If, when you turn on the washing machine in the garage, the machine in the switchboard knocks out, and the wires heat up to the characteristic smell of plastic, the problem is not in the equipment, but in incorrectly assembled distribution board. The switchboard assembled with circuit breakers must correspond to the total network load, have a current reserve of 25-30% and properly separated groups of consumers. For example, for a garage with a welding machine (25A), lighting (10A) and sockets (16A), you need a switchboard for at least 6 modules with an automatic input C40 and a 40mA RCD - otherwise, every start of the compressor will turn off the light.

In 80% of cases, “homemade” switchboards are assembled with errors: they install circuit breakers with a smaller rating than the cable cross-section, ignore selectivity, or connect a phase to the zero bus. The consequences range from constant false alarms to fire. This article will help you avoid common mistakes: let’s look at how to choose a shield by the number of modules, which machines to install on different groups of consumers, how to properly connect RCDs and automatic circuit breakers, and we will also show diagrams for the home, garage and workshop.

1. Types of panels assembled with machines: which one to choose for your home, garage or cottage

Shields are divided into three categories according to their purpose, and an error in selection leads to overheating of the contacts or the inability to connect new lines. Let's look at the key differences:

  • 🏠 Input distribution boards (IDU) - for the entire electrical network of the house. There is space for a counter, an input machine (up to 100A) and up to 72 modules for group automation. Suitable for cottages with three-phase input.
  • 🚗 Garage panels — compact (12-24 modules), with enhanced dust protection (IP54) and moisture. They are often equipped with a socket for connecting a tool.
  • ⚡ Accounting and distribution boards (SCHUR) - for apartments. Includes a sealable compartment for the meter and machines for 10-20 modules.

For a car garage, the optimal shield is 18-24 modules with separate lines to:

  • 🔌 Sockets (16A, cable 2.5 mm²)
  • 💡 Lighting (10A, cable 1.5 mm²)
  • 🔥 Welding station or compressor (25A, 4 mm² cable)
  • 🚪 Electric gates (10A, with RCD)
⚠️ Attention: If there is an old switchboard in the garage SGR-11 (Soviet model), it cannot be modernized by adding machine guns - the case is not designed for modern modules. Replacement is required!

2. How to calculate the number of modules in a panel: formula and examples

One module = 17.5 mm width. Automatic machines occupy 1 module, RCD - 2-4 modules, counter - 6-8 modules. Calculation formula:

Number of modules = (Number of automatic devices × 1) + (Number of RCDs × 2) + (Number of automatic devices × 2) + 10% (stock)

Example for a garage:

  • Introductory machine C32 — 1 module
  • RCD 40mA - 2 modules
  • Circuit breakers for sockets (2 pcs.) - 2 modules
  • Automatic lighting - 1 module
  • Automatic compressor - 1 module
  • Total: 7 + 1 (stock) = 8 modules (minimum). It is better to take a shield with 12 modules for future expansion.
📊 What shield do you have installed now?
Soviet (type SGR-11)
Plastic box without modules
Modular for 12-24 seats
Shield with machine guns and RCDs

3. Connection diagrams: single-phase and three-phase networks

An error in the connection diagram leads to the fact that in the event of a short circuit in one line, the entire panel is switched off. Below are proven schemes for different cases.

Single-phase network (220V)

Suitable for garages and houses with loads up to 10 kW. Connection order:

  1. Input cable → introductory machine (nominal value as agreed with energy sales).
  2. After the machine → counter (if the shield is registered).
  3. From the counter the phase goes to RCD, and zero - to the zero bus.
  4. With an RCD, the phase is separated to group machines.

Three-phase network (380V)

For workshops with equipment (lathe, welding machine). Features:

  • 🔹 Introductory machine 3P (three-pole).
  • 🔹 There must be an RCD four-pole.
  • 🔹 The phases are distributed evenly: for example, sockets - on phase A, lighting - on B, machine - on C.
Network type Introductory machine RCD Input cable cross-section
Single-phase (up to 5 kW) C25 40mA, 2P 3×6 mm²
Single-phase (5-10 kW) C40 63mA, 2P 3×10 mm²
Three-phase (up to 15 kW) C50, 3P 100mA, 4P 5×6 mm²
⚠️ Attention: In three-phase switchboards prohibited combining neutral wires of different groups onto one bus before the RCD - this will lead to false alarms!

4. TOP 5 shields assembled with machine guns: rating for 2026

The choice of shield depends on the budget and tasks. Below are proven models taking into account the price/quality ratio:

  • 🥇 IEK MICRON (IKM-12N) — 12 modules, IP40, DIN rail and zero bus included. Optimal for a garage (price ~2500 rubles).
  • 🥈 ABB Mistral 65 (24 modules) - metal body, IP54, removable walls for easy installation. Suitable for a home with three-phase input (~8000 rub.).
  • 🥉 Schneider Electric Kaedra (KNX-18) — 18 modules, transparent door, sealable. The best choice for an apartment (~5000 rub.).
  • 4️⃣ Legrand Plexo (36 modules) — premium class, modular system, compatible with smart meters (~ RUB 12,000).
  • 5️⃣ DEKraft ShRN-P-24 — budget plastic shield for 24 modules with an RCD included (~3500 RUR).
How to distinguish a fake ABB or Schneider shield?

