine and voltage relay can be carried out in a separate small box next to each other or use separate housings. There is also the practice of mounting a shield on pads, pushing it out of the wall, but this spoils the aesthetics and requires building walls or using decorative boxes, which is not always acceptable.
Technical requirements and safety of installation
Installation of the built-in electric shield is regulated by a set of rules SP 256.1325800.2016 and PUE. Although there is no strict millimeter-deep niche standard, there are requirements for accessibility, maintenance and fire safety. The shield shall be so installed that it is not possible to damage the cables and equipment mechanically.
It is important to ensure that the door is fully open 180 degrees (if designed) or at least 95 degrees to access the machines. If the depth of the niche is chosen incorrectly and the shield is drowned too deep or, conversely, protrudes, this can make it difficult to access the levers of the machines or make it impossible to read the meter readings.
In addition, the space around the shield in the wall should be filled with non-combustible material. The voids between the body and the wall are necessarily sealed with alabaster or plaster mixture. This provides additional fixation and prevents the spread of fire in the event of a fire inside the shield.
Frequently Asked Questions (FAQ)
Can I drown a shield in the wall?
Technically, this is possible if the back wall is removed, but it is not recommended. Sloping shields do not have the necessary rigidity of the frame for embedding, and their IP protection class will drop to zero if this modification is made. It is better to buy a model designed for this.
What is the minimum depth of a niche for a 12-module shield?
For most modern plastic shields, the minimum depth is about 85-90 mm. Metal models may require 100 mm or more. Always check the product’s passport (Installation Manual) before starting work.
What to do if you stumble upon a rebar in the sample?
Sawing load-bearing reinforcement in monolithic walls is prohibited. In this case, you need to either shift the niche to the side, or choose an overhead version of the shield, or reduce the depth of the niche and choose a flatter model of equipment.
Do I need to plaster the inside of the niche before installation?
Yes, the walls of the niche should be aligned with plaster. This will ensure a tight fit of the shield body to the wall around the perimeter, which is important for fixation and aesthetics. However, the finishing (wallpaper, painting) is better done after installing the shield, so as not to damage the coating.