A modern apartment is oversaturated with powerful electrical appliances, and old wiring with plugs on the landing simply cannot withstand such a load. That is why the question of how to assemble a shield in an apartment becomes critically important for the safety and comfort of residents. A properly designed and assembled electrical panel will protect expensive equipment from power surges, and people from electric shock due to leaks.
Self-assembly of a switchboard requires deep knowledge of electrical engineering, understanding of the principles of operation of protective automation and strict adherence to PUE standards. This is not just a mechanical connection of wires, but the creation of a complex engineering system where each element performs its own function. Errors at the design or installation stage can lead to a fire or failure of the entire electrical network.
In this article we will analyze in detail all the stages of creating an electrical panel: from selecting the housing and calculating the loads to final switching and testing. You will find out what is different RCD from a differential machine, why you can’t save on a contact group and how to correctly distribute consumers into groups. Even if you plan to invite a professional, this knowledge will help you control the quality of the work performed.
Design and calculation of loads
The first and most important step is to draw up a detailed power supply diagram. You can't just buy a set of machines at random; it is necessary to clearly understand which consumers will be connected and what their total power is. Divide all appliances in the apartment into logical groups: lighting, sockets in living rooms, powerful consumers (hob, oven, air conditioner), as well as separate lines for the bathroom and kitchen.
For each group, calculate the current consumption. For example, for a socket group in living rooms, a 2.5 mm² cable and a 16 A circuit breaker are usually used. For lighting, a 1.5 mm² cable and a 10 A circuit breaker are sufficient. Pay special attention to powerful appliances: a hob may require a 6 mm² cable and a 32 A or 40 A circuit breaker. The total power of simultaneously switched on devices should not exceed the capacity of the input cable and the main circuit breaker.
When calculating, take into account the demand coefficient, since it is unlikely that all appliances in the apartment will operate simultaneously at full capacity. However, there must be a margin of safety. Use the formula P = U × I, where P is the power in Watts, U is the voltage (220 V), and I is the current in Amps. This will help you select protective devices with the correct ratings.
Selecting components for the electrical panel
The quality and reliability of the entire system directly depend on the selected components. The market offers many brands, from budget to premium, but saving on the “stuffing” of the shield is a risk that can be costly. The basis of your switchboard will be circuit breakers, residual current devices (RCDs) and differential circuit breakers.
Circuit breakers protect the cable from overload and short circuit. For a home network, the most commonly used characteristics are C (for active loads) and less often B (for lighting). An RCD protects a person from electric shock due to a leak, reacting to the difference in currents in the phase and neutral conductors. For an apartment, the optimal choice would be an RCD with a leakage current of 30 mA.
- 🔌 Introductory machine - the switch or circuit breaker that cuts off the power to the entire apartment must be two-pole.
- ⚡ Voltage relay - a device that protects equipment from power surges in the network is critically important in residential buildings.
- 🛡️ Diffavtomats - combined devices (automatic + RCD), saving space in the panel, but more expensive to replace.
You will also need quality comb (bus wiring) for connecting machines. Using homemade jumpers from wire scraps increases the risk of poor contact and overheating. To assemble a shield, choose modular equipment from one manufacturer, since different brands may have different seat geometry and contact heights.
Why can't you mix machine brands?
Although standard DIN rails are universal, the height of the contacts and the design of the release mechanism may vary from manufacturer to manufacturer (e.g. ABB, Schneider, Legrand). This can cause the comb to not fit into the grooves or the contact to be unreliable, which will cause sparking and melting.
Layout and assembly of the shield
It is more convenient to assemble the shield on a table, rather than hanging it by securing the DIN rail to a temporary support. First install all the modular devices on the rail according to your design, but do not tighten the fasteners too tightly yet to be able to move them. The optimal order of elements from left to right: input circuit breaker or circuit breaker, voltage relay, RCD (or automatic circuit breakers), and then group circuit breakers.
To connect the machines, use a copper comb. It provides reliable contact and an aesthetic appearance. Cut the comb to the required length, clean the edges and insert into the contacts. If the comb does not match the pitch or number of teeth, you can use professionally made wire jumpers, but always with crimped tips.
⚠️ Attention: When using stranded wire for jumpers inside the shield, be sure to use NSHVI lugs. It is forbidden to clamp a “bare” stranded wire into a machine - it will become crumpled over time, the contact will weaken, and heating will begin.
