DEVELOPMENT, ADVANCEMENT, AND CURRENT CHALLENGES IN THE EXAMINATION OF SHORT CIRCUITS IN CONDUCTORS FOR FIRE INVESTIGATION PURPOSES

Abstract

The article highlights the relevance of the problem of establishing a causal relationship between a fire and a short circuit in conductors, which is associated with fire statistics in premises with electrical wiring and equipment. It is noted that electrical conductors are among the few carriers of trace information that remain after the destructive effects of fire due to the relatively high melting temperature of metal. The evolutionary path of the development of forensic examinations of short circuits in conductors recovered from fire scenes is traced, from its inception to the present state of expert practice. The constructive influence of a critical approach and the generalization of expert practice on the development and modification of methodological support for the examination of short-circuit melting is demonstrated. The main principles and approaches to the examination of molten marks in conductors are elaborated in accordance with the latest approved methodologies. The issue of the disputed reliability of a number of provisions in existing methodologies regarding the establishment of a direct or reverse causal relationship between a fire and a short circuit in electrical conductors is considered. The incorrectness of directly linking the metal structure of molten marks to the fire is indicated. Emphasis is placed on the importance of taking into account the effect of annealing on the structure of molten marks under fire conditions in order to avoid errors in its evaluation and, consequently, the formation of incorrect overall conclusions. Based on examples from expert practice, certain inconsistencies in existing methodological postulates regarding the causal relationship between a number of structural features of molten marks and the progression of environmental parameter changes under real fire conditions are presented. Attention is focused on the need for a deeper approach to the theoretical foundation of this field of research, particularly in terms of the analysis and evaluation of metallographic studies, processes of directional solidification, grain growth and formation, etc. The necessity of a comprehensive approach to solving expert tasks related to determining the cause of fire is emphasized. Concern is expressed regarding the risks of a simplified approach, in which the assessment of structure at the stage of forming the final conclusion is reduced to a formal comparison of the grain geometry of the studied sample with these features in “reference” images, rather than being the result of a thorough and in-depth analysis that takes into account external factors identified during the fire scene examination, the laws of crystallization in the examined molten marks, and other relevant aspects. Practical recommendations are proposed for addressing issues arising during these expert examinations in order to ensure their completeness and reliability.