These days, the market is awash with companies offering electric vehicle chargers, with new ones popping up all the time. A quick Google search brings up 14 different charger suppliers, most of them with several models to choose from. In order to choose the right electric vehicle charger, the first thing is to ensure that it is CE marked, which means that the manufacturer guarantees that the product meets requirements stipulated by the authorities.
Zaptec Pro have been tested and certified by the accredited TÜV SÜD in Germany. This means that as an installer, you can be confident that the charger is in accordance with all the standards on which CE marking is based.
In addition to requirements applying to the product, there are also requirements applying to the installation work. One important safety requirement is that each connection point for AC charging must be individually protected by current-based earth fault protection with a trip threshold not exceeding 30 mA. You then have three choices:
- Type B
- Type A and equipment which cuts out at a DC current higher than that for which the protection can guarantee function
- Type F and equipment which cuts out at a DC current higher than that for which the protection can guarantee function
Earth fault protection is used to prevent people from getting an electric shock if there is a fault in an electrical installation. Earth faults can be caused by an insulation fault in the electrical installation or equipment connected to it. The bodywork of a car is connected to earth when it the car is charging, and if there is an earth fault, the earth fault protection will automatically disconnect the car from the power source. Without earth fault protection, the bodywork would become live, and touching the car could result in a dangerous electric shock.
Each charging station may have internally or externally installed protection. Note that if there is no internal protection in the charging station, external earth fault protection must be fitted to each charging station, which quickly becomes impractical and expensive in an installation with multiple chargers.
ZAPCHARGER PRO and Zaptec HOME both have inbuilt protection, which means that you do not need earth fault protection in your fuse box – only an automatic circuit breaker and double-insulated cable between the fuse box and charger. This makes the work of installation more cost-effective, both in terms of time and equipment.
The earth fault protection in ZAPCHARGER PRO and Zaptec HOME is Type B protection, which is the best system to prevent charging from cutting out at harmless DC currents.
Type B protection is smarter and more immune than a charging station with Type A protection and DC current detection. A charging station with Type A protection will stop charging if a DC current of 6 mA is detected, even though such a low current is entirely harmless. This is because Type A protection is not guaranteed to function at DC currents exceeding 6 mA. However, Type B protection will accept these harmless DC currents and thereby permit charging in a wider range of situations, while not compromising on safety in any way.
Earth fault protection must be tested regularly in accordance with the manufacturer’s instructions for use. This frequency varies, but most recommend testing at least twice a year. It is important to perform this testing in your fuse box. If you have a Zaptec charger, you do not have to do this for the charging station, because it automatically tests the earth fault protection before every single charge! This means that you can be confident that safety is guaranteed at all times, allowing you to spend your time on other things.
Written by Espen Håland and Svein Tore Karlsen