Some electric vehicle (EV) owners neglect important safety precautions when setting up their wall chargers and often face the consequences — don’t let that happen to you. Most countries require you to install a residual current device (RCD) and miniature circuit breaker for safe charging. Electric vehicle (EV) chargers need reliable protection against electrical faults. But what exactly are these “additional” devices and how do they ensure safety?
It may seem a little technical at first, but it’s actually easier to understand than you might think. By the time you’re done reading, you’ll know exactly why and how to protect your wall charger with a circuit breaker and RCD.
Do electric vehicle chargers need circuit breakers?
Yes, electric vehicle chargers require circuit breakers to prevent damage from electrical faults, sudden changes in grid voltage, and other unexpected events. Built-in protection features or additional devices in the building's electrical system provide protection for the wall box, the vehicle, and the entire power grid.
Do electric vehicle chargers need RCD protection?
Yes, electric vehicle chargers require RCD protection for safe operation. Some wall chargers include built-in protection features such as DC fault protection or an integrated RCD. Whether you need to install an external RCD is not up to the charger manufacturers, but to local regulations. If the installation of an external RCD is required, there are two options:
- Type A RCDs detect alternating and pulsating DC currents. This makes them suitable for wall chargers with built-in DC fault protection.
- A Type B RCD handles all types of faults, including DC currents, and is mandatory for chargers without DC fault protection.
If your charger has a built-in Type B RCD, you may not need an external one. However, always consult an electrician to ensure compliance with local regulations and safety.
Do ELNexus chargers need RCD protection?
Models, including our ELNexus charging stations , have built-in DC fault protection that switches off the charger in the event of a DC fault caused by the vehicle. The simple explanation is that the charger stops charging. However, a Type A RCD in the home distribution board is still required for full protection.
In addition to the RCD, you should install a miniature circuit breaker for overload and short circuit protection. If you are not sure what this device is, keep reading to find out.
Note : Wall chargers with integrated RCDs are often more expensive because of these added protection features. However, if you are required to install an external RCD, it may not be a wise investment.
What is a circuit breaker?
A circuit breaker is a safety mechanism in a building's electrical system. It is designed to protect the system when using electrical devices, such as wall chargers to charge your car. The breaker detects electrical faults and shuts off the power to prevent damage or even fire.
It works like a fuse, which is actually a different version of the same concept. When a fuse blows, you have to replace it. A circuit breaker “trips” and stops the electricity when there is a fault, and you can reset it to restore power.
Miniature circuit breakers, in particular, can handle currents up to 100 A and have a short-circuit capacity of up to 10 kA. Therefore, they are usually suitable for residential and commercial environments, while other types of circuit breakers are designed for high voltage.
What size circuit breaker do I need for an electric vehicle charger?
The size of the circuit breaker depends mainly on the maximum charging power of your wall charger. The circuit breaker should be dedicated only to the EV charger, which means that the power cable to the charging station should not be connected to other electrical consumers. Therefore, you only need to consider the requirements of the charger when choosing a circuit breaker.
What kind of circuit breaker is needed for an 11 kW charger?
For an 11 kW EV charger, a Type A circuit breaker with a rated current of 16 amps is required, as this is usually the optimal choice for these installations.
The circuit breaker ensures that the charging cable does not overheat. However, it will only be effective if a cable with the correct cross-section is used. If the cable is too thin, the protection may activate frequently or, worse, not protect the system in time.
Note : Regulations for using a circuit breaker with a charging station vary by country. Please consult an electrician for local installation standards.
What kind of circuit breaker is needed for a 22 kW charger?
The higher the charging power, the more protection is needed. We recommend using a 32 A circuit breaker for a 22 kW EV charger due to the higher power requirements.
This circuit breaker is designed to shut off quickly in the event of a problem and provides excellent protection, especially when many wall chargers are operating at the same time.
Note : In most countries, the requirement is to have one circuit breaker for each charger. This means you will need two circuit breakers for two chargers, three for three chargers, and so on.
Can I use a wall charger without a circuit breaker?
Yes, you can technically have a wall charger without a circuit breaker. However, if there is a problem with your home's electrical system, your insurance will likely refuse to cover the damage, as it will be considered your deliberate decision to ignore the safety requirement.
What cable is needed for a wall charging station?
Choosing the right power cable is crucial when setting up a wall charging station. First, it ensures safety, and second, it minimizes energy loss during charging.
For an 11 kW EV charger, a cable with a cross-section of **TYPE 2 is required.
