What machine to put on the refrigerator: calculations, schemes and 5 critical errors

A refrigerator in a garage or home workshop is not a luxury, but a necessity for the safety of food, drinks or even autochemistry. But to connect it “in a hurry” through the first outlet – means to risk both technology and security. Automatic switch (automatic switch) for the refrigerator should be selected taking into account its power, initiation currents and electrical wiring features. In this article, we will understand how not to make a mistake with the nominal value, whether it is necessary to put an ultrasound system, and why a cheap “Chinese” automatic machine for 16A can burn up on the first day of operation of the compressor.

Many car owners install refrigerators in garages to store perishable auto chemicals (for example, car owners). lithium-lubricant or sealant) and for summer picnics. Others connect them in home workshops or in dachas, where the power grid is not always designed for additional load. The main problem The refrigerator does not just consume energy, but does it cyclically, with peak loads when starting the compressor. If the machine is selected incorrectly, it will work on each turn on, or, worse, it will not work on a short circuit.

In this article, we will not talk about a “model” solution because there is no one. The value of the machine depends on:

• 🔌 Refrigerator power (100 to 800 watts)
• 📊 Like a compressor. (inverter or conventional)
• 🔋 Electrical wiring conditions (cable cross section, material lived)
• 🏠 Places of installation (garage, house, street boxing)

Ignoring at least one of these factors can lead to fire or failure of equipment. Next – step by step analysis with examples of calculations and schemes.

1. Refrigerator power: how to calculate the nominal value of the machine

The first thing you need to know is nominal capacity your fridge. It is listed in the device's passport or on the sticker at the back (look for the inscriptions). «Input Power», «Rated Power» plainly W). For example, the most popular models for garages (Indesit TLAA10, ATLANT MXM 1705) power ranges from 120 to 200 W, and large household (Samsung RB37J5240SA) Up to 400-600 watts.

But there's a catch: compressor at the time of start consumes 3-5 times more currentthan in the operating mode. So if your refrigerator has a capacity of 200 watts, then the peak load can reach 1000 watts! It's called trigger-currentIt must be taken into account when choosing a machine.

The formula is simple:

I = P / U

where:

• I - ampere current (A)
• P - wattage (W)
• U - network voltage (220 V for Russia)

Example: refrigerator ATLANT MXM 1705 (150 watts) at peak consumes 750 watts. Then:

I = 750 W / 220 V ≈ 3.4 A

But it's maximum current. For the reserve, the machine must be at least 25% more powerful:

A × 1.25 ≈ 4.25 A

The nearest standard denomination is 6A.. However, for garages with unstable voltage is better to take 10A.To avoid false positives.

2. Type of machine: which to choose for the refrigerator

Automatic switches are divided into three types of time-current characteristics:

• B - works when the current is exceeded by 3-5 times. Suitable for refrigerators with compressor.
• C - works at a 5-10-fold excess. Universal option, but may not save from weak overloads.
• D - withstands 10-20-fold jumps. Used for refrigerator Or powerful industrial models.

For most household and garage refrigerators, it is optimal. type-C. It will protect against short circuit and will not work every time the compressor is started.

Also pay attention to manufacturer. Cheap machines (IEK, EKF) often do not conform to the declared characteristics and may become stuck when overloaded. Recommended brands:

• 🔹 ABB (SH200 series)
• 🔹 Schneider Electric (Easy9)
• 🔹 Legrand (DX³)

3. Do I need an ultrasound for the refrigerator?

Protective shutdown device (RCD) It protects not from overload but from leakage For example, if the insulation of the cable is damaged or someone touches the bare wire. For the refrigerator in the garage, CCD necessarily For two reasons:

1. Humidity and condensation increase the risk of electric shock.
2. The metal body of the refrigerator may be energized when the insulation breaks.

The RCD should be a step higher than the machine. Examples:

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Attention: If the garage already has a general RCD for 100-300 mA (for example, at the input), Additional 10–30 mA RCD for the refrigerator is still necessary It will work faster and save lives when touched directly.

4. Connection schemes: how to properly connect the machine

There are three ways to connect the refrigerator in the garage or house:

1. Direct connection via automatic (most reliable option):

   Shields → Automatic (6-16A) → RCD (10-30mA) → Socket → Refrigerator

2. Connection via difaute (Automatic + RCD in one case):

   Shields → Difautomat (16A, 30mA) → Rosette → Refrigerator

3. Connection to common line (Not recommended, but possible if conditions are met):

   Shields → General machine (25A) → [Other appliances] → Socket → Refrigerator

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Attention: If you connect the refrigerator to the general, make sure that:

• 🔌 The machine is no more on the line. 16..
• 📊 The refrigerator is the only powerful device on this line (for example, it should not work with it). welding-stuff or compressor).
• 🔋 Wiring - copper, cross section at least 2.5 mm2.

