DIY electrical panel assembly

Recommendation points

• We design an electrical panel
• Consumer accounting, group creation
• We make an electrical panel diagram
• Selection of components and accessories for the electrical panel
• Shield body
• Modular device specification
• Supporting materials
• Assembling and disconnecting the switchboard
• 1. Assembly and preliminary assembly of the box
• 2. Prepare wires
• 3. Reinstalling the shield
• 4. Arrangement of modular devices on a DIN rail
• 5. Commutation
• 6. Input connection
• 7. Final stage

This is a step-by-step practical instruction for those who want to learn how to assemble and switch a switchboard on their own. In the article, we tried to describe in detail all the key operations, paying special attention to the nuances that may be unknown to amateur electricians.

The assembly and disconnection of input distribution devices (ASU) is a multi-stage type of work, where each stage is extremely important, where there are no trifles. The shield must turn out to be safe and convenient for use, all its elements, combined into a system, must regularly perform the functions assigned to them:

• energy control;
• consumer and chain management;
• provision of selectively triggered protection.

You can organize an electrical panel yourself, but for this, the home craftsman needs to have electrical installation skills above the minimum level. For the design of the ASP and the selection of components, it will not be superfluous to understand the processes and know the rules. Next, we will consider the assembly of electrical panels using the example of fairly branched systems in order to cover a wider range of issues..

We design an electrical panel

For a layman, this is best done when all the wires have already been laid and all the circuits have been accounted for. At the development stage, we must create working drawings for ourselves, according to which subsequent work will be carried out, as well as found suitable specifications for components and accessories.

Consumer accounting, group creation

You need to start by compiling a complete list of consumers, if it was not done during the installation of the wiring. This will include not an iron and not a sconce in the hallway, but each wire coming to the shield, which must be recorded and indicated by a number.

The power supply systems for residential premises are carried out according to the same principles, therefore they are similar to each other. The power sockets of each room are powered separately and the lighting of the rooms is separately powered. Some household appliances are not connected to junction boxes, their wires go directly to the switchboard. This is not always due to their increased power, like an electric stove, for example. Isolation may be the result of increased protection requirements (the boiler must be connected through a very sensitive RCD), or the need to turn off the device locally (air conditioner for maintenance).

So, here’s a typical list for a modern three-room apartment:

1. Bedroom sockets.
2. Living room sockets.
3. Children’s sockets.
4. WC sockets.
5. Kitchen sockets.
6. 6. Sockets corridor + hallway.
7. Washer.
8. Boiler.
9. Air conditioning.
10. Electric stove.
11. Bedroom light.
12. Living room light.
13. Children’s light.
14. Light kitchen + bathroom.
15. Light corridor + hallway + balcony.

Of course, if you put each circuit on its own machine and run it through an RCD, it will be both more reliable and more convenient. But the issues of compactness and economy are also important. We can combine some of the circuits listed above if the load is moderate, and separate automation is not needed. For example, points 1 and 2, combinations 11 + 12 + 13 and 14 + 15 are also possible.

Attention! To disconnect low-current consumers (TV, telephone, Internet, security), you must use a separate box.

After combining, we transform the list into a simple table, where we then enter data on the ratings of machines and RCDs.

We make an electrical panel diagram

All modern switchboards are designed for mounting unified modular devices. A module is considered to be an 18 mm product that is mounted on a DIN rail. This is the so-called one “place”. Note that apart from single devices, there are double and triple devices. We need to depict a schematic diagram of the electrical panel assembly, where all modular devices will be indicated.

Scheme using difavtomats: 1 – introductory machine; 2 – counter; 3 – zero block; 4 – grounding block; 5-9 – differential automata; 10 – lighting machine

Scheme using an RCD: 1 – introductory machine; 2 – counter; 3 – fire-prevention RCD; 4 – common zero bus; 5,6,12 – lighting machines; 7 – RCD for consumers 2,3,4; 8,9,10 – machines for consumers 2,3,4; 11 – additional zero bus; 13 – differential machine; 14 – RCD for circuits 5,6,7; 15,16,17 – machines for consumers 5,6,7; 18 – additional zero bus; 19 – grounding bus (conductors from lighting can also come here)

Please note that you can count the number of seats and form rows (for example, it would be logical to raise machine 12 to the second row, to devices 5 and 6).