The original shields have:

- Serial number on the case and packaging (the same).

- The logo is engraved, not pasted on.

- The kit includes a passport with a hologram.

- Plastic does not smell of chemicals (counterfeits have a strong smell).

5. Step-by-step instructions for installation and connection

Installation of the switchboard requires compliance with the PUE (Electrical Installation Rules). Below is the algorithm for a single-phase network:

Make sure that the input cable is disconnected (check with an indicator)|Ground the panel housing (for metal models)|Mark the machines by groups (for example, “Garage sockets”)|Check the integrity of the cable insulation-->

  1. Mounting the shield. Mark holes on the wall for dowels (for concrete - 6×40 mm). The shield should hang at a height of 1.4-1.7 m from the floor.
  2. Installation of DIN rails. Attach the slats to the panel body (included in the kit). The distance between the slats is at least 125 mm for ventilation.
  3. Installation of automatic machines. Attach the machines to the rail, starting with the introductory one. Use comb tire for connecting machines (it is forbidden to twist the wires!).
  4. Connecting wires. Phase wires (brown/red) - to the machines, neutral (blue) - to the zero bus, grounding (yellow-green) - to the ground bus.
  5. Check. Turn on the input circuit breaker and test each line one by one with a multimeter (voltage should be 220V ±10%).

For a three-phase switchboard additionally:

  • 🔌 Phases A, B, C must be balanced by load (difference no more than 20%).
  • 🔌 Zero wire with a cross-section no less than the introductory phase.
💡

If you hear a cracking sound when you turn on the machine, this is a sign of poor contact. Immediately turn off the power and tighten the terminals!

6. Common mistakes and how to avoid them

Even experienced electricians make mistakes when assembling panels. Here are the most critical ones:

  • 🔥 The machine is larger than the cable cross-section. For example, a machine is installed on a 1.5 mm² cable C25. Consequence: the wire overheats, but the machine does not work. Rule: the machine's rating must be less, than the long permissible current of the cable.
  • ⚡ No RCD for wet rooms. An RCD is a must in a garage or workshop - it will save you from electric shock if the insulation breaks down.
  • 🛠️ Using twists instead of terminals. The twists oxidize and heat up. Use Wago terminals or sleeves.
  • 🔌 Connecting zero to ground. This is a gross violation of the PUE, leading to the activation of the RCD and the risk of fire.
💡

The main rule of selectivity: the introductory machine should be 1-2 steps higher than the group one. For example, if the sockets are C16, then the input should be C25 or C32.

7. Shield maintenance: inspection and prevention

The shield assembled with the machines requires regular maintenance - at least once a year. Neglect leads to the contacts oxidizing, and the machines “stick” and stop working. Test plan:

  1. External inspection. Check for any melting on the body, foreign odors (burnt plastic), or cracks.
  2. Checking machines. Turn off the power and manually turn on/off each machine - it should click clearly, without jamming.
  3. Tightening contacts. Tighten all terminals of the machines and busbars with a screwdriver (tightening torque - 2.5 Nm).
  4. RCD testing. Press the "Test" button on the RCD - it should turn off. If not, replacement is required.
  5. Voltage measurement. Using a multimeter, check the voltage on each line (should be 220V ±5%).
⚠️ Attention: If the machine sparks when the machine is turned off, this is a sign of worn contacts. Such a machine needs to be replaced, even if it is still “working”.

FAQ: Frequently asked questions about machine gun shields

Is it possible to place a shield in a garage on a wooden wall?

Yes, but subject to the rules:

  • The shield must be metal with IP54.
  • A sheet of asbestos or metal (40x40 cm) is attached to the wall under the shield.
  • The input cable is laid in a metal hose.
Which machine to put on the welding machine (200A)?

The welder requires a separate machine C50 or C63 (depending on the maximum current of the device) and cable cross-section 10-16 mm². Connect via a separate line with a 100mA RCD.

What to do if the shield gets hot?

Causes and solutions:

  • 🔹 Poor contact — tighten the circuit breaker terminals.
  • 🔹 Overload — divide the lines or increase the rating of the machine (if the cable cross-section allows).
  • 🔹 Cheap slot machines - replace with ABB or Schneider Electric.
Do I need an RCD in a panel for a garage?

Definitely! The RCD protects against:

  • Electric shock due to insulation breakdown (for example, while being carried).
  • Fire due to current leakage on the equipment housing.

Minimum denomination for garage - 30mA.

Is it possible to assemble a shield yourself if you have no experience?

It’s better to entrust the assembly to an electrician, but if you decide to do it yourself:

  • Use ready-made shields (for example, IEK Micro).
  • Follow the wiring diagram without improvisations.
  • After installation, invite a specialist to check.