How to connect the air conditioner to the power supply

How to connect the air conditioner to the power supply

Connecting the air conditioner to the power grid is one of the most important intermediate stages of installing a split system. At the same time, it can not be called difficult, especially if you have the skills to work with wiring. However, there are some pitfalls in this case that should be taken into account.

In this article, we will tell you in detail how to connect the air conditioner to the network, which cable and which outlets are better to use. We will try to answer the most important questions so that you can easily understand how to connect split systems yourself. However, we still do not recommend doing this work yourself if you do not have sufficient experience and/or knowledge.

General information

connecting the air conditioner to the network

Before we get to the main question — how to connect an air conditioner to the power grid-let’s figure out the basics. Without them, it is impossible to correctly design an electrical connection.

First of all, you should understand that most air conditioners on the market are quite powerful devices. We recommend connecting the air conditioner directly to the meter, and not to the line in the apartment. This way you will protect the rest of the wiring, avoiding overcurrent.

However, there are exceptions to any rule. You can easily connect the split system to the apartment power grid, if the following conditions are met:

  • A 20 amp automatic machine is installed on the connection line of the split system;

  • Low-power air conditioner (up to 1.5 kW);

  • There are no other powerful devices on the connection line that consume a lot of electricity;

  • The wiring in the apartment consists of cables with a cross-section of at least 2.5, and preferably 4 mm2.

If these conditions are met, you can try to connect the device to the general apartment power grid. If one or more conditions cannot be met, you can connect the split system temporarily, but at the same time as soon as possible to equip a suitable power grid to power the air conditioning system in the apartment.

Main line

We have already written above, under what conditions it is possible to connect a split system directly to your home power grid. However, we recommend that you allocate a separate main line that will connect to the counter. This way you will protect the apartment power grid from overloads.

The main line connects the indoor unit to the electrical panel in the apartment. The cable for laying the main line is selected based on the power of the air conditioner. We will tell you more about this later in this article. The operating current of the automation is also calculated based on the characteristics of the device. To do this, use the formula:

Air conditioner power W/supply voltage + 30%

The main line is placed in a pre-prepared wall chase. After installation it’s plastered and a finishing finish is carried out on top.

Also, the wires can be mounted directly on the wall, without wall chasing. But in this case, communications need to be closed with a decorative plastic box. This is not the most popular option, since such solutions do not fit well into expensive designer repairs. But, if the finishing is already completed, there is simply no other way to lay the wires.

Automation and RCD are traditionally placed in the electrical panel. It must be grounded!

Auxiliary line

If you install the air conditioner yourself, you will face the need to lay an auxiliary electrical line. They connect the indoor and outdoor unit together. At the same time, the internal unit is the leading one, through it the split system is controlled.

The auxiliary line is also located in the strobe, but together with the copper tubes. Freon will circulate through them. Such a bundle of wires and tubes is called a «route». After installation, the track is plastered and a finishing finish is carried out on top.

air conditioner route

If the air conditioner is installed after finishing repairs, you will have to hide the communications in a decorative box. In short, everything is the same as in the case of the main line.

For the auxiliary line, a wire with a cross-section of at least 2.5 mm2 is selected. In this case, the cable must be multi-core. But when selecting, you should also pay attention to the power of the air conditioner. We recommend taking wires with a small margin in cross-section.

Selection of components


connection cable кондиционера

The first question that you should ask yourself before installing the line is which wire to use? Pay attention to the following parameters:

  • Network type

In modern new buildings, there is grounding by default. Therefore, a three-core wire is usually used for laying the main and auxiliary lines. And, besides, most often it is necessary to connect a three-phase air conditioner;

  • Power of the air conditioner

The reference literature on electrical engineering has all the necessary information about the selection of the cable cross-section depending on the power of the device. On average, for devices with a power of up to 3 kW, wires of 2 mm2 are used, up to 5 kW — 2.5 mm2, from 7 kW — 4 mm2. These are just general instructions, be sure to refer to the reference literature when selecting a section;

  • Operating conditions

The cable must withstand the conditions for which it was purchased. We recommend using wires of the VVG type. They have various modifications, including non-flammable and flat. VVG cables are durable and cost acceptable.


socket for connection кондиционера

The outlet into which the plug of the air conditioner will be connected must meet a number of requirements:

  • Grounding IS MANDATORY. Or you can use a relay;

  • It must be connected to the power grid ONLY with copper wires. Aluminum wires are not suitable. If the socket is connected using aluminum wires, they need to be replaced with copper ones;

  • The connection to the shield must be carried out through an automatic machine.

