Imagine your home power network is like a three -lane highway. Each track is a phase on which electricity flows. Usually the traffic is evenly distributed over all three traces.
But if you now connect an electric car with a single -phase charger to a wall box, it is as if all cars suddenly want to travel on one track. This track is then overloaded, while the other two traces remain empty. This is called crooked load.
In Germany, this "highway" may be loaded with 20 amps. This corresponds to about 4.6 kW of power. So if your car pulls more electricity, the "track" will be overloaded.
Why is crooked load a problem?
- Overload: The overloaded track (phase) can overheat and, in the worst case, lead to damage to the electrical installation. Imagine that a lot of traffic leads to cracks in the asphalt!
- Imbalance: The power grid is designed for an even load of all three phases. A strong crooked load can lead to instability and disorders on the Internet. It would be as if the highway gets out of balance due to the uneven weight of the cars.
What does the Wallbox have to do with it?
The Wallbox is the "petrol station" for your electric car. It regulates the current flow and ensures that the crooked load does not become too large.
- Intelligent wall boxes: Modern wall boxes can measure the crooked load and adapt the charging current accordingly. This prevents a phase from being overloaded. They work like an intelligent traffic control center that distributes the cars evenly on the tracks.
- Adjustable wall boxes: With many wall boxes you can set the maximum charging capacity to limit the crooked load. This is as if you set a speed limit on the highway so that too many cars do not go on track at once.
In summary: Crooked load arises when the current is distributed unevenly to the three phases of the power grid. Wallboxes help to limit the crooked load and thus avoid damage to the electrical installation.