How many modules are there in plastic wall-mounted electrical panels: a complete selection guide for car enthusiasts

An electrical panel is not just a box with automatic machines, but the heart of the electrical system your garage, workshop or even home. For car enthusiasts who independently service their car, install an alarm system or connect a welding machine, the correct choice of shield becomes critical. Plastic wall-mounted electrical panels are popular due to their lightness, corrosion resistance and ease of installation. But how to understand them modular system? How many machines will fit there? And why is the shield on 12 modules may be cramped, but 24 - half empty?

In this article we will analyze in detail what types of plastic electrical panels there are according to the number of modules - from compact 6-module for minimalistic schemes to large ones 72-module for complex systems. You will learn how to calculate the required number of places for automatic machines, RCDs and other devices, as well as what brands (IEK, ABB, Legrand) offer the best solutions for car enthusiasts. Plus - practical installation tips and common mistakes that lead to overheating or lack of space.

If you have ever encountered a situation where there is not enough space in the panel for another machine, or vice versa - half the space is occupied by empty DIN rails, this article will help you avoid such problems. We will not delve into GOSTs (although we will mention the key requirements), but will focus on practical application: which panels are suitable for a garage with a welding station, and which ones are suitable for a summer house with a minimum set of sockets.

What is a “module” in an electrical panel and how to count it

Term "module" in the context of electrical panels, denotes a standard location on DIN railoccupied by one single-pole circuit breaker. The width of such a module is 17.5 mm (according to standard DIN EN 50022). This is a universal unit of measurement that allows you to quickly estimate how many devices will fit in the shield.

However, not all devices occupy the same number of modules. For example:

• 🔌 Single-pole circuit breaker (for example, IEK BA47-29) — 1 module.
• 🔌 Two-pole machine — 2 modules (width 35 mm).
• 🔌 RCD (residual current device) - from 2 to 4 modules depending on the model.
• 🔌 Differential automatic — 2 modules (combines automatic device + RCD).
• 🔌 Electricity meter (for example, Mercury 201) - 6–8 modules.
• 🔌 Voltage relay (for example, UBK-11) - 2–3 modules.

It is important to understand that nominal number of shield modules (for example, 12 or 24) is total capacity of DIN rails, not the number of machines. If you plan to install the meter inside the shield, it can take up to half the space! Also don't forget about stock: at least 20% of the modules must remain free for future modifications (additional socket, new consumer, etc.).

Plastic mounted electrical panels: standard sizes by module

Plastic shields are available in a wide range of sizes - from 6 to 72 modules. Below is a table with the most common options and their typical use for car enthusiasts.

Number of modules	Dimensions (H×W×D), mm	Typical Application	Example devices inside
6–8	200×250×120	Minimalistic schemes: country toilet, street lighting, temporary supply to the garage.	1–2 automatic machines + 1 RCD.
12–16	300×300×120	Garage with 1-2 outlets, lighting and small welding machine.	3–4 automatic machines + 1 RCD + voltage relay.
24	400×350×120	Full garage with compressor, machines, alarm system.	6–8 automatic machines + 2 RCDs + meter + terminal blocks.
36	500×450×150	Workshop with 3-phase power supply, several powerful consumers.	10–12 automatic machines + 3 RCDs + meter + phase control relay.
48–72	600×600×180	Large objects: car service center, house with garage, complex circuits with backup lines.	15+ machines + several RCDs + meters + smart home systems.

Please note: shield depth (the last parameter in dimensions) varies from 100 to 180 mm. For a garage with a large number of cables, it is better to choose deeper panels (from 150 mm) to avoid overheating and conveniently lay the wires.

Features of plastic shields

Plastic hinged panels have several key advantages over metal ones:

• ⚡ Lightness: the weight of a shield for 24 modules is only 2–3 kg (versus 8–10 kg for a metal one).
• ⚡ Corrosion resistance: do not rust, suitable for wet rooms (with protection class IP44 and above).
• ⚡ Easy to install: mounted on dowels or self-tapping screws, do not require grounding of the housing.
• ⚡ Price: 1.5–2 times cheaper than metal analogues.

However, there are also disadvantages:

• ⚠️ Low mechanical strength: Plastic may crack if subjected to strong impact.
• ⚠️ Limited heat resistance: some models can only withstand heating up to 60°C (critical for panels next to boilers or stoves).
• ⚠️ Less fire safety: metal shields provide better protection against fire during a short circuit.

