Experiments were performed to study the effects of electric current and sample orientation on flame spread along the polyethylene (PE) insulation on copper wires. The flame spread rate vs. inclination angle showed a non-monotonic trend i.e., flame spread rate first decreased and then increased as the inclination angle increased. The molten polymer coating flew along the wire during the spread if the wire was inclined. For upward flame spread, a periodic flame spread phenomenon was observed due to the flowing of molten polymer. A sub-flame was observed to spread in the opposite direction to the primary flame. The flowing of molten insulation has little influence on upward flame spread rate. With the increase of the electric current, both the amount of molten insulation and the flame spread rate increased. The downward spread was shown to be more susceptible to the electric current in this study. For downward flame spread, the flowing molten polymer brought heat from the burning region to the preheat region and promoted the flame spread. A flame spread model concerning with both the orientation angle and electric current was developed in this study.

International Seminar on Fire and Explosion Hazards (9; 2019; Saint Petersburg, Russia). Proceedings of the Ninth International Seminar on Fire and Explosion Hazards [Электронный ресурс]: 21-26 April 2019, Saint Petersburg, Russia. Vol. 2 / Peter the Great St. Petersburg Polytechnic University, Autonomous Non-Profit Organization "Fire and Explosion Safety", Gefest Holding Ltd ; [edited by A. Snegirev [et al.]. — Электрон. текстовые дан. (1 файл : 98,7 Мб). — Saint Petersburg, 2019. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать, копирование). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/k19-97.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/k19-97>.