Heat and Arcing Fire Causation at Conduit Connections

Abstract

Present methods of construction for most commercial and light industrial electrical systems utilize set screw type zinc alloy connectors with EMT conduit. The author has investigated the electrical and thermal properties of these conduit systems when current flow occurs through the conduit/connector junction. A fire hazard is shown to exist when the conduit/connector junction is loose. It is the authors opinion that many electrically precipitated fires are due to the phenomenon described in this paper but that these causes are not appropriately considered, in view of their likelihood, by fire investigators.