Tests of Series Arcing and Arc Fault Detection Devices in Low Voltage Systems

Abstract: Unwanted electrical arcs are a concern in fire and electrical equipment safety. Arcs in electrical systems can be categorized into two main groups, traditionally called: Series and parallel arc faults, or more recently called low current and high current arc faults. To mitigate the effects of arc faults, Arc Fault Detection Devices (AFDDs) can be used. The intention of the IEC 62606 standard is that AFDDs can identify and mitigate potentially harmful arcs before they are of concern. However, there are no real-life datasets that prove this statement. In this study, tests are conducted to better understand the performance of the AFDDs and get an idea of how well they achieve their intended role. This study considers only the series arc fault phenomenon, under low voltage (230 V) conditions. A variety of AFDD brands are tested for their performance under resistive loads and a combination of resistive and capacitive loads. Arcing objects used in the experiments include parallel electrodes, a damaged plug and socket sample (damaged due to natural long-term overheating leading to contact arcing) and several brands of sockets. Arc faults were produced in sockets via a loose contact test. The experiments conducted were able to identify the differences between the AFDDs’ performances per brand, dependence of tripping on the electrical loads involved, and on the arcing type such as the brand of sockets involved. Instances of fire and arc object degrading occurred during the experimentation. The results showed that the AFDDs can provide some protection for the electrical system from series arc faults. However, not all series arc faults were mitigated before catastrophic results were observed. This is of concern as electrical fires are a significant cause of residential fires and the hints that AFDDs add the final part needed for total circuit protection may lead to complacency from the customer when it comes to electrical safety. This work also makes suggestions on how the standard requirement for AFDD testing could be modified to improve the performance of AFDDs.