Boosting safety and reliability of home electric vehicle charging

LEM has launched a new product in its CDSR series of Residual Current Monitors. Now available with three output types – fault output, SPI bus, and analogue output – the new product brings an increased level of safety and reliability to AC wall boxes and charging cables. 

Offering leakage current detection, the new LEM CDSR reduces electromagnetic interference, aids preventive maintenance, improves the reliability of AC electric vehicle chargers and gives users confidence in the safety of their charging system.

Based on LEM’s Fluxgate technology, offering best in class performance, the new LEM CDSR is an RCM type B.

Compliant with international tripping standards (IEC 62752/62955/UL 2231), the CDSR family is suitable for 3.3 to 22kW AC charging systems and is offered in both single and three phase versions.

As electric vehicles become more popular, users need a reliable and safe way to charge their vehicles from their home AC supply. Because EVs use a high voltage battery, they are also a high-power energy source. This needs to be carefully monitored to avoid any electrical shock to users or damage to household switchboard protection such as the RCM A that protects the house from electrical hazards.

Meeting these requirements demands a highly accurate method of monitoring AC and DC current leakages, with the ability to measure leakages as low as 5mA, some 10,000 times smaller than the current flowing in the conductor.

The LEM CDSR family achieves this using LEM’s fluxgate technology with fixed jumpers phase current. This uses mechanical placement to optimise performance, making it the most accurate contactless technology available today.

It also ensures easy integration and layout of the power track design thanks to its unique vertical shape. Offering isolation in a compact solution, the CDSR’s external test winding is also readily accessible to the customer to test the sensor.

The high reliability and safety of the LEM CDSR family ensures manufacturers and users of AC wall boxes and charging cables can take full advantage of the benefits offered by current leakage sensors. Amongst these are a reduction in electromagnetic interference that can affect nearby electronic equipment, improving the overall electromagnetic compatibility of the charger. 

The CDSR can also aid in preventive maintenance, flagging up potential issues before they become severe and reducing long-term repair costs. The device allows the detection of minor leakages from the very first signs of a drift from normal behaviour.

By ensuring that current leakage issues are detected and resolved promptly, the CDSR family improves the overall reliability of AC EV chargers, reducing unplanned downtime.

It also gives more confidence to EV owners, with the presence of current leakage sensors in an EV charger demonstrating the manufacturer’s commitment to safety and quality. LEM has backed this up with the high reliability of the CDSR, which is offered with a five-year guarantee.