Wallbox installieren — Was du vorher wissen musst

Installing a wallbox — What you need to know beforehand

Do you own an electric car or are you planning to buy one? Then there's no way around having your own wallbox. However, simply buying one isn't enough. Before the wallbox is mounted on the wall, there are several things to clarify – from the house connection and the cable cross-section to the correct circuit protection.

This guide will tell you step by step what requirements are necessary, what you need to pay attention to, and which typical mistakes you should avoid.

Why a wallbox and not just a regular wall socket?

In principle, an electric car can also be charged using a standard household socket. The problem is that a household socket is not designed for a continuous load of 2.3 kW. This can lead to overheating of the wiring—especially in older installations.

A wallbox, on the other hand, delivers between 3.7 kW and 22 kW of charging power, depending on the model. This means significantly shorter charging times. Furthermore, the wallbox communicates with the vehicle and automatically adjusts the charging current. Therefore, charging is not only faster but also safer.

What charging power is appropriate?

Before you decide on a wallbox, you should choose the appropriate charging capacity:

  • 3.7 kW (single-phase, 16 A): Sufficient for plug-in hybrids and low-mileage drivers. However, a full charge takes a very long time depending on the battery size.
  • 11 kW (three-phase, 16 A): The standard for most households. This is enough to fully charge an average electric car overnight without any problems. Furthermore, this option only requires notification, not a permit.
  • 22 kW (three-phase, 32 A): For frequent drivers or commercial use. However, approval from the grid operator is required. Furthermore, the house connection must be appropriately sized.

For most applications, an 11 kW wallbox is therefore the right choice.

Requirements for the house connection

First, you need to check if your home electrical connection has sufficient power reserves. An 11 kW wallbox requires approximately 16 amps per phase continuously. Therefore, your existing electrical connection should be able to handle this additional load.

Here's how to proceed:

  1. Contact your network operator: Register your wallbox with your network operator. For 11 kW, registration is usually sufficient. For 22 kW, you need approval.
  2. Check the meter box: Is there enough space for additional protective devices? If not, a larger distribution board may be necessary.
  3. Determine cable length: The distance between the meter box and the wallbox location determines the required cable cross-section.

Conductor cross-section — The heart of the installation

The conductor cross-section is one of the most important factors. Conductors that are too thin lead to voltage drop and, in the worst case, to overheating.

For an 11 kW wallbox (guide value - check with an electrician!):

  • Up to 15 m: 5 x 2.5 mm²
  • 15–25 m: 5 x 4 mm²
  • Over 25 m: 5 x 6 mm²

For a 22 kW wallbox (Guideline value - check with an electrician!):

  • Up to 15 m: 5 x 4 mm²
  • 15–25 m: 5 x 6 mm²
  • Over 25 m: 5 x 10 mm²

These values ​​are guidelines. The exact calculation also depends on the installation method and the ambient temperature. Therefore, this should always be calculated by a specialist company.

👉 You can find suitable cables in our shop

Protection — residual current circuit breaker and miniature circuit breaker

Proper protection is crucial for safety. Normally, you'll need two protective devices for this:

Residual current circuit breaker (RCCB)

The residual current device (RCD) protects people from electric shock. At least a Type A RCD is mandatory for wallboxes. However, many manufacturers recommend a Type A-EV or even a Type B RCD, as wallboxes can generate smooth DC fault currents during charging.

Some wallboxes—for example, theFronius Wattpilot series —already have integrated DC residual current monitoring (6 mA). In that case, an external Type A residual current device (RCD) is sufficient. However, you should always check this in the installation instructions.

👉 Residual current circuit breakers (RCCBs) in the shop:

Circuit breaker (MCB)

The circuit breaker protects the wiring from overload and short circuits. For an 11 kW wallbox, you need a 3-pole circuit breaker with a 16 A rating and C-curve characteristic. The C-curve is important because wallboxes can have higher inrush currents briefly when switched on.

Alternatively, you can use a combined residual current circuit breaker (RCCB) and miniature circuit breaker (MCB). This saves space in the distribution board.

👉 Circuit breakers in the shop:


👉 FI-LS combination:

Surge protection — often forgotten, yet important

One point that is often overlooked is surge protection. Especially with wallboxes that have integrated electronics and Wi-Fi, a nearby lightning strike or a switching surge can cause damage.

A Type 2 surge arrester in the distribution box protects the entire installation. This is a worthwhile investment, especially if you are installing the wallbox in a detached garage or carport.

👉 You can find surge protectors in our shop here

Choosing the right wallbox

Several factors play a role in the selection:

  • Charging power: 11 kW or 22 kW — depending on requirements and house connection.
  • Integrated DC residual current monitoring: Saves on the more expensive Type B RCD.
  • Connectivity: WLAN, LAN, Bluetooth — important for PV surplus charging and load management.
  • Authorization: RFID cards or app control, relevant for multi-family dwellings.
  • Cable length: Models with permanently attached cable (5 m / 7.5 m) or with socket (Type 2).

Established manufacturers includeFronius with the Wattpilot and KEBA with the KeContact series . Both offer solid workmanship, good app integration, and PV surplus charging.

Who is allowed to install the wallbox?

Short answer: A licensed electrical contractor. The installation is not a DIY project. Connecting to the distribution board, laying the supply cable, and configuring the protective devices require expert knowledge.

Additionally, the installation must be carried out and documented according to applicable standards (ÖVE/ÖNORM in Austria, VDE in Germany). Without proper installation, insurance coverage may be voided in the event of damage.

Checklist: Installing a wallbox

Finally, the most important points:

☐ Check house connection capacity
☐ Inform network operator / Obtain approval
☐ Choose a wallbox model (performance, features, DC protection)
☐ Determine location, measure cable length
☐ Calculate conductor cross-section
☐ Select residual current circuit breaker (Type A, A-EV or B)
☐ Plan for a circuit breaker with characteristic C
☐ Consider surge protection
☐ Check space in the distribution box
☐ Hire a qualified electrician
☐ Have the installation checked and documented

Conclusion

Installing a wallbox isn't rocket science—provided you plan correctly. The combination of a suitable cable cross-section, proper circuit protection, and a qualified electrician ensures that you can charge your electric car safely and efficiently.

If you have any questions about selecting the right protective devices or cables, just write to us. We'll be happy to help.

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