Revision of the way of classification of conductive clothing

In case of the bare-hand method which is often applied especially during high voltage live-line maintenance, conductive clothing is the most important protective equipment to shield the extra-low frequency electric fields - acting as a Faraday cage. During the classification process of these clothing the screening efficiency is inspected besides some other electrical parameters: this shows the effectiveness of a given clothing regarding to the shielding of electric fields. Practical complaints from the worker-side followed by calculations, simulations and measurements in the High Voltage Laboratory of Budapest University of Technology and Economics showed that electric fields inside the clothing may exceed the limits without any face protection; the main issue that these types of clothing may pass the screening efficiency test specified by the related standard. Based on our results a new arrangement has been introduced to improve the efficiency of the measurement while increasing its safety and reliability. This new method is proposed to be implemented in the new edition of IEC 60895. This paper introduces and compares the conventional and the suggested ways of measurements. All the results are proved by both calculations and measurements for validation.