Most modern sockets (so-called «Euro sockets») meet the necessary requirements. The main thing is to connect them correctly. You should understand that by law, the air conditioner must be connected by a specialist with a permit. Otherwise, the warranty will not apply to the outlet. Therefore, if you are not sure of your abilities, it is better to entrust the installation to a specialist.

Details about the connection

The electrical connection diagram of the air conditioner is indicated on the sticker, which can be easily found on the housing of the indoor unit. Below is an example of such a scheme.

air conditioner connection diagram

Start by looking for the electrical part in the air conditioner. It is usually located under the decorative cover on the right (see the figure below). In the electrical part, you will find places for wires. They are numbered and marked with different colors. This will help you not to get confused when laying an auxiliary line when you connect the outdoor unit to the indoor one.

After connecting the wires to the indoor unit, the bundle of cables goes to the outdoor unit. When connecting, you need to pay attention to the numbering and color designation.

In detail

Outdoor unit terminals

The principle of connecting the main line:

  1. Remove the decorative panel from the indoor unit and the small cover covering the electronic part of the air conditioner;

  2. Remove the cable holder at the bottom;

  3. Check the insulation of each core to avoid a short circuit;

  4. Remove a few centimeters of insulation at the end of each core;

  5. Insert the end of each wire into the terminals according to the diagram;

  6. Tighten the connection, but do not apply excessive force;

  7. At the output, fix the wire firmly in the clamp;

  8. Replace the protective cover and the decorative panel.

The auxiliary (interblock) line connects by the same analogy. After connecting the main and auxiliary lines, you need to check the correct connections. To do this, compare your work with the electrical circuit. It is better to take a picture on your phone at the installation stage.

If you are convinced that the work was done correctly, make a trial first activation. Everything is fine? Excellent. But there is still a freon injection of the system and full-fledged testing ahead. However, these are topics for individual articles.

A few words about automation

We have briefly figured out how to connect the split system yourself. But what about the vending machines? Are they needed? Is it worth spending money and time on this automation?

Yes, yes, and yes again. Automation and RCD are designed to protect the power grid from overload. At the same time, it is recommended to install both devices in order to achieve maximum protection and predictability in the operation of household appliances. The presence of automation is the basis for the correct installation of the power grid. And the RCD will provide more strict control of the operation of the devices, while informing you exactly where the malfunction occurred. It is convenient, practical, and safe.

However, the bundle of automatic + RCD has one minus-the dimensions. In some situations, this disadvantage can be critical. In this case, you can put a differential type switch. It is more compact and modern, but many times more expensive and cannot be repaired. If such a switch breaks, it will have to be completely replaced.


The topic of installing an air conditioner is complex and multifaceted. Within the framework of one article, it is impossible to describe all the features, including those related to connecting the device to the power grid. But we tried to tell you about the most important nuances that you should pay attention to.

We hope that we were able to answer the question of how to connect the air conditioner to the network and how to perform this difficult task yourself. Be sure to install automation and RCD on the air conditioner to avoid excessive voltage and short circuit.

And finally: if you are not confident in your abilities, it is better to use the help of a specialist. Working with electricity is always associated with a risk to life and health. A professional electrician costs a lot of money, but he will save you from unnecessary worries.

Any other questions? Ask them in the comments below. If you have had the experience of connecting a split system, share your experience. Tell us about the difficulties that you had to face. Give some useful recommendations for beginners. Also read other articles on our website. We wish you good luck!

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