FE Investigation and Analysis of Poor Electrical Connections and Related Fire Investigation Case Studies
DOI:
https://doi.org/10.51501/jotnafe.v39i1.165Keywords:
Poor connections, Fire Investigation, Overheating Electrical Connections, glowing connections, electrical overheating, electrical ignition sources, liquid oxides, liquid oxide conductor, high-resistance connections, high-temperature oxidation, forensic engineeringAbstract
Overheating poor electrical connections (OPCs) are a ubiquitous ignition source of structure fires. Yet, knowledge of the intimate process between conductors at the connection point is relatively undocumented on the microscopic scale. For an OPC, it is ordinary for a filament or pool of liquid oxide to be the main current-carrying conductor at the point of overheating. This paper examines the overheating phenomena from a materials science perspective using photography through the stereo microscope, cross-sectioning, electron microscopy, and specialized techniques under the metallurgical microscope. Two case studies are presented in the second half of this paper. The first presents an artifact from field testing performed by a commercial cooking appliance manufacturer and introduces a real-world example of an OPC that did not ignite surrounding materials. The second is from a fire investigation of a food processing plant where prior research on OPCs informed expert opinions at trial and influenced the results.
References
V. Babrauskus, Electrical Fires and Explosions, New York: Fire Science Publishers, 2021.
C. Korinek, T. Korinek and H. Lopez, “Pre- and Post-Flashover Characteristics of an Electrically Overheated Poor Connection Between Copper and Steel,” in Fire and Materials, San Francisco, 2013.
C. Korinek and T. Korinek, “Poor Electrical Connections: Physical Features, Materials Characterization, and Newly Identified Characteristic Traits, Before and After a Fire,” in Fire Science and Technology (ISFI), Chicago, 2018.
J. Shea, “Glowing Contact Physics,” in IEEE Holm Conference on Electrical Contacts, Montreal, 2006.
Principles of Electronic Materials and Devices, New York: McGraw-Hill, 2006.
G. Garnaud, “The Formation of a Double Oxide Layer on Pure Copper,” Oxidation of Metals, vol. 11, no. 3, 1977.
J. Shea and X. Zhou, “Material Effect on Glowing Contact Properties,” in IEEE Holm Conference, 2007.
S. Bradford, Chapter on Fundamental of Corrosion in Gasses, Handbook Volume 13 - Corrosion, Materials Park, Ohio: ASM International, 1987.
Properties and Selection: Nonferrous Alloys, Materials Park, Ohio: ASM International, 1990.
M. Benfer and D. Gottuk, “Electrical Receptacles - Overheating, Arcing, and Melting,” in FIRE SAFETY SCIENCE, 2014.
Introduction to Practical Ore Microscopy, 1989.
D. Shishin and S. Decterov, “Critical Assessment and Thermodynamic Modeling of the Cu–O and Cu–O–S Systems,” CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry, vol. 38, pp. 59-70, 2012.
Y. A. Chang and K.-C. Hsieh, Phase Diagrams of Ternary Copper-Oxygen-Metal Systems, Materials Park, Ohio: ASM International, 1989.
E. Ehlers, The Interpretation of Geological Phase Diagrams, San Francisco: W. H. Freeman and Co., 1972.
M. Noguchi and H. Yakuwa, Lecture on the Fundamental Aspects of High Temperature Corrosion and Corrosion Protection Part 1: Basic Theory, 2016.
W. J. Meese and R. Beausolie, “Exploratory Study of Glowing Electrical Connections,” NIST, Washington, D.C., 1977.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2022 Journal of the National Academy of Forensic Engineers
This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.
All rights © Journal of the National Academy of Forensic Engineers.
Full statement regarding the author's license of copyright to the NAFE is shown on the Copyright section of the Submissions Page.