Otherwise, you risk being left without light in the garage every time the refrigerator starts to freeze.

Check the cable cross-section (minimum 1.5 mm2 for copper, 2.5 mm2 for aluminum) |

Make sure the outlet is grounded |

Select a machine with a current reserve (minimum +25% to the calculated)|

Check the absence of twists and "bugs" in the wiring |

Install an RCD with a leakage current of 10–30 mA-->

5. 5 critical mistakes when choosing a refrigerator machine

Even experienced electricians sometimes make mistakes that lead to a breakdown of equipment or fire. That's what don't under no circumstances:

1. Ignore the initiating currents. If you put a 6A machine on a refrigerator with a peak load of 1500 W (≈6.8 A), it will work every time the compressor starts.
2. Use a Type D machine for a normal refrigerator. It will not protect against weak overloads, but it will miss dangerous jumps.
3. Connect the refrigerator through the extension cord without grounding. This violates the requirements of PUE and increases the risk of electric shock.
4. Saving on the RCD. Cheap models (IEK, TDM) may not work in the event of leakage, especially in a wet environment.
5. Connect the refrigerator to a line with an old aluminum cable. Aluminum is oxidized, warmed and can cause a fire.

What happens if you put a 25A machine on a 200 watt refrigerator?

The machine will not protect the wiring from overheating if there is a short circuit or prolonged overload. For example, when the compressor is closed, the current can reach 100A, and the 25A machine will work only after a few seconds - during this time the wires will have time to melt. In addition, such an automatic machine will not save from current leaks, unless an RCD is installed.

6. Features of connection in the garage: humidity, dust, voltage drops

A garage is not a house. Here are other conditions:

• 🌧️ High humidity (condensate, puddles from the car).
• 🔥 Temperature swings (In winter - minus, in summer - plus 30 ° C).
• ⚡ Unstable tension (especially if you have a garage with a common transformer substation)

Therefore, for the garage refrigerator you need:

1. Selecting the machine and the RCD in dust-proof (IP44 or higher).
2. install a socket with cover and grounding.
3. Use it. voltage stabilizerif there are frequent jumps on the network (for example, Resanta ASN-500).

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Attention: If there's no grounding in the garage, connecting the refrigerator through a regular outlet without a RCD is strictly prohibited - if the insulation breaks down, the body will be under tension, and touching it will be deadly.

7. How to check if the machine is working properly

After installing the machine and the RCD, you need to make sure that the system protects the refrigerator properly. Do three tests:

1. Automatic test:

   Connect to the refrigerator outlet load-tester (or a 2 kW high-powered hair dryer). The machine should be turned off within 1-2 seconds. If not, it is defective or misfitted.

2. The RCD test:

   Press the “Test” button on the RCD – it should be instantly disconnected. If not, the RCD is malfunctioning.

3. Leak test:

   With a megaohmmeter, check the resistance of the refrigerator insulation (should be at least 1 MH). If below, there is a risk of breakdown.

If at least one test is not passed, Don't turn on the refrigerator. until the problem is fixed!

💡

The machine and RCD are not a luxury, but a mandatory security measure. The refrigerator is 24/7 and even a small wiring fault can cause a fire, especially in a garage with combustible materials.

FAQ: Frequent questions about refrigerators

Can I connect the refrigerator without a machine directly to the shield?

Nope. Without a machine, the refrigerator remains without protection from short circuits and overloads. Even if the wiring is new, the risk of fire when closing in the compressor remains.

What machine to put in the refrigerator ATLANT MXM 1705 150 watts?

This model will fit the machine Type C 10A and RCD 30 m.. If the wiring is old (aluminum), it is better to take the machine on the 6A. and a separate line.

Do I need a ground for the refrigerator in the garage?

Yes, I will. Without grounding, the RCD may not work when current leaks to the body. If there is no grounding, use it. splitter Or refuse to install the refrigerator.

Can I use a difaute instead of a machine + RCD?

Yes, a difautomat (e.g., ABB DS201 16A 30mA) replace both devices. But when it is triggered, it is more difficult to determine the cause (overload or leakage). For the garage, it's better to split the protections.

What to do if the machine knocks out when the refrigerator is turned on?

The reasons may be:

• Weak automatic (replace with a larger denomination, taking into account the starting currents).
• Short circuit in the refrigerator (repair required).
• Failure of the RCD (check the button "Test").
• Poor contact in the socket or fork (call the multimeter).