We can TEST it! - the New Type EV

Electrical Testing of Type EV RCCBs with PROFITEST MTECH and MXTRA Test Instruments

As a leading manufacturer of test instruments, GOSSEN METRAWATT provides professional electricians with suitable tools for testing and documenting the new type EV RCCBs in accordance with the standards using the PROFITEST MTECH and PROFITET MXTRA testers.

The new type EV RCCB was developed by Doepke GmbH especially for the purpose of charging electrical vehicles (EVs). It's destined for use in charging stations and so-called wall boxes, as well as electrical circuits in permanent installations which supply power to equipment of this sort. The task of the RCCB is to assure the necessary protection against residual shock current at the charging outlet. At the same time, it also safeguards any upstream RCD against the danger of not being tripped in the event of direct residual current, for example caused by defective charging equipment.

Why do we need type EV RCCBs?

Conventional RCCBs are not capable of maintaining their protective function when the DC component of the residual current reaches a given level, because this prevents zero point contact of the residual current signal characteristic. This applies in particular to smooth, direct residual current.
According to product standards for RCCBs, they're designed such that smooth, direct residual current with a value of 6 mA (types AC and A) or 10 mA (type F) is not permitted to prevent the protective device from functioning correctly. In contrast, larger values may cause saturation of the internal magnetic measuring circuit, which can lead to critically reduced sensitivity to all types of residual current, and may even entirely "blind" the respective RCCB.
With regard to protective measures, charge controllers for electric vehicles are available in different variants. However, in many cases this operating equipment is laid without any electrical isolation from the power supply network. As a result, these charge controllers are potentially capable of producing dangerous touch voltage with the possible consequence of residual shock current in the event of a fault. Thanks to the internal inverter electronics in the charge controller, no residual direct current can occur (source: Doepke).

Electrical Testing of Type EV RCCBs with the PROFITEST MTECH and PROFITEST MXTRA Test Instruments

Testing of RCCBs includes visual inspection, testing and measurement. Measuring method: By generating a fault current downstream from the RCD, is must be substantiated that the RCD is tripped no later than upon reaching its nominal fault current value and that the continuously permissible touch voltage value UL agreed upon for the respective system is not exceeded.

  1. Testing with Rising Residual Current (AC)
    According to DIN VDE 0100, part 600, rising residual current must be used for measurements in the evaluation of RCDs, and touch voltage at nominal residual current IrN must be calculated from the measured values. The Profitest generates a continuously rising residual current of (0.3 ... 1.3) x IrN within the system for the testing of RCDs. The instrument stores the touch voltage and tripping current values which were measured at the moment tripping of the RCCB occurred, and displays them.
    Measurement of contact voltage with 30% nominal residual current does not normally trip an RCCB. However, the tripping limit may be exceeded as a result of leakage current in the measuring circuit, e.g. due to interconnected consumers with EMC circuit such as frequency converters and PCs.
  2. Testing with Rising Residual Current (AC) for Type B RCDs
    In accordance with VDE 0413, part 6, it must be substantiated that, with smooth direct current, residual operating current is no more than twice the value of rated residual current IrN. A continuously rising direct current, beginning with 0.2 times rated residual current IrN, must be applied to this end. If current rise is linear, rising current may not exceed twice the value of IrN within a period of 5 seconds.
    Testing with smoothed direct current must be possible in both test current directions. 
    The type EV RCCB is tested with rising residual current up to 6 mA in accordance with defined stipulations.

  3. Measurement of Time to Trip with Alternating and Direct Current
  4. Storage of Measured Values with Subsequent Report Generation using ETC Software

Further product information can be accessed at:

Press Release No. 2014/06, January 2014 - Product Page PROFITEST MXTRA, MTECH

About Us

Gossen Metrawatt - Safety through Competence With more than 100 years of experience, we offer unique products in the field of measuring and test technology, as well as industrial metrology. Our products are distinguished by values such as quality, reliability, safety and advanced technology, as well as dynamic and ergonomic design, extremely easy operation and a unique innovative spirit. Consistent alignment to our customers’ requirements has firmed up our position as a worldwide market leader.

In addition to our measuring and test technology products for the electrical trade, industry and the field of medicine, we also offer customer-specific energy management solutions, power supplies and services.

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