How to calculate the number of modules for your garage

To avoid making a mistake with your choice, use a simple calculation method:

1. Make a list of all consumers (sockets, lighting, welding machine, compressor, alarm, etc.).
2. Break them into groups by type of protection (for example, sockets - on an RCD, lighting - on a regular machine).
3. Choose automation for each group (see table below).
4. Add up the number of modules all devices.
5. Add 20–30% reserve for future improvements.

Calculation example for a typical garage:

Consumer	Type of protection	Number of modules
Lighting (3 lines)	Automatic 10A (1P)	3 × 1 = 3
Sockets (4 pcs.)	Automatic 16A (1P) + RCD 25A	4 × 1 + 2 = 6
Welding machine	Automatic 25A (1P)	1
Compressor	Automatic 20A (1P)	1
Electricity meter	Mercury 201	6
Total without stock		17
+ 30% stock		≈ 22

Conclusion: for such a garage you need a shield 24 modules. If you plan to add, for example, a heating system or charging for an electric car in the future, take 36-module.

Typical mistakes when choosing

⚠️ Attention: Many car enthusiasts forget that three-phase machines occupy 3–4 modules (for example, ABB S203 - 3 modules), not 1! This results in a lack of space in the shield.

Other common mistakes:

• 🔌 Ignoring counter width (especially if it is installed inside the shield).
• 🔌 Buying a back-to-back shield without stock—later, when adding a new machine gun, you have to change the shield completely.
• 🔌 Unaccounted place for terminal blocks and tires (they also take 1–2 modules).
• 🔌 Shield selection with thin wallsthat break when tightening cable ties.

Review of popular brands: who offers the best plastic shields

There are dozens of brands on the market, but for car enthusiasts the most interesting are those that combine quality, price and ease of installation. Let's look at the top 5 manufacturers:

1. IEK (Russia/China)

Budget option with a wide range. Shields series KMPn (mounted) and ShchRN (distribution) are suitable for garages with low protection requirements. Pros:

• ✅ Price from 800 rub. for a 12-module shield.
• ✅Easy to find at any electrical store.
• ✅ Compatible with vending machines IEK and KEAZ.

Cons: thin plastic, poor dust protection (IP40).

2. Legrand (France)

Premium segment. Series Plexo - one of the most reliable for garages. Features:

• ✅ Protection class IP55 (suitable for wet areas).
• ✅ Heat resistance up to 85°C.
• ✅ Modular system with expandability.

Price: from 3,500 rub. for a 24-module shield.

3. ABB (Sweden/Germany)

Optimal price/quality ratio. Series Mistral popular among electricians. Pros:

• ✅ Durable plastic (shockproof ABS).
• ✅ Convenient DIN rail fastening system.
• ✅ Compatible with vending machines ABB S200.

Price: from 2,200 rub. for a 16-module shield.

4. Schneider Electric (France)

Shields series Kaedra and Prisma suitable for complex circuits. Features:

• ✅ Possibility of installing meters inside the shield.
• ✅ Vandalism protection (locking door).
• ✅ Wide selection of accessories (cable holders, marking stickers).

Price: from 4,000 rub. for a 36-module shield.

5. TDM (Russia)

Budget alternative IEK with the best quality plastic. Series SSP (plastic shields). Pros:

• ✅ Price is 10–15% lower than IEK.
• ✅ Protection class IP44 as standard.
• ✅ Zero tires included.

Price: from 900 rub. for a 12-module shield.

How to distinguish a fake?

Original shields Legrand and ABB have:

- Clear marking with logo and article number on the inside of the door.

- Smooth plastic edges without burrs.

- A set of documentation (passport, certificate).

- Packaging with a hologram (with Legrand).

Installation of a plastic electrical panel: step-by-step instructions

Installing a hinged panel in a garage or workshop consists of several stages. Let's consider the process using the example of a shield on 24 modules (ABB Mistral).

1. Preparation of tools and materials

You will need:

• 🔧 Drill or hammer drill (for mounting to the wall).
• 🔧 Phillips and flat screwdriver.
• 🔧 Wire cutters and stripper for stripping wires.
• 🔧 Level (so that the shield hangs evenly).
• 🔧 Dowels or screws (depending on the wall material).
• 🔧 DIN rails (if not included).
• 🔧 Terminal blocks and zero bus.

2. Marking and fastening the shield

Optimal installation height - 1.4–1.7 m from the floor (to make it convenient to turn on the machines). Attach the shield to the wall, level it and mark the mounting points. For a concrete wall, use dowels 6×40 mm, for wood - self-tapping screws 4×30 mm.

⚠️ Attention: If the shield is installed in a garage with metal walls (for example, made of corrugated sheets), use screws for metal with press washer and rubber gaskets for tightness.

