Experimental Determination of Temperatures Achieved by Hot Particles Produced from Electrical Arcing

This work provides a novel testing methodology to determine the initial temperatures of ejected, arc-produced particles. Research from welding journals, theoretical papers and testing of light produced by arcing events have all reasonably concluded that the temperature of an electrical arc is in the range of 5,000 °C. Knowing the temperature of an electrical arc, as well as the initial temperature of any ejected particles produced from an arc, can greatly assist forensic engineers in establishing the temperature and energy of the particles striking a hard ground surface. This work uses both empirical testing and mathematical modeling to verify the initial temperature of these particles. The mathematical model is capable of assisting in the development of key probabilistic assessments regarding hot particle ignition in wildland fire investigations. The methodology in this work utilized a mathematical model to predict the vertical distance that ejected, arc-produced particles would fall and strike a hard surface while undergoing the isothermal, liquid-to-solid phase change. Empirically, particles will become permanently deformed when they strike the ground as they enter the liquid-to-solid phase change. By predicting where on its cooling curve a particle will be deformed by impact, a researcher can then determine the initiating temperature of the particle.