Residual current monitors offer high reliability and safety to home EV charger users

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

Delivering cost-effective leakage current detection, the new series reduces EMI, aids preventive maintenance, improves the reliability of AC EV chargers and provides users confidence in the safety of their charging system.

Based on the company's Fluxgate technology, supplying best-in-class performance, the new series is an RCM type B.

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

As EVs become more popular, users need a reliable and safe way to charge their vehicles from their home AC supply. Because EVs employ a high-voltage battery, they are also a high-power energy source. This must 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 necessities demands a highly accurate method of monitoring AC and DC current leakages, with the capacity to measure leakages as low as 5mA, some 10,000 times smaller than the current flowing in the conductor.

The family accomplishes this using the company'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 series external test winding is also readily accessible to the customer to test the sensor.

The high reliability and safety of the family ensure that manufacturers and users of AC wall boxes and charging cables can take full advantage of the benefits provided by current leakage sensors. Among these is a reduction in EMI that can affect nearby electronic equipment, improving the overall electromagnetic compatibility of the charger.

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

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

It also gives EV owners more confidence, with current leakage sensors in an EV charger demonstrating the manufacturer's commitment to safety and quality. The company has backed this up with the high reliability of the series, which is supplied with a five-year guarantee.