A.4.1 General:
The effectiveness of the indirect contact protection measures by automatically switching off the supply to A.2 is checked as follows:
Exception: Where the calculation of the fault loop impedance or the protective conductor resistance is available and if the arrangement of the installation allows the length and cross section of the cable to be checked, verification of the continuity of the protective conductor may replace the measurement.
The cross-section of L and PE must be checked, this should not be a problem.
The continuity of the protective conductor can be measured with the Profitest 204+.
We have the verification of the length in the determination of the limits, also the cross sections of L and PE. Since all parameters of the electrical resistance are specified, the length of the line is directly proportional to the electrical resistance. Therefore the result of the protective conductor measurement with the Profitest 204+ fulfills the exceptional conditions and an additional loop impedance measurement is not required.
This is especially important when loop impedance measurement is not possible because of non-sinusoidal voltages, such as those generated by power converters, or when loop impedance measurement is not possible for other important reasons. If e.g. the measurement during operation may be dangerous for the examiner, or the effort would be too great to get to the appropriate ladder.