Nature of Series-Arc Faults and Parameters Affecting the Risk of Domestic Electrical Fires

The main cause of electrical fires, which is more severe in nature than non-electrical fires, is the series-arc fault. In this paper, the properties of series-arc faults are studied and the parameters affecting the risk of domestic electrical fires are analysed. In particular, a series-arc fault generator, made to align with the international standards, is used to study the characteristics of seriesarc faults in a domestic electrical installation. The waveforms of common domestic equipment, in the absence of a fault and in the presence of a fault, are examined in detail. It is seen that arc current waveform can be identified as having a vertical edge appearing after the zero-crossing point. Further, the impact of series-arc faults on igniting a fire in domestic electrical installations are analysed using thermal imaging. Finally, ability of the most commonly used insulation materials which may aid the initiation of electrical fires due to the series-arc faults has thermally categorized. The study has shown that even a 2A arc current that is sustained for 2s can auto-ignite PVC, the most common insulation material in domestic installations.