Metallurgical Evidence of Arc Tracking as an Ignition Source

Arc tracking (arcing across a carbonized path) is a common cause of electrical fires in polymer insulated components, yet very few publications are dedicated to the study of this phenomenon due to its unstable behavior and variability. Conversely, metallurgical investigations associated with electrical arcing through air or arcing through charred insulation during fire exposure are well represented in published literature.

This presentation will describe a unique laboratory investigation designed and performed by an interdisciplinary team at Engineering Systems, Inc. (ESi). The purpose of the investigation was twofold: (1) to design an experimental setup that repeatedly produces ignition from arc tracking using conditions typical of a household electrical system and environment, and (2) to metallurgically characterize the evidence associated with arc tracking. This presentation will review both the experiment methodology and results, which emphasize the importance of laboratory testing for identifying arc tracking in polymer insulated components as a failure mode.