3. Installation of DIN rails and modular devices

Procedure:

1. Secure the DIN rails inside the panel (they are secured with latches or screws).
2. Install machines, RCDs and other devices from left to right, starting with the introductory machine.
3. Connect zero bus and ground bus (they are usually attached to the bottom of the shield).
4. Separate the wires into groups and arrange them neatly using cable ties.

4. Connecting wires

Observe the color coding:

• 🔴 Phase (L) - brown, red or black wire.
• 🔵 Zero (N) - blue or light blue.
• 🟢 Earth (PE) - yellow-green.

Connect wires to machines from top to bottom (according to standard PUE 3.1.6). After connecting, check the reliability of the contacts - pull each wire: it should not jump out of the terminal.

5. Checking and commissioning

Before applying voltage:

• Check all lines with a multimeter for short circuit.
• Make sure all machines are turned off.
• Turn on the input machine and test each line one by one.

Common problems with plastic shields and how to avoid them

Even high-quality plastic shields can cause trouble if some nuances are not taken into account. Let's look at typical problems and ways to solve them.

1. Shield overheating

Reasons:

• 🔥 Laying the wires too tightly (ventilation is disrupted).
• 🔥 Powerful consumers (welder, heater) are connected through weak machines.
• 🔥 The shield is installed next to the heat source (stove, boiler).

Solution:

• ✅ Use shields with ventilation holes (for example, Legrand Plexo).
• ✅ Install cooling fan (there are special models for shields).
• ✅ Divide powerful consumers into separate lines with machines of the corresponding denomination.

2. Melting plastic

If the shield body begins to melt, this is a sign:

• 🔥 Bad contact in the terminals (sparking → heating).
• 🔥 Overload by current (the machine does not work, the wires get hot).
• 🔥 Low quality plastic (cheap shields made from recycled materials).

⚠️ Attention: If the plastic has darkened or become deformed, turn off the power immediately and check all connections! Melting may cause a fire.

3. Lack of space for new devices

If the shield is filled to capacity and you need to add another machine, there are several options:

• 🔧 Replace the shield with a larger one (for example, from 12 to 24 modules).
• 🔧 Use double tier DIN rails (allow you to double the number of modules in the same housing).
• 🔧 Install modular devices of smaller width (for example, machines ABB S290 by 0.5 module).
• 🔧 Move the meter or RCD to a separate box.

4. Ingress of dust and moisture

In the garage, the shield is often exposed to dust, dirt and condensation. To protect your equipment:

• 🌧️ Choose shields with a protection class IP54 and above.
• 🌧️ Install sealing gum on the door (sold separately).
• 🌧️ Regularly wipe the shield body with a dry cloth.
• 🌧️ If the shield is on the street, use sealed casing.

FAQ: Answers to frequently asked questions

Is it possible to install a plastic shield on the street?

Yes, but only if it has a protection class IP55 or IP65 (for example, Legrand Plexo 3 or ABB Mistral 65). Also recommended:

• Install the shield under a canopy or in a sealed box.
• Use anti-vandal locks on the door.
• Lay the cable in a corrugated IP68.

How much does a plastic electrical panel for 24 modules cost?

The price depends on the brand and configuration:

• IEK KMPn — from 1,200 rub.
• TDM SChP — from 1,500 rub.
• ABB Mistral — from 2,500 rub.
• Legrand Plexo — from 3,800 rub.

The price does not include machines, RCDs and meters!

Which shield to choose for a garage with a welding machine?

Minimum requirements:

• 🔌 24–36 modules (to place machines for welders, sockets, lighting).
• 🔌 Protection class IP54 (protected from dust and splashes).
• 🔌 Heat resistance not lower than 85°C.
• 🔌 Availability input circuit breaker for 40–63A (depending on the power of the welder).

Recommended models: ABB Mistral 65, Schneider Electric Kaedra.

Is it possible to paint a plastic electrical panel?

Yes, but with reservations:

• Use acrylic paint (not oil!).
• Before painting, degrease the surface with alcohol.
• Don't paint ventilation holes and seals.
• After painting, allow the shield to dry for 24 hours before installing.

It is better to choose shields of the desired color immediately (for example, Legrand offers grey, white and black options).

What to do if there are not enough DIN rails in the panel?

There are several solutions:

1. Buy more additional DIN rails (sold separately, secured with self-tapping screws).
2. Use two-tier slats (double the number of modules).
3. Replace the shield with a larger one (for example, from 12 to 24 modules).
4. Move some of the devices (meter, RCD) to separate box.

If the problem is lack of space for wires, install cable organizers (for example, Legrand DLP).