A qualified electrician is a person who has - thanks to his or her specialist qualifications, theoretical and practical knowledge and experience, and knowledge of the regulations that must be observed for work on electrical equipment - is able to assess the work necessary and detect possible risks.

A qualified electrician must be able to detect possible risks and carry out work with which he or she is commissioned on his or her own account.

In contrast, a person who is trained in electrical work must be briefed, instructed, and trained if necessary in the work that he or she must carry out, the possible risks if the work is not carried out properly, and the necessary protection devices and measures.

This person is then able to carry out the work in question under the guidance and supervision of a qualified electrician.

Test intervals are to be taken from BGV A3 - Accident prevention regulations for electrical systems and equipment.

The corresponding test methods (inspecting, testing, and measuring) are described in the DIN VDE standards (e.g. DIN VDE 0701-0702).

The stipulations on in-series calibration in the DIN EN ISO 9000-9004 standard series include test equipment monitoring as an important element of quality assessment. Test equipment monitoring aims to ensure that all test equipment that is relevant to product quality produces correct measurements.

To ensure this, the test equipment must be regularly calibrated and traceable in accordance with national standards. In addition, the measured values must be documented.

Calibration is the determination and documentation of the deviation of the values displayed by a measurement device from the actual values or the deviation of the output variables of a piece of test equipment from the rated values.

Thus, calibration involves taking a measurement and comparing the values for the specimen with the values for an accurate and traceable reference in accordance with a documented procedure. The aim is to detect and document any deviations.

If the values displayed by a measurement device or the output variables of a piece of test equipment during calibration are outside permitted tolerances, there are two possibilities as to how to proceed:

1. The measurement device being tested is adjusted so that the values are again within the permitted tolerance range and is calibrated again.

2. No adjustment takes place because the user wishes to document the deviating measurements of the measurement device or test equipment over a long period of usage with defined objectives.

If your own quality assurance system does not specify other requirements, most manufacturers recommend an interval of between one and two years.

For measurement devices marketed by MERZ, we recommend an interval of no more than 24 months.

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