Extra low frequency electric and magnetic fields during live-line maintenance

Nowadays different live-line maintenance methods are widely applied because of their economic and technical benefits. The different valid regulations are not always strict enough to guarantee the proper safety of the workers. In these regulations the criteria of the investigation is the shielding of the electric field. The proper way to shield electric field is wellknown: all the conductive clothing applied on high voltage live-line maintenance follow the principle of a Faraday cage. Although this principle seems theoretically easy, in practice many of conductive clothing cannot guarantee the proper electric shielding during the work. It is necessary to compare different conductive clothing to determine which construction is the most effective to protect the worker against electric field [1-4]. Another important thing is the proper shielding of extra low frequency magnetic field. Besides the electric field, this field is present during different live-line works as well. The long-term health effects of this magnetic field are still unexplained and there is not any effective practical way yet to shield it. Laboratory measurements and simulations are needed to investigate the magnetic field inside the different types of conductive clothing as a function of current flowing through the conductors near the live-line workers. The topic is practical and up-to-date: it is essential to minimize the risk on the workers during any type of work, especially during live-line maintenance. It is not acceptable to use any live-line methods without any effective shielding, if the loading current generates higher magnetic field than the limits of the valid regulations.