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Both Standards EN 50522 and IEEE 81 propose the fall of potential method (FPM) to carry out the measurement of the resistance to earth ($R_{\text{ES}}$) of an earthing system (ES). However, in urban areas, the recommended distances between the ES and auxiliary electrodes are not easy to respect, due to the presence of buildings and tarmac. Furthermore, unknown buried metallic parts and interconnections among ESs could modify the earth potential profile of the area, affecting the measurement results. In this paper, the key-issues that influence the measured $R_{\text{ES}}$ when the FPM is used in an urban environment are presented. A parametric analysis, carried out with Comsol Multiphysics, quantifies the errors due to wrong positioning of the auxiliary electrodes and due to the presence of interconnected ESs in the proximity of the ES under test. In addition, a real case of field measurement is described, emphasizing the main aspects that could compromise the results. Finally, practical suggestions to reduce errors are provided. [ABSTRACT FROM AUTHOR]

In urban and industrial areas, a relevant presence of buried metallic objects (e.g., gas and water pipes, etc.) can be detected. Usually, these elements are imagined as widespread meshed metallic grids in a good contact with the soil. In the last years, an arising interest on their role in the identification of a global earthing system has been expressed by the scientific community. Unfortunately, the geometrical and electrical properties of this kind of buried metallic parts cannot be provided by any documentations. This is mostly due to the fact that no trustworthy schemes are provided, as the management of these metallic parts is responsibility of different companies, which have installed them during several years. In order to characterize the buried metallic elements with reference to the electrical safety issue, the main quantity of interest is their resistance to earth. With this aim, a field measurement campaign was organized and the resistance to earth of more than 800 metallic objects has been evaluated through a simplified measurement protocol. In this paper, the measurement protocol, the setup, the results, and their analysis are reported. [ABSTRACT FROM PUBLISHER]

The acceptability of pulsed electric field (PEF) processing as an alternative method for liquid food preservation requires the elimination, or at least the reduction, of all the effects accompanying the flow of electric current. Metallic particles might be released from the electrode material as a result of electrically driven electrochemical reactions. The presence of such metallic particles can affect the quality and the safety of PEF-processed food. This paper investigates the effect of varying the parameters of applied electric pulses on the amount of released metals, aiming to reach the optimum conditions. It is expected that reducing the rate of releasing metals from the electrodes will extend their lifetime and reduce the running cost of the PEF process. [ABSTRACT FROM PUBLISHER]