Observe the color marking of the wires: phase wires - white, black or brown; zero - blue; grounding ones - yellow-green. Inside the shield, the wires should be laid neatly, the bundles should be tied together with cable ties, and the excess ends should be cut off. Chaos in the panel makes it difficult to maintain and troubleshoot in the future.
☑️ Shield assembly checklist
Connection diagrams: single-phase and three-phase
Most apartments use a single-phase 220V network, but in new buildings with electric stoves, three-phase 380V is often found. The circuit of a single-phase shield is relatively simple: the phase and zero come to the input circuit breaker, then to the voltage relay, after which the phase diverges into groups through RCDs or automatic circuit breakers, and the zero is connected to the corresponding zero bus.
In a three-phase circuit, it is important to distribute the load evenly across all three phases to avoid distortion. Three-pole or four-pole circuit breakers and RCDs are used here. Each phase serves its own consumer groups. For example, a kitchen is placed in the first phase, living rooms in the second, and bathrooms and air conditioners in the third.
| Parameter | Single-phase network | Three-phase network |
|---|---|---|
| Voltage | 220 V | 380 V |
| Number of wires | 3 (Phase, Zero, Ground) | 5 (3 Phases, Zero, Ground) |
| Introductory machine | 2-pole | 4-pole |
| Application | Old stock, apartments without electric stoves | New buildings, apartments with electric stoves |
When assembling a three-phase shield, it is critical not to mix up the phases and correctly connect the neutral conductor, since its break in a three-phase network leads to a voltage surge to 380V at consumers. Use cross modules for convenient distribution of zeros and phases along different lines.
Use self-adhesive labels for each wire on both sides. In a year, you won’t remember where the “Kitchen 2 Sockets” wire leads, and the tag will save you hours of searching.
Installation and connection in the apartment
After assembling the shield on the table, the stage of installing it in a niche begins. Secure the switchboard body to the wall, bring all cable routes inside. Before connecting, check again that the markings on the machines and cables match. First of all, the neutral and grounding buses are connected, then the phase groups.
Strip the insulation from the wires carefully, without damaging the core. The stripping length should be such that no insulation gets into the contact group, but there is no bare wire left outside. Tighten terminals to the manufacturer's recommended torque, using a torque screwdriver if possible. Poor contact is the main cause of fires.
After connecting all lines, perform a visual inspection. Make sure that no wires are pinched by the switchboard door and that all elements are level. Before applying voltage, turn off all outgoing circuit breakers. Turn on the input circuit breaker and check the presence of voltage at the input of the RCD and the circuit breakers.
⚠️ Attention: Before turning on for the first time, be sure to “ring” the circuit with a multimeter to ensure there is no short circuit between phase and zero, as well as between phase and ground. Turning the machine on “short” can lead to an arc explosion.
System check and testing
The final stage is testing the assembled shield. Turn on the group line machines in sequence. When you turn on each machine, check whether voltage appears in the corresponding outlets. Pay special attention to checking the RCD: each device has a “Test” button. When pressed, the RCD should turn off instantly.
Check the operation of the voltage relay. If you have the ability to safely simulate a power surge (or if the device has threshold settings), make sure it handles emergency situations. It is also useful to load each line with a powerful device (for example, a hair dryer or a fan heater) and check whether the contacts in the shield get hot after 15-20 minutes of operation.
Regularly checking (once a month) the “Test” button on the RCD is the only way to make sure that the protection mechanism has not soured and will save lives at a critical moment.
If all tests are successful, close the shield plastron and stick the final designations on the modules. The electrical panel is assembled and ready for use. Remember that any modifications in the future should be carried out only with the input machine completely turned off.
How often do you need to stretch the contacts in the shield?
Modern modular machines and high-quality tips do not require regular broaching if they were tightened correctly during installation. However, 1-2 years after installation, it is recommended to carry out a preventive inspection and, if necessary, tighten the contacts, since copper tends to “flow” under load and temperature expansion.
Is it possible to use a machine with characteristic B instead of C?
Yes, it is possible, and even better for lines with sensitive electronics, since the type B circuit breaker responds faster in the event of a short circuit. However, if there are motors on the line (refrigerator, pump, air conditioner) with large starting currents, the type B machine may falsely trip when the device is turned on.
Why do you need a separate machine for the refrigerator?
Separating the refrigerator into a separate group (often not protected by an RCD or to a separate RCD) allows you to turn off the electricity in the entire apartment (for example, when going on vacation) without defrosting food. This also makes troubleshooting easier if the refrigerator is causing interference or leaks.