Selection of components and accessories for the electrical panel

Shield body

The first step is to buy the correct box. For an apartment, the built-in option will be optimal, as the most ergonomic. Metal or plastic – it doesn’t matter, the main thing is the quality of work. The most convenient and practical are models from leading manufacturers from Europe. If the apartment is densely electrified, and there are a lot of wires, then a shield with removable walls (back, top, bottom) will be an indisputable advantage for the installer. On some models, DIN rails can also be quickly removed or pushed back.

Attention! An important parameter of the box is the number of installation places. Choose a model with a stock of several modular locations.

Modular device specification

We select circuit breakers, RCDs, differential circuit breakers, contactors, various relays. Also, modular sockets, buses, transformers, power supplies, monitoring and control devices can be installed on the rail.

All devices are selected according to several key parameters:

• rated working current;
• response speed (automatic machines);
• tripping current (for RCDs, automatic devices, difavtomats);
• permissible operating frequency (contactor).

These characteristics are calculated for each connected circuit separately. It is very important here that the system is balanced. For example, it is impossible for a weak consumer to install a too powerful machine that cannot normally protect the wiring from overload. So, for lighting, machines with a rated current of 6, 10 amperes are used, for ordinary power outlets a 16 A device is required. A water heater, a washing machine, and an air conditioner can also be powered through 16-amp machines. A powerful electric stove will require a protective device of 20-25 amperes. The input will need a two-pole automatic device for 32-60 A, depending on the total power consumption of the facility.

The chains should be disconnected independently of each other and preferably in order from branch to trunk. This is the selectivity, which is necessary so that in an emergency situation, the entire object is not de-energized, and it is easier to find the fault..

For this, the machines have a so-called “setting” in response time (in electrical engineering, there are options for settings in frequency, power, voltage). For example, if there are several 25 amp circuit breakers in the circuit, then a device is put on the consumer, which turns off in 0.1 seconds, and on the higher machine – 0.5 seconds.

The rated current of the RCD is considered in conjunction with the operating current of the subordinate machines. It must be higher so that, if problems arise, the machine can first turn off and the expensive RCD is not damaged. Residual current devices for 20 and 25 amperes are installed for 16-amp circuit breakers. With an automatic for a 25 A cooker, a 40 Amp RCD is used.

The RCD trip current will characterize how sensitive it is. Devices for quick protection of a person are distinguished, for example, a 10 mA RCD is installed for:

• bathroom sockets;
• water heater;
• washing machine;
• sockets in the nursery.

However, in some cases, such devices can give false alarms, therefore 30 mA RCDs are quite popular (kitchen sockets, underfloor heating, etc.). To ensure fire safety, models with an actuation current of 100-300 milliamperes are used..

Supporting materials

A DIN rail is usually included in the kit, but even branded distribution boards are not always equipped with good tires. Therefore, they have to be collected separately. This should be a strip with a sufficient number of holes, always with a plastic protector for mounting on a rail or on the walls of the box. Ideally, if the live parts of the busbars are covered with a cover. Requires a bus for neutral (zero) and ground.

If, according to the scheme, it is supposed to connect more than two conductors to one modular device, then it is worth purchasing terminal blocks in order to make the branching reliably and accurately. They can also be designed for DIN rail mounting.

To transfer voltage between modular devices (RCDs, automatic devices) in the same row, it is convenient to use insulated combs. They provide good contact, withstand heavy loads, save time, and improve the ergonomics of the assembled switchboard. Combs are available in different lengths and cut as needed (also purchase side plugs).

To connect multi-pole automation, there are combs for several independent rows.

Between the rows of modular devices, the phase will have to be distributed with a piece of wire, then its stripped edge must be squeezed in the tip. Products with a length of a centimeter or more are better suited. To clamp two conductors in one machine, it is worth using double lugs. There are models for 3 wires, for conductors of different cross-sections.

Assembling and disconnecting the switchboard

Before starting work, we recommend arranging emergency lighting for the working area (in extreme cases, when reconnecting, use a headlamp). Use a table where you can lay out tools and accessories. Make some brackets on the wall to temporarily tie the wires that are not yet connected. In an easy-to-view place, hang the electrical panel assembly diagram. Check the completeness of the systems. Disconnect the input cable.

