Metallurgical and composition analysis of melted marks due to electrical failures

Abstract

Electrical distribution wires with melted ends showing beaded, drop-shaped, and pointed shapes are frequently encountered after fires, which may be provide useful information on the cause and development of the fire. Various methods have been studied for identifying between primary melted marks (PMM), indicating arcing as the cause of the fire, and secondary melted marks (SMM), indicating arcing as a result of the fire. But in some major cases, PMM and SMM are difficultly identified just using one method. In this study, a correlation of such behavior with some macroscopic, the in-depth composition of carbon and oxygen quantitative analysis, the composition and the chemical state in the near-surface regions, and metallurgical analysis of PMM and SMM has been studied. As a result, the given fire cause is the integrative judgments of these methods.