There are various safety criteria to consider when installing a wallbox for your electric car. On this page, we have summarised all the important points that you need to consider when installing your wallbox. Here you will not only find out which components you need in addition to your wallbox, but also important details about the electrical connection, the necessary fuse protection and obtaining any necessary authorisations. With these tips, you will always be on the safe side.
Worth knowing
No other loads such as garage sockets, lighting, washing machine etc. may be connected to the power line leading from the fuse box to the wallbox. The simultaneity factor of 1.0 therefore applies to the wallbox supply line.
The simultaneity factor takes into account that, as a rule, not all devices in a system or circuit are always operated simultaneously and at full power. However, this must be assumed for a wallbox. Therefore, the connected load of the wallbox must be maintained at 100%.
The cable type and cross-section must always be customised according to the required available power and the local conditions.
Several factors play a role here, such as the length of the cable, the ambient temperature and the so-called. "Laying method". Example: A cable laid in concrete dissipates the heat generated by the flow of electricity differently than a cable laid "in the air" and can therefore be loaded differently under certain circumstances. In order for the electric car to be charged with a charging power of 11-22 kW (three-phase), the supply cable must be 5-core. A 3-core cable is sufficient for single-phase charging (up to 3.7 kW). It is best to have the required cable type and cross-section determined and installed by a qualified electrician.
We generally recommend preparing the power line for a three-phase connection wherever possible and, if in doubt, choosing a larger cable cross-section to ensure future-proofing. Electric cars will probably have higher charging capacities and battery capacities in the future.
Residual current circuit-breakers have the task of protecting people in the event of a fault in electrical systems. There are two main types:
Type A: reacts to AC and pulse residual currents (alternating current)
Type B: "all-current sensitive"; also reacts to direct fault currents (alternating current and direct current)
A residual current circuit breaker of at least type A is mandatory for every wallbox or charging station. However, fault currents based on direct current can also occur in electric cars. Some electric cars have an internal safety device that recognises these residual currents and protects the user from them, but others do not. If you do not know whether your electric car has this protective device, or if other (unknown) vehicles could also charge at your charging station, an all-current-sensitive residual current circuit breaker must be installed.
Wallbox manufacturers are increasingly tending to install an RCD in their wallbox that is also suitable for detecting DC residual currents. This protects you from DC residual currents. A wallbox with an integrated all-current-sensitive RCD is somewhat more expensive, but you are on the safe side.
The RCD type A EV was specially developed for the requirements of electromobility and is our recommendation if no other DC residual current protection is available in the wallbox.
The approval process and the power value from which a registration or authorisation must be made with your responsible grid operator varies from grid operator to grid operator.
In the area of responsibility of Mittelhessen Netz GmbH, charging stations with a power of up to 12 kW must be registered and authorised with a power greater than 12 kW.
In all other grid areas, please contact the respective grid operator for more information.
Installation by specialised personnel only
To ensure professional installation and your safety, installation, assembly and maintenance work may only be carried out by a qualified electrician who is familiar with the standards and installation regulations and is fully responsible for the installation.