1. Assembly and preliminary assembly of the box

The flap housing should be prepared:

• remove the plugs on the walls of the box (sometimes you have to cut out additional holes for entering wires);
• screw on DIN rails;
• we install on the walls of the neutral and ground bus;
• remove the door (if any);
• connect the mounting brackets.

The built-in drawer can now be temporarily secured in place by checking the quality of the created niche. It is immediately removed so that it is convenient to deal with the wires, in addition, many professional electricians prefer to do part of the work at the workbench (you can put the automation, open the necessary jumpers).

2. Prepare wires

First you need to roughly adjust them in length. This is especially true if there is no cavity in the wall where you can place excess wire (for example, if a niche is in brickwork). But you need a margin so that you can easily reach the most distant circuit breaker or bus.

Attention! Sometimes, if there are a lot of consumers, it makes sense to lead some of the conductors into the box from above, and some from below. Therefore, group them according to this criterion and collect them in bunches..

The outer insulation is now removed from the wiring cables. It is better to do this with a special tool that does not damage the primary insulation of the conductors..

It is necessary to clean it so far that at the entrance to the box the wire still remains with external insulation. Ideally, the corrugated channel (or pipe) should also enter..

Attention! When the outer insulation is removed, the marking is also lost (often the wires are simply signed with a marker on top during installation). Therefore, we recommend marking the conductors at the same time as cleaning. It is convenient to use masking tape, on which you can make any notes.

3. Reinstalling the shield

We lay all the conductors and the lead-in cable inside. It makes sense to level the wires in one layer, it is advisable to take into account the arrangement of the machines (see the diagram) to which they will be connected.

4. Arrangement of modular devices on a DIN rail

We produce according to the scheme, we strictly observe the correspondence of the denominations. Usually, the RCD is first fixed, and immediately after it – its machines, at the end there are independent circuit breakers and other modular devices.

It is not necessary to install all the automatics at once, some craftsmen like to power the RCD and the automatics one by one, as they are attached to the rail. At the same stage, the meter is mounted, if its place is in the shield.

5. Commutation

We connect the conductors of each circuit or a specific consumer to our machines and buses one by one. There are several important points here:

• we work in order, for example, from right to left;
• we bring the core to the fixation point and cut off the excess;
• we lay the wires in the shield horizontally and vertically, turns – only at right angles;
• if there is not enough space, or it is not possible to bring wires from different sides of the box – you can go through the wires behind the DIN rail.
• we clean the ends of the wires from the main insulation by about 1 centimeter (we use a special tool);
• be sure to put on tips on soft veins;
• we make the ends under the clamp of the machine and tighten the terminal tightly;
• we supply voltage to the machine from above, and connect the conductor from below (although most devices are bilateral, this is a generally accepted standard);
• tugging the wire with our hands, we check the reliability of fixation, while we pay attention that copper does not protrude above the machines, but the insulation is not clamped either;
• we collect the bundles of wires together with plastic ties and place them behind the rail.

We distribute phase and zero between modular devices. Non-professionals usually have difficulties with RCD switching, how to do this can be seen in the shield diagram.

The main transfer in one row can be done with contact combs; in the absence of such, electricians sometimes use homemade jumpers. These should be rigid wires with a cross section of 4-6 squares.

6. Input connection

The lead-in cable is clamped on the main machine (phase and zero), and the grounding conductor goes directly to the bus. From the machine, the phase and zero go either to the counter, or are already distributed according to the scheme.

7. Final stage

If the wiring is ready, the consumers are connected and the wiring accessories are in place, then you can alternately apply the load to the individual lines. Each RCD is tested by pressing the corresponding button (the voltage in the controlled circuit must be turned off). Power the entire system as long as there is no problem. Now it remains to mark the automation, attach a circuit to the door, install the covers on the flap body.

Competent and accurate assembly of electrical panels is the key to the durable operation of all wiring. But it should be noted that you cannot save on components. High-quality automation from well-known manufacturers will avoid costly accidents and can save lives.