How to prepare the electrical installation for an electric car charging station?

Preparation of Installation and Building Condition

Preparing your home electrical installation for charging an electric vehicle is a key step for safe, fast, and efficient charging. A well-designed infrastructure allows you to fully utilize the potential of electromobility and also prevents future complications. Ideally, it is best to prepare the electrical installation already at the project stage. Prepare a separate circuit with a sufficiently dimensioned cable to the garage or the future charging point. Request a reserve in the main distribution board and the possibility of easily increasing the main circuit breaker. This will make your work much easier, and such an installation is by far the simplest.

If you are planning installation in an older house, it is necessary to check the existing wiring. Aluminum conductors or insufficient cable cross-sections can be problematic, and it is often necessary to replace or reinforce part of the electrical installation. Even if your house already has newer copper wiring or has recently been renovated, it is still necessary to perform a check. If, in the past, an increase in current consumption or the addition of another circuit was not considered, it will also be necessary to reinforce or replace the installation. Therefore, if you are planning a renovation of the electrical installation, always opt for the possibility of a current reserve and also count on spare space in the distribution board, as it may come in handy in the future not only for installing a charging station.

If you are adding a circuit to the existing electrical installation, it is necessary to plan the route of the supply cable. Your distribution board will not always be located on the same wall where you want to have the charging station on the opposite side, and you will have to find a route for the new cable. In the case of garage charging, there is the option of a sub-distribution board directly in your garage, or you can expand the electrical installation there.

All interventions in the electrical installation should be left to a specialized person. Without the appropriate knowledge, we do not recommend making any changes or modifications.

Selection of the EV Charger

When choosing an EV charger, it is necessary to consider several parameters, which are based on your electrical installation and requirements. There are several types of chargers, from single-phase (230V) or three-phase (400V) with different power and types of protection. Also important are the charging parameters of your car and the type of charging connector.

Types of Connectors

On the European market, you will most often encounter the Mennekes Type 2. Type 1 is rarely seen, but CSS Combo 1 and 2 connectors are also popular. When choosing, also consider the length of the flexible cable for connecting to the car.

Charging Station Power

The maximum power of the charging station for electric vehicles is indicated in kilowatts (kW) and determines the charging speed. The higher the value, the faster the electric vehicle will charge. When choosing, focus not only on the charger's power but also on the car's limit. For example, a 22 kW charging station will be unnecessary for a car with a 15 kW limit. For home charging, options up to 22 kW are available.

You can calculate the approximate time to charge the battery from 0 to 80% using the following formula:

Charging time = Battery capacity (kWh) × 0.8 ÷ Charging power (kW) × 0.9

Type of Connectivity

You will commonly encounter chargers that allow communication via Bluetooth or Wi-Fi. There are also types without connectivity, in which case you lose the great advantage of monitoring. However, it depends on your preference which technology you choose.

Placement

There are two most common types of chargers – Wallbox (static) or free-standing (mobile). Again, it depends on your preferences.

Types of Protection

Every quality EV charger should have protections for current leakage, thermal fuse, etc.

More about the types, selection, and classification of chargers will be covered in another article. However, for proper installation, it is necessary to know some parameters in advance.

You can also find verified EV chargers on our e-shop.

Installation and Commissioning

Once you know the charging power of your electric vehicle and have selected the appropriate charger, you can start preparing the electrical circuit. It should be separate, intended only for the charging station. The protection of such a circuit depends on the power of the charger. For example, a 22 kW wallbox must be equipped with a 3×32 A circuit breaker, and the main circuit breaker of the house should have a reserve of up to 3×40 A. When choosing a single-phase charger, you must consider a power of only up to 3.7 kW; charging will be very slow, and generally, most chargers are three-phase. In addition, within the electrical installation, it is necessary to deal with the distribution of consumed currents on individual phases so that your circuit works well.

Wiring diagram in the distribution board up to the socket for connecting the charger

The installation must also be equipped with a type B residual current device (RCD), which protects against DC leakage currents that can occur when charging an electric vehicle. Some EV chargers already have a type B RCD built in, but many chargers do not have an RCD at all or only type A, which responds only to AC leakage, not DC.

Some manufacturers even offer RCDs exclusively designed for EV chargers. The types of active electrical components we have selected can be purchased here.

Cables must be dimensioned according to the planned power, route length, installation method, and possible voltage drop. For 16 A (1F–3F), the minimum cross-section is 2.5 mm², for 32 A (1F–3F), at least 6 mm². For future use, a five-wire cable for power up to 22 kW is recommended. Even if you do not currently use the maximum power, prepare the electrical installation for higher loads in the future. This way, you will avoid costly modifications. Due to the continuous load for several hours, we recommend always choosing a higher cross-section, for example, from 2.5 mm² to 4 mm², etc. This will eliminate greater cable heating and power losses during transmission.

The wallbox should be as close as possible to the parking space, ideally in the garage or under a shelter. If this is not possible, thanks to IP54 protection, it can also be installed outdoors. Make sure the wallbox is easily accessible and does not obstruct movement. The recommended installation height is 120 cm from the bottom edge to the floor.

The best way to connect the charger is to use wall sockets mounted directly on the wall.

Summary

When preparing the electrical installation for connecting an EV charger, it is crucial to think about future needs, safety, and compliance with applicable standards. A properly designed and implemented installation will ensure comfortable and safe charging of your electric vehicle for many years. Before installing a charging point in an existing house, it is necessary to have the electrical installation inspected, especially due to the high load on the wiring during charging. Always entrust the design and implementation to a qualified electrician who knows the current standards and requirements.

If you need help with selecting or installing a charger, do not hesitate to contact us, we will be happy to advise you.