Accurate conductor cross-sections are of great importance when selecting protective equipment during the installation of grounding systems. For the tripping time of the overcurrent protection relays, it is absolutely necessary to carry out the control of cross sections suitable for the current. These studies are performed by loop impedance measurements.

The loop impedance is a source impedance measured between the protective earth and the line. If the phase conductor short-circuits the protective earth conductor, the predicted earth fault current that can potentially flow can also be detected. Earth resistance measurements can also be made by loop impedance method. For earth resistance loop test, three-wire connection is made as phase, neutral and ground. The resistances of the test leads are reset before the measurement.

The Regulation on Electrical Indoor Facilities, which came into force in 2004, covers the provisions for the establishment and operation of electrical indoor facilities. The principles of this regulation must be applied to newly installed facilities, if the existing facilities are completely replaced, if there is a clear danger of death, injury and fire in the existing facilities or if the existing facility presents a danger to other facilities in the vicinity.

The Regulation on Health and Safety Measures to be Taken in Workplace Buildings and Attachments, published in 2013, also specifies the minimum health and safety conditions required in workplace buildings and attachments.

Pursuant to these legal regulations, the project work of the electrical installation, installation, selection of materials and protective devices must be appropriate to the voltage and ambient conditions to be used. At the same time, maintenance, repair, control and operation principles should be made within the framework of these legal regulations.

In accordance with these legal regulations, employers have to have their electrical tests and controls regularly done and to keep control reports.

Our company, within the framework of electrical safety examinationsperforms cycle - loop impedance measurements in accordance with the relevant regulations, standards and test methods published by local and foreign organizations. The following standards are considered in these studies:

• TS HD 60364-4-43 Electrical installation in buildings - Part 4: Protection for safety - Part 43: Overcurrent protection
• TS HD 60364-4-44 ... Part 44: Protection against overvoltages Protection of the low-voltage installation against faults between high-voltage systems and earth